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diff --git a/Shower/Default/IS_QTildeShowerKinematics1to2.cc b/Shower/Default/IS_QTildeShowerKinematics1to2.cc
--- a/Shower/Default/IS_QTildeShowerKinematics1to2.cc
+++ b/Shower/Default/IS_QTildeShowerKinematics1to2.cc
@@ -1,192 +1,195 @@
// -*- C++ -*-
//
// IS_QTildeShowerKinematics1to2.cc is a part of Herwig++ - A multi-purpose Monte Carlo event generator
// Copyright (C) 2002-2011 The Herwig Collaboration
//
// Herwig++ is licenced under version 2 of the GPL, see COPYING for details.
// Please respect the MCnet academic guidelines, see GUIDELINES for details.
//
//
// This is the implementation of the non-inlined, non-templated member
// functions of the IS_QTildeShowerKinematics1to2 class.
//
#include "IS_QTildeShowerKinematics1to2.h"
#include "ThePEG/PDT/EnumParticles.h"
#include "ThePEG/Interface/ClassDocumentation.h"
#include "Herwig++/Shower/Base/ShowerParticle.h"
#include "ThePEG/Utilities/Debug.h"
#include "Herwig++/Shower/ShowerHandler.h"
#include "Herwig++/Shower/Base/Evolver.h"
#include "Herwig++/Shower/Base/PartnerFinder.h"
#include "Herwig++/Shower/Base/ShowerModel.h"
#include "Herwig++/Shower/Base/KinematicsReconstructor.h"
#include "Herwig++/Shower/Base/ShowerVertex.h"
#include <cassert>
using namespace Herwig;
void IS_QTildeShowerKinematics1to2::
updateChildren( const tShowerParticlePtr theParent,
const ShowerParticleVector & theChildren,
ShowerPartnerType::Type) const {
const ShowerParticle::Parameters & parent = theParent->showerParameters();
ShowerParticle::Parameters & child0 = theChildren[0]->showerParameters();
ShowerParticle::Parameters & child1 = theChildren[1]->showerParameters();
double cphi = cos(phi());
double sphi = sin(phi());
child1.alpha = (1.-z()) * parent.alpha;
child1.ptx = (1.-z()) * parent.ptx - cphi * pT();
child1.pty = (1.-z()) * parent.pty - sphi * pT();
child1.pt = sqrt( sqr(child1.ptx) + sqr(child1.pty) );
// space-like child
child0.alpha = parent.alpha - child1.alpha;
child0.beta = parent.beta - child1.beta;
child0.ptx = parent.ptx - child1.ptx;
child0.pty = parent.pty - child1.pty;
}
void IS_QTildeShowerKinematics1to2::
updateParent(const tShowerParticlePtr parent,
const ShowerParticleVector & children,
ShowerPartnerType::Type partnerType) const {
// calculate the scales
splittingFn()->evaluateInitialStateScales(partnerType,scale(),z(),parent,
children[0],children[1]);
// set proper colour connections
splittingFn()->colourConnection(parent,children[0],children[1],
partnerType,true);
// set proper parent/child relationships
parent->addChild(children[0]);
parent->addChild(children[1]);
parent->x(children[0]->x()/z());
// sort out the helicity stuff
// construct the spin info for parent and timelike child
// temporary assignment of shower parameters to calculate correlations
parent->showerParameters().alpha = parent->x();
children[1]->showerParameters().alpha = (1.-z()) * parent->x();
children[1]->showerParameters().ptx = - cos(phi()) * pT();
children[1]->showerParameters().pty = - sin(phi()) * pT();
children[1]->showerParameters().pt = pT();
setMomentum(parent,false);
setMomentum(children[1],true);
if(! ShowerHandler::currentHandler()->evolver()->correlations()) return;
SpinPtr pspin(children[0]->spinInfo());
if(!pspin || !ShowerHandler::currentHandler()->evolver()->spinCorrelations() ) return;
// compute the matrix element for spin correlations
IdList ids;
ids.push_back(parent->id());
ids.push_back(children[0]->id());
ids.push_back(children[1]->id());
Energy2 t = (1.-z())*sqr(scale())/z();
// create the vertex
SVertexPtr vertex(new_ptr(ShowerVertex()));
// set the matrix element
vertex->ME(splittingFn()->matrixElement(z(),t,ids,phi()));
// set the incoming particle for the vertex
// (in reality the first child as going backwards)
pspin->decayVertex(vertex);
// construct the spin infos
constructSpinInfo(parent,false);
constructSpinInfo(children[1],true);
// connect the spinInfo objects to the vertex
parent ->spinInfo()->productionVertex(vertex);
children[1]->spinInfo()->productionVertex(vertex);
}
void IS_QTildeShowerKinematics1to2::
reconstructParent(const tShowerParticlePtr theParent,
const ParticleVector & theChildren ) const {
PPtr c1 = theChildren[0];
ShowerParticlePtr c2 = dynamic_ptr_cast<ShowerParticlePtr>(theChildren[1]);
ShowerParticle::Parameters & c2param = c2->showerParameters();
// get shower variables from 1st child in order to keep notation
// parent->(c1, c2) clean even though the splitting was initiated
// from c1. The name updateParent is still referring to the
// timelike branching though.
// on-shell child
c2param.beta = 0.5*( sqr(c2->data().constituentMass()) + sqr(c2param.pt) )
/ ( c2param.alpha * p_dot_n() );
- c2->set5Momentum( sudakov2Momentum(c2param.alpha, c2param.beta,
- c2param.ptx , c2param.pty) );
+ Lorentz5Momentum pnew = sudakov2Momentum(c2param.alpha, c2param.beta,
+ c2param.ptx , c2param.pty);
+ pnew.setMass(c2->data().constituentMass());
+ pnew.rescaleEnergy();
+ c2->set5Momentum( pnew );
// spacelike child
Lorentz5Momentum pc1(theParent->momentum() - c2->momentum());
pc1.rescaleMass();
c1->set5Momentum(pc1);
}
void IS_QTildeShowerKinematics1to2::
updateLast( const tShowerParticlePtr theLast,Energy px,Energy py) const {
if(theLast->isFinalState()) return;
ShowerParticle::Parameters & last = theLast->showerParameters();
Energy2 pt2 = sqr(px) + sqr(py);
last.alpha = theLast->x();
last.beta = 0.5 * pt2 / last.alpha / p_dot_n();
last.ptx = ZERO;
last.pty = ZERO;
last.pt = ZERO;
// momentum
Lorentz5Momentum ntemp = Lorentz5Momentum(ZERO,-pVector().vect());
double beta = 0.5 * pt2 / last.alpha / (pVector() * ntemp);
Lorentz5Momentum plast =
Lorentz5Momentum( (pVector().z()>ZERO ? px : -px), py, ZERO, ZERO)
+ theLast->x() * pVector() + beta * ntemp;
plast.rescaleMass();
theLast->set5Momentum(plast);
}
void IS_QTildeShowerKinematics1to2::initialize(ShowerParticle & particle, PPtr parent) {
// For the time being we are considering only 1->2 branching
Lorentz5Momentum p, n, pthis, pcm;
assert(particle.perturbative()!=2);
Frame frame;
if(particle.perturbative()==1) {
// find the partner and its momentum
ShowerParticlePtr partner=particle.partner();
assert(partner);
if(partner->isFinalState()) {
Lorentz5Momentum pa = -particle.momentum()+partner->momentum();
Lorentz5Momentum pb = particle.momentum();
Energy scale=parent->momentum().t();
Lorentz5Momentum pbasis(ZERO,parent->momentum().vect().unit()*scale);
Axis axis(pa.vect().unit());
LorentzRotation rot;
double sinth(sqrt(sqr(axis.x())+sqr(axis.y())));
if(axis.perp2()>1e-20) {
rot.setRotate(-acos(axis.z()),Axis(-axis.y()/sinth,axis.x()/sinth,0.));
rot.rotateX(Constants::pi);
}
if(abs(1.-pa.e()/pa.vect().mag())>1e-6) rot.boostZ( pa.e()/pa.vect().mag());
pb *= rot;
if(pb.perp2()/GeV2>1e-20) {
Boost trans = -1./pb.e()*pb.vect();
trans.setZ(0.);
rot.boost(trans);
}
pbasis *=rot;
rot.invert();
n = rot*Lorentz5Momentum(ZERO,-pbasis.vect());
p = rot*Lorentz5Momentum(ZERO, pbasis.vect());
}
else {
pcm = parent->momentum();
p = Lorentz5Momentum(ZERO, pcm.vect());
n = Lorentz5Momentum(ZERO, -pcm.vect());
}
frame = BackToBack;
}
else {
p = dynamic_ptr_cast<ShowerParticlePtr>(particle.children()[0])
->showerKinematics()->getBasis()[0];
n = dynamic_ptr_cast<ShowerParticlePtr>(particle.children()[0])
->showerKinematics()->getBasis()[1];
frame = dynamic_ptr_cast<ShowerParticlePtr>(particle.children()[0])
->showerKinematics()->frame();
}
setBasis(p,n,frame);
}
diff --git a/Shower/Default/QTildeReconstructor.cc b/Shower/Default/QTildeReconstructor.cc
--- a/Shower/Default/QTildeReconstructor.cc
+++ b/Shower/Default/QTildeReconstructor.cc
@@ -1,2947 +1,2951 @@
// -*- C++ -*-
//
// QTildeReconstructor.cc is a part of Herwig++ - A multi-purpose Monte Carlo event generator
// Copyright (C) 2002-2011 The Herwig Collaboration
//
// Herwig++ is licenced under version 2 of the GPL, see COPYING for details.
// Please respect the MCnet academic guidelines, see GUIDELINES for details.
//
//
// This is the implementation of the non-inlined, non-templated member
// functions of the QTildeReconstructor class.
//
#include "QTildeReconstructor.h"
#include "ThePEG/PDT/EnumParticles.h"
#include "ThePEG/Repository/EventGenerator.h"
#include "ThePEG/EventRecord/Event.h"
#include "ThePEG/Interface/Parameter.h"
#include "ThePEG/Interface/Switch.h"
#include "ThePEG/Interface/ClassDocumentation.h"
#include "ThePEG/Interface/RefVector.h"
#include "Herwig++/Shower/Base/Evolver.h"
#include "Herwig++/Shower/Base/PartnerFinder.h"
#include "ThePEG/Persistency/PersistentOStream.h"
#include "ThePEG/Persistency/PersistentIStream.h"
#include "Herwig++/Shower/SplittingFunctions/SplittingFunction.h"
#include "ThePEG/Repository/UseRandom.h"
#include "ThePEG/EventRecord/ColourLine.h"
#include "ThePEG/Utilities/DescribeClass.h"
#include <cassert>
using namespace Herwig;
DescribeClass<QTildeReconstructor,KinematicsReconstructor>
describeQTildeReconstructor("Herwig::QTildeReconstructor", "HwShower.so");
namespace {
enum SystemType { UNDEFINED=-1, II, IF, F ,I };
struct ColourSingletSystem {
ColourSingletSystem() : type(UNDEFINED) {}
ColourSingletSystem(SystemType intype,ShowerProgenitorPtr inpart)
: type(intype),jets(1,inpart) {}
/**
* The type of system
*/
SystemType type;
/**
* The jets in the system
*/
vector<ShowerProgenitorPtr> jets;
};
struct ColourSingletShower {
ColourSingletShower() : type(UNDEFINED) {}
ColourSingletShower(SystemType intype,HardBranchingPtr inpart)
: type(intype),jets(1,inpart) {}
/**
* The type of system
*/
SystemType type;
/**
* The jets in the system
*/
vector<HardBranchingPtr> jets;
};
void combineFinalStateSystem(vector<ColourSingletSystem> & systems) {
// check that 1 particle final-state systems which can be combine
bool canCombine(true);
for(unsigned int ix=0;ix<systems.size();++ix) {
if(systems[ix].type!=F) continue;
if(systems[ix].jets.size()!=1) canCombine = false;
}
// return if can't combine
if(!canCombine) return;
// otherwise combine them
vector<ColourSingletSystem> oldsystems=systems;
systems.clear();
ColourSingletSystem finalState;
finalState.type = F;
for(unsigned int ix=0;ix<oldsystems.size();++ix) {
if(oldsystems[ix].type==F) {
for(unsigned int iy=0;iy<oldsystems[ix].jets.size();++iy)
finalState.jets.push_back(oldsystems[ix].jets[iy]);
}
else
systems.push_back(oldsystems[ix]);
}
systems.push_back(finalState);
}
void combineFinalStateShower(vector<ColourSingletShower> & systems) {
// check that 1 particle final-state systems which can be combine
bool canCombine(true);
for(unsigned int ix=0;ix<systems.size();++ix) {
if(systems[ix].type!=F) continue;
if(systems[ix].jets.size()!=1) canCombine = false;
}
// return if can't combine
if(!canCombine) return;
// otherwise combine them
vector<ColourSingletShower> oldsystems=systems;
systems.clear();
ColourSingletShower finalState;
finalState.type = F;
for(unsigned int ix=0;ix<oldsystems.size();++ix) {
if(oldsystems[ix].type==F) {
for(unsigned int iy=0;iy<oldsystems[ix].jets.size();++iy)
finalState.jets.push_back(oldsystems[ix].jets[iy]);
}
else
systems.push_back(oldsystems[ix]);
}
systems.push_back(finalState);
}
/**
* Return colour line progenitor pointer for ShowerProgenitor
*/
Ptr<ThePEG::ColourLine>::transient_pointer
CL(ShowerProgenitorPtr a, unsigned int index=0) {
return const_ptr_cast<ThePEG::tColinePtr>(a->progenitor()->colourInfo()->colourLines()[index]);
}
/**
* Return progenitor colour line size for ShowerProgenitor
*/
unsigned int CLSIZE(ShowerProgenitorPtr a) {
return a->progenitor()->colourInfo()->colourLines().size();
}
/**
* Return anti-colour line progenitor pointer for ShowerProgenitor
*/
Ptr<ThePEG::ColourLine>::transient_pointer
ACL(ShowerProgenitorPtr a, unsigned int index=0) {
return const_ptr_cast<ThePEG::tColinePtr>(a->progenitor()->colourInfo()->antiColourLines()[index]);
}
/**
* Return progenitor anti-colour line size for ShowerProgenitor
*/
unsigned int ACLSIZE(ShowerProgenitorPtr a) {
return a->progenitor()->colourInfo()->antiColourLines().size();
}
/**
* Return colour line size
*/
unsigned int CLSIZE(set<HardBranchingPtr>::const_iterator & a) {
return (*a)->branchingParticle()->colourInfo()->colourLines().size();
}
/**
* Return anti-colour line size
*/
unsigned int ACLSIZE(set<HardBranchingPtr>::const_iterator & a) {
return (*a)->branchingParticle()->colourInfo()->antiColourLines().size();
}
/**
* Struct to order the jets in off-shellness
*/
struct JetOrdering {
bool operator() (const JetKinStruct & j1, const JetKinStruct & j2) {
Energy diff1 = j1.q.m()-j1.p.m();
Energy diff2 = j2.q.m()-j2.p.m();
if(diff1!=diff2) {
return diff1>diff2;
}
else if( j1.q.e() != j2.q.e() )
return j1.q.e()>j2.q.e();
else
return j1.parent->uniqueId>j2.parent->uniqueId;
}
};
}
void QTildeReconstructor::persistentOutput(PersistentOStream & os) const {
os << _reconopt << _initialBoost << ounit(_minQ,GeV) << _noRescale
<< _noRescaleVector << _finalStateReconOption
<< _initialStateReconOption;
}
void QTildeReconstructor::persistentInput(PersistentIStream & is, int) {
is >> _reconopt >> _initialBoost >> iunit(_minQ,GeV) >> _noRescale
>> _noRescaleVector >> _finalStateReconOption
>> _initialStateReconOption;
}
void QTildeReconstructor::Init() {
static ClassDocumentation<QTildeReconstructor> documentation
( "This class is responsible for the kinematics reconstruction of the showering,",
" including the kinematics reshuffling necessary to compensate for the recoil"
"of the emissions." );
static Switch<QTildeReconstructor,unsigned int> interfaceReconstructionOption
("ReconstructionOption",
"Option for the kinematics reconstruction",
&QTildeReconstructor::_reconopt, 0, false, false);
static SwitchOption interfaceReconstructionOptionGeneral
(interfaceReconstructionOption,
"General",
"Use the general solution which ignores the colour structure for all processes",
0);
static SwitchOption interfaceReconstructionOptionColour
(interfaceReconstructionOption,
"Colour",
"Use the colour structure of the process to determine the reconstruction procedure.",
1);
static SwitchOption interfaceReconstructionOptionColour2
(interfaceReconstructionOption,
"Colour2",
"Make the most use possible of the colour structure of the process to determine the reconstruction procedure. "
"Start with FF, then IF then II colour connections",
2);
static SwitchOption interfaceReconstructionOptionColour3
(interfaceReconstructionOption,
"Colour3",
"Make the most use possible of the colour structure of the process to determine the reconstruction procedure. "
"Do the colour connections in order of the pT's emitted in the shower starting with the hardest."
" The colour partner is fully reconstructed at the same time.",
3);
static SwitchOption interfaceReconstructionOptionColour4
(interfaceReconstructionOption,
"Colour4",
"Make the most use possible of the colour structure of the process to determine the reconstruction procedure. "
"Do the colour connections in order of the pT's emitted in the shower starting with the hardest, while leaving"
" the colour partner on mass-shell",
4);
static Parameter<QTildeReconstructor,Energy> interfaceMinimumQ2
("MinimumQ2",
"The minimum Q2 for the reconstruction of initial-final systems",
&QTildeReconstructor::_minQ, GeV, 0.001*GeV, 1e-6*GeV, 10.0*GeV,
false, false, Interface::limited);
static RefVector<QTildeReconstructor,ParticleData> interfaceNoRescale
("NoRescale",
"Particles which shouldn't be rescaled to be on shell by the shower",
&QTildeReconstructor::_noRescaleVector, -1, false, false, true, false, false);
static Switch<QTildeReconstructor,unsigned int> interfaceInitialInitialBoostOption
("InitialInitialBoostOption",
"Option for how the boost from the system before ISR to that after ISR is applied.",
&QTildeReconstructor::_initialBoost, 0, false, false);
static SwitchOption interfaceInitialInitialBoostOptionOneBoost
(interfaceInitialInitialBoostOption,
"OneBoost",
"Apply one boost from old CMS to new CMS",
0);
static SwitchOption interfaceInitialInitialBoostOptionLongTransBoost
(interfaceInitialInitialBoostOption,
"LongTransBoost",
"First apply a longitudinal and then a transverse boost",
1);
static Switch<QTildeReconstructor,unsigned int> interfaceFinalStateReconOption
("FinalStateReconOption",
"Option for how to reconstruct the momenta of the final-state system",
&QTildeReconstructor::_finalStateReconOption, 0, false, false);
static SwitchOption interfaceFinalStateReconOptionDefault
(interfaceFinalStateReconOption,
"Default",
"All the momenta are rescaled in the rest frame",
0);
static SwitchOption interfaceFinalStateReconOptionMostOffShell
(interfaceFinalStateReconOption,
"MostOffShell",
"All particles put on the new-mass shell and then the most off-shell and"
" recoiling system are rescaled to ensure 4-momentum is conserved.",
1);
static SwitchOption interfaceFinalStateReconOptionRecursive
(interfaceFinalStateReconOption,
"Recursive",
"Recursively put on shell by putting the most off-shell particle which"
" hasn't been rescaled on-shell by rescaling the particles and the recoiling system. ",
2);
static SwitchOption interfaceFinalStateReconOptionRestMostOffShell
(interfaceFinalStateReconOption,
"RestMostOffShell",
"The most off-shell is put on shell by rescaling it and the recoiling system,"
" the recoiling system is then put on-shell in its rest frame.",
3);
static SwitchOption interfaceFinalStateReconOptionRestRecursive
(interfaceFinalStateReconOption,
"RestRecursive",
"As 3 but recursive treated the currently most-off shell,"
" only makes a difference if more than 3 partons.",
4);
static Switch<QTildeReconstructor,unsigned int> interfaceInitialStateReconOption
("InitialStateReconOption",
"Option for the reconstruction of initial state radiation",
&QTildeReconstructor::_initialStateReconOption, 0, false, false);
static SwitchOption interfaceInitialStateReconOptionRapidity
(interfaceInitialStateReconOption,
"Rapidity",
"Preserve shat and rapidity",
0);
static SwitchOption interfaceInitialStateReconOptionLongitudinal
(interfaceInitialStateReconOption,
"Longitudinal",
"Preserve longitudinal momentum",
1);
static SwitchOption interfaceInitialStateReconOptionSofterFraction
(interfaceInitialStateReconOption,
"SofterFraction",
"Preserve the momentum fraction of the parton which has emitted softer.",
2);
}
void QTildeReconstructor::doinit() {
KinematicsReconstructor::doinit();
_noRescale = set<cPDPtr>(_noRescaleVector.begin(),_noRescaleVector.end());
}
bool QTildeReconstructor::
reconstructTimeLikeJet(const tShowerParticlePtr particleJetParent) const {
assert(particleJetParent);
bool emitted=true;
// if this is not a fixed point in the reconstruction
if( !particleJetParent->children().empty() ) {
// if not a reconstruction fixpoint, dig deeper for all children:
for ( ParticleVector::const_iterator cit =
particleJetParent->children().begin();
cit != particleJetParent->children().end(); ++cit )
reconstructTimeLikeJet(dynamic_ptr_cast<ShowerParticlePtr>(*cit));
}
// it is a reconstruction fixpoint, ie kinematical data has to be available
else {
// check if the parent was part of the shower
ShowerParticlePtr jetGrandParent;
if(!particleJetParent->parents().empty())
jetGrandParent= dynamic_ptr_cast<ShowerParticlePtr>
(particleJetParent->parents()[0]);
// update if so
if (jetGrandParent) {
if (jetGrandParent->showerKinematics()) {
if(particleJetParent->id()==_progenitor->id()&&
!_progenitor->data().stable()) {
jetGrandParent->showerKinematics()->reconstructLast(particleJetParent,
_progenitor->mass());
}
else {
jetGrandParent->showerKinematics()->reconstructLast(particleJetParent);
}
}
}
// otherwise
else {
Energy dm = particleJetParent->data().constituentMass();
if (abs(dm-particleJetParent->momentum().m())>0.001*MeV
&&particleJetParent->dataPtr()->stable()
&&particleJetParent->id()!=ParticleID::gamma
&&_noRescale.find(particleJetParent->dataPtr())==_noRescale.end()) {
Lorentz5Momentum dum = particleJetParent->momentum();
if(dm>dum.e()) throw KinematicsReconstructionVeto();
dum.setMass(dm);
dum.rescaleRho();
particleJetParent->set5Momentum(dum);
}
else {
emitted=false;
}
}
}
// recursion has reached an endpoint once, ie we can reconstruct the
// kinematics from the children.
if( !particleJetParent->children().empty() )
particleJetParent->showerKinematics()
->reconstructParent( particleJetParent, particleJetParent->children() );
return emitted;
}
bool QTildeReconstructor::
reconstructHardJets(ShowerTreePtr hard,
const map<tShowerProgenitorPtr,
pair<Energy,double> > & intrinsic,
ShowerInteraction::Type type) const {
_currentTree = hard;
_intrinsic=intrinsic;
// extract the particles from the ShowerTree
vector<ShowerProgenitorPtr> ShowerHardJets=hard->extractProgenitors();
for(unsigned int ix=0;ix<ShowerHardJets.size();++ix) {
_boosts[ShowerHardJets[ix]->progenitor()] = LorentzRotation();
}
try {
// old recon method, using new member functions
if(_reconopt==0) {
reconstructGeneralSystem(ShowerHardJets);
}
// reconstruction based on coloured systems
else {
// identify the colour singlet systems
vector<ColourSingletSystem> systems;
vector<bool> done(ShowerHardJets.size(),false);
for(unsigned int ix=0;ix<ShowerHardJets.size();++ix) {
// if not treated create new system
if(done[ix]) continue;
systems.push_back(ColourSingletSystem(UNDEFINED,ShowerHardJets[ix]));
done[ix] = true;
if(!ShowerHardJets[ix]->progenitor()->coloured()) continue;
// now find the colour connected particles
vector<unsigned int> iloc(1,ix);
do {
vector<unsigned int> temp=findPartners(iloc.back(),ShowerHardJets);
iloc.pop_back();
for(unsigned int iy=0;iy<temp.size();++iy) {
if(!done[temp[iy]]) {
done[temp[iy]] = true;
iloc.push_back(temp[iy]);
systems.back().jets.push_back(ShowerHardJets[temp[iy]]);
}
}
}
while(!iloc.empty());
}
// catagorize the systems
unsigned int nnun(0),nnii(0),nnif(0),nnf(0),nni(0);
for(unsigned int ix=0;ix<systems.size();++ix) {
unsigned int ni(0),nf(0);
for(unsigned int iy=0;iy<systems[ix].jets.size();++iy) {
if(systems[ix].jets[iy]->progenitor()->isFinalState()) ++nf;
else ++ni;
}
// type
// initial-initial
if(ni==2&&nf==0) {
systems[ix].type = II;
++nnii;
}
// initial only
else if(ni==1&&nf==0) {
systems[ix].type = I;
++nni;
}
// initial-final
else if(ni==1&&nf>0) {
systems[ix].type = IF;
++nnif;
}
// final only
else if(ni==0&&nf>0) {
systems[ix].type = F;
++nnf;
}
// otherwise unknown
else {
systems[ix].type = UNDEFINED;
++nnun;
}
}
// now decide what to do
// initial-initial connection and final-state colour singlet systems
LorentzRotation toRest,fromRest;
bool applyBoost(false);
bool general(false);
// Drell-Yan type
if(nnun==0&&nnii==1&&nnif==0&&nnf>0&&nni==0) {
// reconstruct initial-initial system
for(unsigned int ix=0;ix<systems.size();++ix) {
if(systems[ix].type==II)
reconstructInitialInitialSystem(applyBoost,toRest,fromRest,
systems[ix].jets);
}
if(type==ShowerInteraction::QED||
type==ShowerInteraction::Both) {
combineFinalStateSystem(systems);
general=false;
}
}
// DIS and VBF type
else if(nnun==0&&nnii==0&&((nnif==1&&nnf>0&&nni==1)||
(nnif==2&& nni==0))) {
// check these systems can be reconstructed
for(unsigned int ix=0;ix<systems.size();++ix) {
// compute q^2
if(systems[ix].type!=IF) continue;
Lorentz5Momentum q;
for(unsigned int iy=0;iy<systems[ix].jets.size();++iy) {
if(systems[ix].jets[iy]->progenitor()->isFinalState())
q += systems[ix].jets[iy]->progenitor()->momentum();
else
q -= systems[ix].jets[iy]->progenitor()->momentum();
}
q.rescaleMass();
// check above cut
if(abs(q.m())>=_minQ) continue;
if(nnif==1&&nni==1) {
throw KinematicsReconstructionVeto();
}
else {
general = true;
break;
}
}
if(!general) {
for(unsigned int ix=0;ix<systems.size();++ix) {
if(systems[ix].type==IF)
reconstructInitialFinalSystem(systems[ix].jets);
}
}
}
// e+e- type
else if(nnun==0&&nnii==0&&nnif==0&&nnf>0&&nni==2) {
general = type==ShowerInteraction::QED || type == ShowerInteraction::Both;
}
// general type
else {
general = true;
}
// final-state systems except for general recon
if(!general) {
for(unsigned int ix=0;ix<systems.size();++ix) {
if(systems[ix].type==F)
reconstructFinalStateSystem(applyBoost,toRest,fromRest,
systems[ix].jets);
}
}
else {
reconstructGeneralSystem(ShowerHardJets);
}
}
}
catch(KinematicsReconstructionVeto) {
_progenitor=tShowerParticlePtr();
_intrinsic.clear();
_currentTree = tShowerTreePtr();
for(map<tPPtr,LorentzRotation >::const_iterator bit=_boosts.begin();bit!=_boosts.end();++bit) {
LorentzRotation rot = bit->second.inverse();
bit->first->transform(rot);
}
_boosts.clear();
return false;
}
catch (Exception & ex) {
_progenitor=tShowerParticlePtr();
_intrinsic.clear();
_currentTree = tShowerTreePtr();
_boosts.clear();
throw ex;
}
_progenitor=tShowerParticlePtr();
_intrinsic.clear();
// ensure x<1
for(map<ShowerProgenitorPtr,ShowerParticlePtr>::const_iterator
cit=hard->incomingLines().begin();cit!=hard->incomingLines().end();++cit) {
tPPtr parent = cit->first->progenitor();
while (!parent->parents().empty()) {
parent = parent->parents()[0];
}
tPPtr hadron;
if ( cit->first->original()->parents().empty() ) {
hadron = cit->first->original();
}
else {
hadron = cit->first->original()->parents()[0];
}
if( ! (hadron->id() == parent->id() && hadron->children().size() <= 1)
&& parent->momentum().rho() > hadron->momentum().rho()) {
_progenitor=tShowerParticlePtr();
_intrinsic.clear();
_currentTree = tShowerTreePtr();
for(map<tPPtr,LorentzRotation >::const_iterator bit=_boosts.begin();bit!=_boosts.end();++bit) {
LorentzRotation rot = bit->second.inverse();
bit->first->transform(rot);
}
_boosts.clear();
return false;
}
}
_boosts.clear();
_currentTree = tShowerTreePtr();
return true;
}
double
QTildeReconstructor::solveKfactor(const Energy & root_s,
const JetKinVect & jets) const {
Energy2 s = sqr(root_s);
// must be at least two jets
if ( jets.size() < 2) throw KinematicsReconstructionVeto();
// sum of jet masses must be less than roots
if(momConsEq( 0.0, root_s, jets )>ZERO) throw KinematicsReconstructionVeto();
// if two jets simple solution
if ( jets.size() == 2 ) {
static const Energy2 eps = 1.0e-4 * MeV2;
if ( sqr(jets[0].p.x()+jets[1].p.x()) < eps &&
sqr(jets[0].p.y()+jets[1].p.y()) < eps &&
sqr(jets[0].p.z()+jets[1].p.z()) < eps ) {
Energy test = (jets[0].p+jets[1].p).vect().mag();
if(test > 1.0e-4 * MeV) throw KinematicsReconstructionVeto();
if ( jets[0].p.vect().mag2() < eps ) throw KinematicsReconstructionVeto();
Energy2 m1sq(jets[0].q.m2()),m2sq(jets[1].q.m2());
return sqrt( ( sqr(s - m1sq - m2sq) - 4.*m1sq*m2sq )
/(4.*s*jets[0].p.vect().mag2()) );
}
else throw KinematicsReconstructionVeto();
}
// i.e. jets.size() > 2, numerically
// check convergence, if it's a problem maybe use Newton iteration?
else {
double k1 = 0.,k2 = 1.,k = 0.;
if ( momConsEq( k1, root_s, jets ) < ZERO ) {
while ( momConsEq( k2, root_s, jets ) < ZERO ) {
k1 = k2;
k2 *= 2;
}
while ( fabs( (k1 - k2)/(k1 + k2) ) > 1.e-10 ) {
if( momConsEq( k2, root_s, jets ) == ZERO ) {
return k2;
} else {
k = (k1+k2)/2.;
if ( momConsEq( k, root_s, jets ) > ZERO ) {
k2 = k;
} else {
k1 = k;
}
}
}
return k1;
} else throw KinematicsReconstructionVeto();
}
throw KinematicsReconstructionVeto();
}
bool QTildeReconstructor::
reconstructSpaceLikeJet( const tShowerParticlePtr p) const {
bool emitted = true;
tShowerParticlePtr child;
tShowerParticlePtr parent;
if(!p->parents().empty())
parent = dynamic_ptr_cast<ShowerParticlePtr>(p->parents()[0]);
if(parent) {
emitted=true;
reconstructSpaceLikeJet(parent);
}
// if branching reconstruct time-like child
if(p->children().size()==2)
child = dynamic_ptr_cast<ShowerParticlePtr>(p->children()[1]);
if(p->perturbative()==0 && child) {
dynamic_ptr_cast<ShowerParticlePtr>(p->children()[0])->
showerKinematics()->reconstructParent(p,p->children());
if(!child->children().empty()) {
_progenitor=child;
reconstructTimeLikeJet(child);
// calculate the momentum of the particle
Lorentz5Momentum pnew=p->momentum()-child->momentum();
pnew.rescaleMass();
p->children()[0]->set5Momentum(pnew);
}
}
return emitted;
}
Boost QTildeReconstructor::
solveBoostBeta( const double k, const Lorentz5Momentum & newq,
const Lorentz5Momentum & oldp ) {
// try something different, purely numerical first:
// a) boost to rest frame of newq, b) boost with kp/E
Energy q = newq.vect().mag();
Energy2 qs = sqr(q);
Energy2 Q2 = newq.m2();
Energy kp = k*(oldp.vect().mag());
Energy2 kps = sqr(kp);
// usually we take the minus sign, since this boost will be smaller.
// we only require |k \vec p| = |\vec q'| which leaves the sign of
// the boost open but the 'minus' solution gives a smaller boost
// parameter, i.e. the result should be closest to the previous
// result. this is to be changed if we would get many momentum
// conservation violations at the end of the shower from a hard
// process.
double betam = (q*sqrt(qs + Q2) - kp*sqrt(kps + Q2))/(kps + qs + Q2);
// move directly to 'return'
Boost beta = -betam*(k/kp)*oldp.vect();
// note that (k/kp)*oldp.vect() = oldp.vect()/oldp.vect().mag() but cheaper.
// leave this out if it's running properly!
if ( betam >= 0 ) return beta;
else return Boost(0., 0., 0.);
}
bool QTildeReconstructor::
reconstructDecayJets(ShowerTreePtr decay,
ShowerInteraction::Type) const {
_currentTree = decay;
try {
// extract the particles from the ShowerTree
vector<ShowerProgenitorPtr> ShowerHardJets=decay->extractProgenitors();
bool radiated[2]={false,false};
// find the decaying particle and check if particles radiated
ShowerProgenitorPtr initial;
for(unsigned int ix=0;ix<ShowerHardJets.size();++ix) {
// only consider initial-state jets
if(ShowerHardJets[ix]->progenitor()->isFinalState()) {
radiated[1] |=ShowerHardJets[ix]->hasEmitted();
}
else {
initial=ShowerHardJets[ix];
radiated[0]|=ShowerHardJets[ix]->hasEmitted();
}
}
// find boost to the rest frame if needed
Boost boosttorest=-initial->progenitor()->momentum().boostVector();
double gammarest =
initial->progenitor()->momentum().e()/
initial->progenitor()->momentum().mass();
// check if need to boost to rest frame
bool gottaBoost = (boosttorest.mag() > 1e-12);
// if initial state radiation reconstruct the jet and set up the basis vectors
Lorentz5Momentum pjet;
Lorentz5Momentum nvect;
// find the partner
ShowerParticlePtr partner = initial->progenitor()->partner();
Lorentz5Momentum ppartner[2];
if(partner) ppartner[0]=partner->momentum();
// get the n reference vector
if(partner) {
if(initial->progenitor()->showerKinematics()) {
nvect = initial->progenitor()->showerKinematics()->getBasis()[1];
}
else {
Lorentz5Momentum ppartner=initial->progenitor()->partner()->momentum();
if(gottaBoost) ppartner.boost(boosttorest,gammarest);
nvect = Lorentz5Momentum( ZERO,0.5*initial->progenitor()->mass()*
ppartner.vect().unit());
nvect.boost(-boosttorest,gammarest);
}
}
// if ISR
if(radiated[0]) {
// reconstruct the decay jet
reconstructDecayJet(initial->progenitor());
// momentum of decaying particle after ISR
pjet=initial->progenitor()->momentum()
-decay->incomingLines().begin()->second->momentum();
pjet.rescaleMass();
}
// boost initial state jet and basis vector if needed
if(gottaBoost) {
pjet.boost(boosttorest,gammarest);
nvect.boost(boosttorest,gammarest);
ppartner[0].boost(boosttorest,gammarest);
}
// loop over the final-state particles and do the reconstruction
JetKinVect possiblepartners;
JetKinVect jetKinematics;
bool atLeastOnce = radiated[0];
LorentzRotation restboost(boosttorest,gammarest);
Energy inmass(ZERO);
for(unsigned int ix=0;ix<ShowerHardJets.size();++ix) {
// only consider final-state jets
if(!ShowerHardJets[ix]->progenitor()->isFinalState()) {
inmass=ShowerHardJets[ix]->progenitor()->mass();
continue;
}
// do the reconstruction
JetKinStruct tempJetKin;
tempJetKin.parent = ShowerHardJets[ix]->progenitor();
if(ShowerHardJets.size()==2) {
Lorentz5Momentum dum=ShowerHardJets[ix]->progenitor()->momentum();
dum.setMass(inmass);
dum.rescaleRho();
tempJetKin.parent->set5Momentum(dum);
}
tempJetKin.p = ShowerHardJets[ix]->progenitor()->momentum();
if(gottaBoost) tempJetKin.p.boost(boosttorest,gammarest);
_progenitor=tempJetKin.parent;
if(ShowerHardJets[ix]->reconstructed()==ShowerProgenitor::notReconstructed) {
atLeastOnce |= reconstructTimeLikeJet(tempJetKin.parent);
ShowerHardJets[ix]->reconstructed(ShowerProgenitor::done);
}
if(gottaBoost) deepTransform(tempJetKin.parent,restboost);
tempJetKin.q = ShowerHardJets[ix]->progenitor()->momentum();
jetKinematics.push_back(tempJetKin);
}
if(partner) ppartner[1]=partner->momentum();
// calculate the rescaling parameters
double k1,k2;
Lorentz5Momentum qt;
if(!solveDecayKFactor(initial->progenitor()->mass(),nvect,pjet,
jetKinematics,partner,ppartner,k1,k2,qt)) {
_currentTree = tShowerTreePtr();
return false;
}
// apply boosts and rescalings to final-state jets
for(JetKinVect::iterator it = jetKinematics.begin();
it != jetKinematics.end(); ++it) {
LorentzRotation Trafo = LorentzRotation();
if(it->parent!=partner) {
// boost for rescaling
if(atLeastOnce) {
map<tShowerTreePtr,pair<tShowerProgenitorPtr,
tShowerParticlePtr> >::const_iterator tit;
for(tit = _currentTree->treelinks().begin();
tit != _currentTree->treelinks().end();++tit) {
if(tit->second.first && tit->second.second==it->parent)
break;
}
if(it->parent->children().empty()&&!it->parent->spinInfo() &&
tit==_currentTree->treelinks().end()) {
Lorentz5Momentum pnew(k2*it->p.vect(),
sqrt(sqr(k2*it->p.vect().mag())+it->q.mass2()),
it->q.mass());
it->parent->set5Momentum(pnew);
}
else {
// rescaling boost can't ever work in this case
if(k2<0. && it->q.mass()==ZERO)
throw KinematicsReconstructionVeto();
Trafo = solveBoost(k2, it->q, it->p);
}
}
if(gottaBoost) Trafo.boost(-boosttorest,gammarest);
if(atLeastOnce || gottaBoost) deepTransform(it->parent,Trafo);
}
else {
Lorentz5Momentum pnew=ppartner[0];
pnew *=k1;
pnew-=qt;
pnew.setMass(ppartner[1].mass());
pnew.rescaleEnergy();
LorentzRotation Trafo=solveBoost(1.,ppartner[1],pnew);
if(gottaBoost) Trafo.boost(-boosttorest,gammarest);
deepTransform(partner,Trafo);
}
}
}
catch(KinematicsReconstructionVeto) {
_currentTree = tShowerTreePtr();
return false;
}
_currentTree = tShowerTreePtr();
return true;
}
bool QTildeReconstructor::
reconstructDecayJet( const tShowerParticlePtr p) const {
if(p->children().empty()) return false;
tShowerParticlePtr child;
// if branching reconstruct time-like child
child = dynamic_ptr_cast<ShowerParticlePtr>(p->children()[1]);
if(child) {
_progenitor=child;
reconstructTimeLikeJet(child);
// calculate the momentum of the particle
Lorentz5Momentum pnew=p->momentum()-child->momentum();
pnew.rescaleMass();
p->children()[0]->set5Momentum(pnew);
child=dynamic_ptr_cast<ShowerParticlePtr>(p->children()[0]);
reconstructDecayJet(child);
return true;
}
return false;
}
bool QTildeReconstructor::
solveDecayKFactor(Energy mb,
const Lorentz5Momentum & n,
const Lorentz5Momentum & pjet,
const JetKinVect & jetKinematics,
ShowerParticlePtr partner,
Lorentz5Momentum ppartner[2],
double & k1, double & k2,
Lorentz5Momentum & qt) const {
Energy2 pjn = partner ? pjet.vect()*n.vect() : ZERO;
Energy2 pcn = partner ? ppartner[0].vect()*n.vect() : 1.*MeV2;
Energy2 nmag = n.vect().mag2();
Lorentz5Momentum pn = partner ? (pjn/nmag)*n : Lorentz5Momentum();
qt=pjet-pn; qt.setE(ZERO);
Energy2 pt2=qt.vect().mag2();
Energy Ejet = pjet.e();
// magnitudes of the momenta for fast access
vector<Energy2> pmag;
Energy total(Ejet);
for(unsigned int ix=0;ix<jetKinematics.size();++ix) {
pmag.push_back(jetKinematics[ix].p.vect().mag2());
total+=jetKinematics[ix].q.mass();
}
// return if no possible solution
if(total>mb) return false;
Energy2 pcmag=ppartner[0].vect().mag2();
// used newton-raphson to get the rescaling
static const Energy eps=1e-8*GeV;
long double d1(1.),d2(1.);
Energy roots, ea, ec, ds;
unsigned int ix=0;
do {
++ix;
d2 = d1 + pjn/pcn;
roots = Ejet;
ds = ZERO;
for(unsigned int iy=0;iy<jetKinematics.size();++iy) {
if(jetKinematics[iy].parent==partner) continue;
ea = sqrt(sqr(d2)*pmag[iy]+jetKinematics[iy].q.mass2());
roots += ea;
ds += d2/ea*pmag[iy];
}
if(partner) {
ec = sqrt(sqr(d1)*pcmag + pt2 + ppartner[1].mass2());
roots += ec;
ds += d1/ec*pcmag;
}
d1 += (mb-roots)/ds;
d2 = d1 + pjn/pcn;
}
while(abs(mb-roots)>eps && ix<100);
k1=d1;
k2=d2;
// return true if N-R succeed, otherwise false
return ix<100;
}
bool QTildeReconstructor::
deconstructDecayJets(HardTreePtr decay, cEvolverPtr,
ShowerInteraction::Type) const {
// extract the momenta of the particles
vector<Lorentz5Momentum> pin;
vector<Lorentz5Momentum> pout;
// on-shell masses of the decay products
vector<Energy> mon;
Energy mbar(-GeV);
// the hard branchings of the particles
set<HardBranchingPtr>::iterator cit;
set<HardBranchingPtr> branchings=decay->branchings();
// properties of the incoming particle
bool ISR = false;
HardBranchingPtr initial;
Lorentz5Momentum qisr;
// find the incoming particle, both before and after
// any ISR
for(cit=branchings.begin();cit!=branchings.end();++cit){
if((*cit)->status()==HardBranching::Incoming||
(*cit)->status()==HardBranching::Decay) {
// search back up isr if needed
HardBranchingPtr branch = *cit;
while(branch->parent()) branch=branch->parent();
initial=branch;
// momentum or original parent
pin.push_back(branch->branchingParticle()->momentum());
// ISR?
ISR = !branch->branchingParticle()->children().empty();
// ISR momentum
qisr = pin.back()-(**cit).branchingParticle()->momentum();
qisr.rescaleMass();
}
}
assert(pin.size()==1);
// compute boost to rest frame
Boost boostv=-pin[0].boostVector();
// partner for ISR
ShowerParticlePtr partner;
Lorentz5Momentum ppartner;
if(initial->branchingParticle()->partner()) {
partner=initial->branchingParticle()->partner();
ppartner=partner->momentum();
}
// momentum of the decay products
for(cit=branchings.begin();cit!=branchings.end();++cit) {
if((*cit)->status()!=HardBranching::Outgoing) continue;
// find the mass of the particle
// including special treatment for off-shell resonances
// to preserve off-shell mass
Energy mass;
if(!(**cit).branchingParticle()->dataPtr()->stable()) {
HardBranchingPtr branch=*cit;
while(!branch->children().empty()) {
for(unsigned int ix=0;ix<branch->children().size();++ix) {
if(branch->children()[ix]->branchingParticle()->id()==
(**cit).branchingParticle()->id()) {
branch = branch->children()[ix];
continue;
}
}
};
mass = branch->branchingParticle()->mass();
}
else {
mass = (**cit).branchingParticle()->dataPtr()->mass();
}
// if not evolution partner of decaying particle
if((*cit)->branchingParticle()!=partner) {
pout.push_back((*cit)->branchingParticle()->momentum());
mon.push_back(mass);
}
// evolution partner of decaying particle
else {
mbar = mass;
}
}
// boost all the momenta to the rest frame of the decaying particle
for(unsigned int ix=0;ix<pout.size();++ix) pout[ix].boost(boostv);
if(initial->branchingParticle()->partner()) {
ppartner.boost(boostv);
qisr.boost(boostv);
}
// compute the rescaling factors
double k1,k2;
if(!ISR) {
if(partner) {
pout.push_back(ppartner);
mon.push_back(mbar);
}
k1=k2=inverseRescalingFactor(pout,mon,pin[0].mass());
if(partner) {
pout.pop_back();
mon.pop_back();
}
}
else {
if(!inverseDecayRescalingFactor(pout,mon,pin[0].mass(),
ppartner,mbar,k1,k2)) return false;
}
// now calculate the p reference vectors
unsigned int ifinal=0;
for(cit=branchings.begin();cit!=branchings.end();++cit) {
if((**cit).status()!=HardBranching::Outgoing) continue;
// for partners other than colour partner of decaying particle
if((*cit)->branchingParticle()!=partner) {
Lorentz5Momentum pvect = (*cit)->branchingParticle()->momentum();
pvect.boost(boostv);
pvect /= k1;
pvect.setMass(mon[ifinal]);
++ifinal;
pvect.rescaleEnergy();
pvect.boost(-boostv);
(*cit)->pVector(pvect);
(*cit)->showerMomentum(pvect);
}
// for colour partner of decaying particle
else {
Lorentz5Momentum pvect = (*cit)->branchingParticle()->momentum();
pvect.boost(boostv);
Lorentz5Momentum qtotal;
for(unsigned int ix=0;ix<pout.size();++ix) qtotal+=pout[ix];
Lorentz5Momentum qperp =
qisr-(qisr.vect()*qtotal.vect())/(qtotal.vect().mag2())*qtotal;
pvect +=qperp;
pvect /=k2;
pvect.setMass(mbar);
pvect.rescaleEnergy();
pvect.boost(-boostv);
(*cit)->pVector(pvect);
(*cit)->showerMomentum(pvect);
}
}
// // find the evolution partners
// ShowerParticleVector particles;
// particles.push_back((**decay->incoming().begin()).branchingParticle());
// for(cit=branchings.begin();cit!=branchings.end();++cit) {
// if((**cit).status()==HardBranching::Outgoing)
// particles.push_back((*cit)->branchingParticle());
// }
// // partners should
// evolver->showerModel()->partnerFinder()
// ->setInitialEvolutionScales(particles,true,type,false);
// For initial-state if needed
if(initial) {
tShowerParticlePtr newPartner=initial->branchingParticle()->partner();
if(newPartner) {
tHardBranchingPtr branch;
for( set<HardBranchingPtr>::iterator clt = branchings.begin();
clt != branchings.end(); ++clt ) {
if((**clt).branchingParticle()==newPartner) {
initial->colourPartner(*clt);
branch=*clt;
break;
}
}
Lorentz5Momentum pvect = initial->branchingParticle()->momentum();
initial->pVector(pvect);
Lorentz5Momentum ptemp = branch->pVector();
ptemp.boost(boostv);
Lorentz5Momentum nvect = Lorentz5Momentum( ZERO,
0.5*initial->branchingParticle()->mass()*
ptemp.vect().unit());
nvect.boost(-boostv);
initial->nVector(nvect);
}
}
// calculate the reference vectors, then for outgoing particles
for(cit=branchings.begin();cit!=branchings.end();++cit){
if((**cit).status()!=HardBranching::Outgoing) continue;
// find the partner branchings
tShowerParticlePtr newPartner=(*cit)->branchingParticle()->partner();
if(!newPartner) continue;
tHardBranchingPtr branch;
for( set<HardBranchingPtr>::iterator clt = branchings.begin();
clt != branchings.end(); ++clt ) {
if(cit==clt) continue;
if((**clt).branchingParticle()==newPartner) {
(**cit).colourPartner(*clt);
branch=*clt;
break;
}
}
if((**decay->incoming().begin()).branchingParticle()==newPartner) {
(**cit).colourPartner(*decay->incoming().begin());
branch = *decay->incoming().begin();
}
// final-state colour partner
if(branch->status()==HardBranching::Outgoing) {
Boost boost=((*cit)->pVector()+branch->pVector()).findBoostToCM();
Lorentz5Momentum pcm = branch->pVector();
pcm.boost(boost);
Lorentz5Momentum nvect = Lorentz5Momentum(ZERO,pcm.vect());
nvect.boost( -boost);
(*cit)->nVector(nvect);
}
// initial-state colour partner
else {
Boost boost=branch->pVector().findBoostToCM();
Lorentz5Momentum pcm = (*cit)->pVector();
pcm.boost(boost);
Lorentz5Momentum nvect = Lorentz5Momentum( ZERO, -pcm.vect());
nvect.boost( -boost);
(*cit)->nVector(nvect);
}
}
// now compute the new momenta
// and calculate the shower variables
for(cit=branchings.begin();cit!=branchings.end();++cit) {
if((**cit).status()!=HardBranching::Outgoing) continue;
LorentzRotation B=LorentzRotation(-boostv);
LorentzRotation A=LorentzRotation(boostv),R;
if((*cit)->branchingParticle()==partner) {
Lorentz5Momentum qnew;
Energy2 dot=(*cit)->pVector()*(*cit)->nVector();
double beta = 0.5*((*cit)->branchingParticle()->momentum().m2()
-sqr((*cit)->pVector().mass()))/dot;
qnew=(*cit)->pVector()+beta*(*cit)->nVector();
qnew.rescaleMass();
// compute the boost
R=B*solveBoost(A*qnew,A*(*cit)->branchingParticle()->momentum())*A;
}
else {
Lorentz5Momentum qnew;
if((*cit)->branchingParticle()->partner()) {
Energy2 dot=(*cit)->pVector()*(*cit)->nVector();
double beta = 0.5*((*cit)->branchingParticle()->momentum().m2()
-sqr((*cit)->pVector().mass()))/dot;
qnew=(*cit)->pVector()+beta*(*cit)->nVector();
qnew.rescaleMass();
}
else {
qnew = (*cit)->pVector();
}
// compute the boost
R=B*solveBoost(A*qnew,A*(*cit)->branchingParticle()->momentum())*A;
}
// reconstruct the momenta
(*cit)->setMomenta(R,1.0,Lorentz5Momentum());
}
if(initial) {
initial->setMomenta(LorentzRotation(),1.0,Lorentz5Momentum());
}
return true;
}
double QTildeReconstructor::
inverseRescalingFactor(vector<Lorentz5Momentum> pout,
vector<Energy> mon, Energy roots) const {
double lambda=1.;
if(pout.size()==2) {
double mu_q1(pout[0].m()/roots), mu_q2(pout[1].m()/roots);
double mu_p1(mon[0]/roots) , mu_p2(mon[1]/roots);
lambda =
((1.+mu_q1+mu_q2)*(1.-mu_q1-mu_q2)*(mu_q1-1.-mu_q2)*(mu_q2-1.-mu_q1))/
((1.+mu_p1+mu_p2)*(1.-mu_p1-mu_p2)*(mu_p1-1.-mu_p2)*(mu_p2-1.-mu_p1));
if(lambda<0.)
throw Exception() << "Rescaling factor is imaginary in QTildeReconstructor::"
<< "inverseRescalingFactor lambda^2= " << lambda
<< Exception::eventerror;
lambda = sqrt(lambda);
}
else {
unsigned int ntry=0;
// compute magnitudes once for speed
vector<Energy2> pmag;
for(unsigned int ix=0;ix<pout.size();++ix) {
pmag.push_back(pout[ix].vect().mag2());
}
// Newton-Raphson for the rescaling
vector<Energy> root(pout.size());
do {
// compute new energies
Energy sum(ZERO);
for(unsigned int ix=0;ix<pout.size();++ix) {
root[ix] = sqrt(pmag[ix]/sqr(lambda)+sqr(mon[ix]));
sum+=root[ix];
}
// if accuracy reached exit
if(abs(sum/roots-1.)<1e-10) break;
// use Newton-Raphson to compute new guess for lambda
Energy numer(ZERO),denom(ZERO);
for(unsigned int ix=0;ix<pout.size();++ix) {
numer +=root[ix];
denom +=pmag[ix]/root[ix];
}
numer-=roots;
double fact = 1.+sqr(lambda)*numer/denom;
if(fact<0.) fact=0.5;
lambda *=fact;
++ntry;
}
while(ntry<100);
}
if(isnan(lambda))
throw Exception() << "Rescaling factor is nan in QTildeReconstructor::"
<< "inverseRescalingFactor "
<< Exception::eventerror;
return lambda;
}
bool QTildeReconstructor::
deconstructGeneralSystem(HardTreePtr tree,
cEvolverPtr evolver,
ShowerInteraction::Type type) const {
// extract incoming and outgoing particles
ColourSingletShower in,out;
for(set<HardBranchingPtr>::const_iterator it=tree->branchings().begin();
it!=tree->branchings().end();++it) {
if((**it).status()==HardBranching::Incoming) in .jets.push_back(*it);
else out.jets.push_back(*it);
}
LorentzRotation toRest,fromRest;
bool applyBoost(false);
// do the initial-state reconstruction
deconstructInitialInitialSystem(applyBoost,toRest,fromRest,
tree,in.jets,type);
// do the final-state reconstruction
deconstructFinalStateSystem(toRest,fromRest,tree,
out.jets,evolver,type);
// only at this point that we can be sure all the reference vectors
// are correct
for(set<HardBranchingPtr>::const_iterator it=tree->branchings().begin();
it!=tree->branchings().end();++it) {
if((**it).status()==HardBranching::Incoming) continue;
if((**it).branchingParticle()->coloured())
(**it).setMomenta(LorentzRotation(),1.,Lorentz5Momentum(),false);
}
for(set<HardBranchingPtr>::const_iterator it=tree->incoming().begin();
it!=tree->incoming().end();++it) {
(**it).setMomenta(LorentzRotation(),1.,Lorentz5Momentum(),false);
}
return true;
}
bool QTildeReconstructor::deconstructHardJets(HardTreePtr tree,
cEvolverPtr evolver,
ShowerInteraction::Type type) const {
// inverse of old recon method
if(_reconopt==0) {
return deconstructGeneralSystem(tree,evolver,type);
}
// inverse of reconstruction based on coloured systems
else {
// identify the colour singlet systems
vector<ColourSingletShower> systems;
set<HardBranchingPtr> done;
for(set<HardBranchingPtr>::const_iterator it=tree->branchings().begin();
it!=tree->branchings().end();++it) {
// if not treated create new system
if(done.find(*it)!=done.end()) continue;
done.insert(*it);
systems.push_back(ColourSingletShower(UNDEFINED,*it));
if(!(**it).branchingParticle()->coloured()) continue;
// now find the colour connected particles
findPartners(*it,done,tree->branchings(),systems.back().jets);
}
// catagorize the systems
unsigned int nnun(0),nnii(0),nnif(0),nnf(0),nni(0);
for(unsigned int ix=0;ix<systems.size();++ix) {
unsigned int ni(0),nf(0);
for(unsigned int iy=0;iy<systems[ix].jets.size();++iy) {
if(systems[ix].jets[iy]->status()==HardBranching::Outgoing) ++nf;
else ++ni;
}
// type
// initial-initial
if(ni==2&&nf==0) {
systems[ix].type = II;
++nnii;
}
// initial only
else if(ni==1&&nf==0) {
systems[ix].type = I;
++nni;
}
// initial-final
else if(ni==1&&nf>0) {
systems[ix].type = IF;
++nnif;
}
// final only
else if(ni==0&&nf>0) {
systems[ix].type = F;
++nnf;
}
// otherwise unknown
else {
systems[ix].type = UNDEFINED;
++nnun;
}
}
// now decide what to do
LorentzRotation toRest,fromRest;
bool applyBoost(false);
bool general(false);
// initial-initial connection and final-state colour singlet systems
// Drell-Yan type
if(nnun==0&&nnii==1&&nnif==0&&nnf>0&&nni==0) {
// reconstruct initial-initial system
for(unsigned int ix=0;ix<systems.size();++ix) {
if(systems[ix].type==II)
deconstructInitialInitialSystem(applyBoost,toRest,fromRest,tree,
systems[ix].jets,type);
}
if(type==ShowerInteraction::QED||type==ShowerInteraction::Both) {
combineFinalStateShower(systems);
general=false;
}
}
// DIS and VBF type
else if(nnun==0&&nnii==0&&((nnif==1&&nnf>0&&nni==1)||
(nnif==2&& nni==0))) {
for(unsigned int ix=0;ix<systems.size();++ix) {
if(systems[ix].type==IF)
deconstructInitialFinalSystem(tree,systems[ix].jets,evolver,type);
}
}
// e+e- type
else if(nnun==0&&nnii==0&&nnif==0&&nnf>0&&nni==2) {
// only FS needed
// but need to boost to rest frame if QED ISR
Lorentz5Momentum ptotal;
for(unsigned int ix=0;ix<systems.size();++ix) {
if(systems[ix].type==I)
ptotal += systems[ix].jets[0]->branchingParticle()->momentum();
}
toRest = LorentzRotation(ptotal.findBoostToCM());
fromRest = toRest;
fromRest.invert();
if(type==ShowerInteraction::QED||type==ShowerInteraction::Both) {
combineFinalStateShower(systems);
general=false;
}
}
// general type
else {
general = true;
}
// final-state systems except for general recon
if(!general) {
for(unsigned int ix=0;ix<systems.size();++ix) {
if(systems[ix].type==F)
deconstructFinalStateSystem(toRest,fromRest,tree,
systems[ix].jets,evolver,type);
}
// only at this point that we can be sure all the reference vectors
// are correct
for(set<HardBranchingPtr>::const_iterator it=tree->branchings().begin();
it!=tree->branchings().end();++it) {
if((**it).status()==HardBranching::Incoming) continue;
if((**it).branchingParticle()->coloured())
(**it).setMomenta(LorentzRotation(),1.,Lorentz5Momentum(),false);
}
for(set<HardBranchingPtr>::const_iterator it=tree->incoming().begin();
it!=tree->incoming().end();++it) {
(**it).setMomenta(LorentzRotation(),1.,Lorentz5Momentum(),false);
}
return true;
}
else {
return deconstructGeneralSystem(tree,evolver,type);
}
return true;
}
}
vector<unsigned int> QTildeReconstructor::
findPartners(unsigned int iloc ,
vector<ShowerProgenitorPtr> jets) const {
vector<unsigned int> output;
for(unsigned int iy=0;iy<jets.size();++iy) {
if(!jets[iy]->progenitor()->data().coloured()||iy==iloc) continue;
bool isPartner = false;
// both in either initial or final state
if(jets[iloc]->progenitor()->isFinalState()!=jets[iy]->progenitor()->isFinalState()) {
//loop over all the colours of both
for(unsigned int ix=0; ix<CLSIZE(jets[iloc]); ++ix){
for(unsigned int jx=0; jx<CLSIZE(jets[iy]); ++jx){
if(CL(jets[iloc],ix) && CL(jets[iloc],ix)==CL(jets[iy],jx))
isPartner = true;
}
}
if(!isPartner){
//loop over anti colours of both
for(unsigned int ix=0; ix<ACLSIZE(jets[iloc]); ++ix){
for(unsigned int jx=0; jx<ACLSIZE(jets[iy]); ++jx){
if(ACL(jets[iloc],ix) && ACL(jets[iloc],ix)==ACL(jets[iy],jx))
isPartner = true;
}
}
}
}
else{
//loop over the colours of the first and the anti-colours of the other
for(unsigned int ix=0; ix<CLSIZE(jets[iloc]); ++ix){
for(unsigned int jx=0; jx<ACLSIZE(jets[iy]); ++jx){
if(CL(jets[iloc],ix) && CL(jets[iloc],ix)==ACL(jets[iy],jx))
isPartner = true;
}
}
if(!isPartner){
//loop over the anti-colours of the first and the colours of the other
for(unsigned int ix=0; ix<ACLSIZE(jets[iloc]); ++ix){
for(unsigned int jx=0; jx<CLSIZE(jets[iy]); jx++){
if(ACL(jets[iloc],ix) && ACL(jets[iloc],ix)==CL(jets[iy],jx))
isPartner = true;
}
}
}
}
// special for sources/sinks
if(jets[iloc]->progenitor()->colourLine()) {
if(jets[iloc]->progenitor()->colourLine()->sourceNeighbours().first) {
tColinePair lines = jets[iloc]->progenitor()->colourLine()->sourceNeighbours();
if(lines.first == jets[iy]->progenitor()-> colourLine() ||
lines.first == jets[iy]->progenitor()-> colourLine() ||
lines.second == jets[iy]->progenitor()->antiColourLine() ||
lines.second == jets[iy]->progenitor()->antiColourLine())
isPartner = true;
}
if(jets[iloc]->progenitor()->colourLine()->sinkNeighbours().first) {
tColinePair lines = jets[iloc]->progenitor()->colourLine()->sinkNeighbours();
if(lines.first == jets[iy]->progenitor()-> colourLine() ||
lines.first == jets[iy]->progenitor()-> colourLine() ||
lines.second == jets[iy]->progenitor()->antiColourLine() ||
lines.second == jets[iy]->progenitor()->antiColourLine())
isPartner = true;
}
}
if(jets[iloc]->progenitor()->antiColourLine()) {
if(jets[iloc]->progenitor()->antiColourLine()->sourceNeighbours().first) {
tColinePair lines = jets[iloc]->progenitor()->antiColourLine()->sourceNeighbours();
if(lines.first == jets[iy]->progenitor()-> colourLine() ||
lines.first == jets[iy]->progenitor()-> colourLine() ||
lines.second == jets[iy]->progenitor()->antiColourLine() ||
lines.second == jets[iy]->progenitor()->antiColourLine())
isPartner = true;
}
if(jets[iloc]->progenitor()->antiColourLine()->sinkNeighbours().first) {
tColinePair lines = jets[iloc]->progenitor()->antiColourLine()->sinkNeighbours();
if(lines.first == jets[iy]->progenitor()-> colourLine() ||
lines.first == jets[iy]->progenitor()-> colourLine() ||
lines.second == jets[iy]->progenitor()->antiColourLine() ||
lines.second == jets[iy]->progenitor()->antiColourLine())
isPartner = true;
}
}
if(isPartner)
output.push_back(iy);
}
return output;
}
void QTildeReconstructor::
reconstructInitialFinalSystem(vector<ShowerProgenitorPtr> jets) const {
Lorentz5Momentum pin[2],pout[2],pbeam;
for(unsigned int ix=0;ix<jets.size();++ix) {
// final-state parton
if(jets[ix]->progenitor()->isFinalState()) {
pout[0] +=jets[ix]->progenitor()->momentum();
_progenitor = jets[ix]->progenitor();
if(jets[ix]->reconstructed()==ShowerProgenitor::notReconstructed) {
reconstructTimeLikeJet(jets[ix]->progenitor());
jets[ix]->reconstructed(ShowerProgenitor::done);
}
}
// initial-state parton
else {
pin[0] +=jets[ix]->progenitor()->momentum();
if(jets[ix]->progenitor()->showerKinematics()) {
pbeam = jets[ix]->progenitor()->x()*jets[ix]->progenitor()->showerKinematics()->getBasis()[0];
}
else {
pbeam = jets[ix]->progenitor()->momentum();
}
if(jets[ix]->reconstructed()==ShowerProgenitor::notReconstructed) {
reconstructSpaceLikeJet(jets[ix]->progenitor());
jets[ix]->reconstructed(ShowerProgenitor::done);
}
assert(!jets[ix]->original()->parents().empty());
}
}
// add intrinsic pt if needed
addIntrinsicPt(jets);
// momenta after showering
for(unsigned int ix=0;ix<jets.size();++ix) {
if(jets[ix]->progenitor()->isFinalState())
pout[1] += jets[ix]->progenitor()->momentum();
else
pin[1] += jets[ix]->progenitor()->momentum();
}
// work out the boost to the Breit frame
Lorentz5Momentum pa = pout[0]-pin[0];
Axis axis(pa.vect().unit());
LorentzRotation rot;
double sinth(sqrt(sqr(axis.x())+sqr(axis.y())));
if ( sinth > 1.e-9 )
rot.setRotate(-acos(axis.z()),Axis(-axis.y()/sinth,axis.x()/sinth,0.));
rot.rotateX(Constants::pi);
rot.boostZ( pa.e()/pa.vect().mag());
Lorentz5Momentum ptemp=rot*pbeam;
Boost trans = -1./ptemp.e()*ptemp.vect();
trans.setZ(0.);
if ( trans.mag2() - 1. >= 0. ) throw KinematicsReconstructionVeto();
rot.boost(trans);
pa *=rot;
// project and calculate rescaling
// reference vectors
Lorentz5Momentum n1(ZERO,ZERO,-pa.z(),-pa.z());
Lorentz5Momentum n2(ZERO,ZERO, pa.z(),-pa.z());
Energy2 n1n2 = n1*n2;
// decompose the momenta
Lorentz5Momentum qbp=rot*pin[1],qcp= rot*pout[1];
double a[2],b[2];
a[0] = n2*qbp/n1n2;
b[0] = n1*qbp/n1n2;
Lorentz5Momentum qperp = qbp-a[0]*n1-b[0]*n2;
b[1] = 0.5;
a[1] = 0.5*(qcp.m2()-qperp.m2())/n1n2/b[1];
double kb;
if(a[0]!=0.) {
double A(0.5*a[0]),B(b[0]*a[0]-a[1]*b[1]-0.25),C(-0.5*b[0]);
if(sqr(B)-4.*A*C<0.) throw KinematicsReconstructionVeto();
kb = 0.5*(-B+sqrt(sqr(B)-4.*A*C))/A;
}
else {
kb = 0.5*b[0]/(b[0]*a[0]-a[1]*b[1]-0.25);
}
// changed to improve stability
if(kb==0.) throw KinematicsReconstructionVeto();
double kc = (a[1]>b[1]) ? (a[0]*kb-0.5)/a[1] : b[1]/(0.5+b[0]/kb);
if(kc==0.) throw KinematicsReconstructionVeto();
Lorentz5Momentum pnew[2] = { a[0]*kb*n1+b[0]/kb*n2+qperp,
a[1]*kc*n1+b[1]/kc*n2+qperp};
LorentzRotation rotinv=rot.inverse();
for(unsigned int ix=0;ix<jets.size();++ix) {
if(jets[ix]->progenitor()->isFinalState()) {
deepTransform(jets[ix]->progenitor(),rot);
deepTransform(jets[ix]->progenitor(),solveBoost(pnew[1],qcp));
deepTransform(jets[ix]->progenitor(),rotinv);
}
else {
tPPtr parent;
boostChain(jets[ix]->progenitor(),rot,parent);
boostChain(jets[ix]->progenitor(),solveBoostZ(pnew[0],qbp),parent);
boostChain(jets[ix]->progenitor(),rotinv,parent);
}
}
}
bool QTildeReconstructor::addIntrinsicPt(vector<ShowerProgenitorPtr> jets) const {
bool added=false;
// add the intrinsic pt if needed
for(unsigned int ix=0;ix<jets.size();++ix) {
// only for initial-state particles which haven't radiated
if(jets[ix]->progenitor()->isFinalState()||
jets[ix]->hasEmitted()) continue;
if(_intrinsic.find(jets[ix])==_intrinsic.end()) continue;
pair<Energy,double> pt=_intrinsic[jets[ix]];
Energy etemp = jets[ix]->original()->parents()[0]->momentum().z();
Lorentz5Momentum
p_basis(ZERO, ZERO, etemp, abs(etemp)),
n_basis(ZERO, ZERO,-etemp, abs(etemp));
double alpha = jets[ix]->progenitor()->x();
double beta = 0.5*(sqr(jets[ix]->progenitor()->data().mass())+
sqr(pt.first))/alpha/(p_basis*n_basis);
Lorentz5Momentum pnew=alpha*p_basis+beta*n_basis;
pnew.setX(pt.first*cos(pt.second));
pnew.setY(pt.first*sin(pt.second));
pnew.rescaleMass();
jets[ix]->progenitor()->set5Momentum(pnew);
added = true;
}
return added;
}
LorentzRotation QTildeReconstructor::
solveBoost(const double k, const Lorentz5Momentum & newq,
const Lorentz5Momentum & oldp ) const {
Energy q = newq.vect().mag();
Energy2 qs = sqr(q);
Energy2 Q2 = newq.mass2();
Energy kp = k*(oldp.vect().mag());
Energy2 kps = sqr(kp);
double betam = (q*newq.e() - kp*sqrt(kps + Q2))/(kps + qs + Q2);
if ( abs(betam) - 1. >= 0. ) throw KinematicsReconstructionVeto();
Boost beta = -betam*(k/kp)*oldp.vect();
double gamma = 0.;
if(Q2/sqr(oldp.e())>1e-4) {
if(betam<0.5) {
gamma = 1./sqrt(1.-sqr(betam));
}
else {
gamma = ( kps+ qs + Q2)/
sqrt(2.*kps*qs + kps*Q2 + qs*Q2 + sqr(Q2) + 2.*q*newq.e()*kp*sqrt(kps + Q2));
}
}
else {
if(k>0) {
gamma = 4.*kps*qs/sqr(kps +qs) + 2.*sqr(kps-qs)*Q2/pow<3,1>(kps +qs)
- 0.25*( sqr(kps) + 14.*kps*qs + sqr(qs))*sqr(kps-qs)/(pow<4,1>(kps +qs)*kps*qs)*sqr(Q2);
}
else {
gamma = 0.25*sqr(Q2)/(kps*qs)*(1. - 0.5*(kps+qs)/(kps*qs)*Q2);
}
gamma = 1./sqrt(gamma);
}
// note that (k/kp)*oldp.vect() = oldp.vect()/oldp.vect().mag() but cheaper.
ThreeVector<Energy2> ax = newq.vect().cross( oldp.vect() );
double delta = newq.vect().angle( oldp.vect() );
LorentzRotation R;
using Constants::pi;
Energy2 scale1 = sqr(newq.x())+ sqr(newq.y())+sqr(newq.z());
Energy2 scale2 = sqr(oldp.x())+ sqr(oldp.y())+sqr(oldp.z());
if ( ax.mag2()/scale1/scale2 > 1e-28 ) {
R.rotate( delta, unitVector(ax) ).boost( beta , gamma );
}
else if(abs(delta-pi)/pi < 0.001) {
double phi=2.*pi*UseRandom::rnd();
Axis axis(cos(phi),sin(phi),0.);
axis.rotateUz(newq.vect().unit());
R.rotate(delta,axis).boost( beta , gamma );
}
else {
R.boost( beta , gamma );
}
return R;
}
LorentzRotation QTildeReconstructor::solveBoost(const Lorentz5Momentum & q,
const Lorentz5Momentum & p ) const {
Energy modp = p.vect().mag();
Energy modq = q.vect().mag();
double betam = (p.e()*modp-q.e()*modq)/(sqr(modq)+sqr(modp)+p.mass2());
if ( abs(betam)-1. >= 0. ) throw KinematicsReconstructionVeto();
Boost beta = -betam*q.vect().unit();
ThreeVector<Energy2> ax = p.vect().cross( q.vect() );
double delta = p.vect().angle( q.vect() );
LorentzRotation R;
using Constants::pi;
if ( beta.mag2() - 1. >= 0. ) throw KinematicsReconstructionVeto();
if ( ax.mag2()/GeV2/MeV2 > 1e-16 ) {
R.rotate( delta, unitVector(ax) ).boost( beta );
}
else {
R.boost( beta );
}
return R;
}
LorentzRotation QTildeReconstructor::solveBoostZ(const Lorentz5Momentum & q,
const Lorentz5Momentum & p ) const {
static const Energy2 eps2 = 1e-8*GeV2;
static const Energy eps = 1e-4 *GeV;
LorentzRotation R;
double beta;
Energy2 den = (p.t()*q.t()-p.z()*q.z());
Energy2 num = -(p.z()*q.t()-q.z()*p.t());
if(abs(den)<eps2||abs(num)<eps2) {
if(abs(p.t()-abs(p.z()))<eps&&abs(q.t()-abs(q.z()))<eps) {
double ratio = sqr(q.t()/p.t());
beta = -(1.-ratio)/(1.+ratio);
}
else {
beta=0.;
}
}
else {
beta = num/den;
}
if ( abs(beta) - 1. >= 0. ) throw KinematicsReconstructionVeto();
R.boostZ(beta);
Lorentz5Momentum ptest = R*p;
if(ptest.z()/q.z() < 0. || ptest.t()/q.t() < 0. ) {
throw KinematicsReconstructionVeto();
}
return R;
}
void QTildeReconstructor::
reconstructFinalStateSystem(bool applyBoost,
const LorentzRotation & toRest,
const LorentzRotation & fromRest,
vector<ShowerProgenitorPtr> jets) const {
LorentzRotation trans = applyBoost? toRest : LorentzRotation();
// special for case of individual particle
if(jets.size()==1) {
trans.transform(fromRest);
deepTransform(jets[0]->progenitor(),trans);
return;
}
bool radiated(false);
// find the hard process centre-of-mass energy
Lorentz5Momentum pcm;
// check if radiated and calculate total momentum
for(unsigned int ix=0;ix<jets.size();++ix) {
radiated |=jets[ix]->hasEmitted();
pcm += jets[ix]->progenitor()->momentum();
}
if(applyBoost) pcm *= trans;
// check if in CMF frame
Boost beta_cm = pcm.findBoostToCM();
bool gottaBoost(false);
if(beta_cm.mag() > 1e-12) {
gottaBoost = true;
trans.boost(beta_cm);
}
// collection of pointers to initial hard particle and jet momenta
// for final boosts
JetKinVect jetKinematics;
vector<ShowerProgenitorPtr>::const_iterator cit;
for(cit = jets.begin(); cit != jets.end(); cit++) {
JetKinStruct tempJetKin;
tempJetKin.parent = (*cit)->progenitor();
if(applyBoost || gottaBoost) {
deepTransform(tempJetKin.parent,trans);
}
tempJetKin.p = (*cit)->progenitor()->momentum();
_progenitor=tempJetKin.parent;
if((**cit).reconstructed()==ShowerProgenitor::notReconstructed) {
radiated |= reconstructTimeLikeJet((*cit)->progenitor());
(**cit).reconstructed(ShowerProgenitor::done);
}
else {
radiated |= !(*cit)->progenitor()->children().empty();
}
tempJetKin.q = (*cit)->progenitor()->momentum();
jetKinematics.push_back(tempJetKin);
}
// default option rescale everything with the same factor
if( _finalStateReconOption == 0 || jetKinematics.size() <= 2 ) {
// find the rescaling factor
double k = 0.0;
if(radiated) {
k = solveKfactor(pcm.m(), jetKinematics);
// perform the rescaling and boosts
for(JetKinVect::iterator it = jetKinematics.begin();
it != jetKinematics.end(); ++it) {
LorentzRotation Trafo = solveBoost(k, it->q, it->p);
deepTransform(it->parent,Trafo);
}
}
}
// different treatment of most off-shell
else if ( _finalStateReconOption <= 4 ) {
// sort the jets by virtuality
std::sort(jetKinematics.begin(),jetKinematics.end(),JetOrdering());
// Bryan's procedures from FORTRAN
if( _finalStateReconOption <=2 ) {
// loop over the off-shell partons, _finalStateReconOption==1 only first ==2 all
JetKinVect::const_iterator jend = _finalStateReconOption==1 ? jetKinematics.begin()+1 : jetKinematics.end();
for(JetKinVect::const_iterator jit=jetKinematics.begin(); jit!=jend;++jit) {
// calculate the 4-momentum of the recoiling system
Lorentz5Momentum psum;
bool done = true;
for(JetKinVect::const_iterator it=jetKinematics.begin();it!=jetKinematics.end();++it) {
if(it==jit) {
done = false;
continue;
}
// first option put on-shell and sum 4-momenta
if( _finalStateReconOption == 1 ) {
LorentzRotation Trafo = solveBoost(1., it->q, it->p);
deepTransform(it->parent,Trafo);
psum += it->parent->momentum();
}
// second option, sum momenta
else {
// already rescaled
if(done) psum += it->parent->momentum();
// still needs to be rescaled
else psum += it->p;
}
}
// set the mass
psum.rescaleMass();
// calculate the 3-momentum rescaling factor
Energy2 s(pcm.m2());
Energy2 m1sq(jit->q.m2()),m2sq(psum.m2());
Energy4 num = sqr(s - m1sq - m2sq) - 4.*m1sq*m2sq;
if(num<ZERO) throw KinematicsReconstructionVeto();
double k = sqrt( num / (4.*s*jit->p.vect().mag2()) );
// boost the off-shell parton
LorentzRotation B1 = solveBoost(k, jit->q, jit->p);
deepTransform(jit->parent,B1);
// boost everything else to rescale
LorentzRotation B2 = solveBoost(k, psum, psum);
for(JetKinVect::iterator it=jetKinematics.begin();it!=jetKinematics.end();++it) {
if(it==jit) continue;
deepTransform(it->parent,B2);
it->p *= B2;
it->q *= B2;
}
}
}
// Peter's C++ procedures
else {
reconstructFinalFinalOffShell(jetKinematics,pcm.m2(), _finalStateReconOption == 4);
}
}
else
assert(false);
// apply the final boosts
if(gottaBoost || applyBoost) {
LorentzRotation finalBoosts;
if(gottaBoost) finalBoosts.boost(-beta_cm);
if(applyBoost) finalBoosts.transform(fromRest);
for(JetKinVect::iterator it = jetKinematics.begin();
it != jetKinematics.end(); ++it) {
deepTransform(it->parent,finalBoosts);
}
}
}
void QTildeReconstructor::
reconstructInitialInitialSystem(bool & applyBoost,
LorentzRotation & toRest,
LorentzRotation & fromRest,
vector<ShowerProgenitorPtr> jets) const {
bool radiated = false;
Lorentz5Momentum pcm;
// check whether particles radiated and calculate total momentum
for( unsigned int ix = 0; ix < jets.size(); ++ix ) {
radiated |= jets[ix]->hasEmitted();
pcm += jets[ix]->progenitor()->momentum();
}
pcm.rescaleMass();
// check if intrinsic pt to be added
radiated |= !_intrinsic.empty();
// if no radiation return
if(!radiated) return;
// initial state shuffling
applyBoost=false;
vector<Lorentz5Momentum> p, pq, p_in;
vector<Energy> pts;
for(unsigned int ix=0;ix<jets.size();++ix) {
// at momentum to vector
p_in.push_back(jets[ix]->progenitor()->momentum());
// reconstruct the jet
if(jets[ix]->reconstructed()==ShowerProgenitor::notReconstructed) {
radiated |= reconstructSpaceLikeJet(jets[ix]->progenitor());
jets[ix]->reconstructed(ShowerProgenitor::done);
}
assert(!jets[ix]->original()->parents().empty());
Energy etemp = jets[ix]->original()->parents()[0]->momentum().z();
Lorentz5Momentum ptemp = Lorentz5Momentum(ZERO, ZERO, etemp, abs(etemp));
pq.push_back(ptemp);
pts.push_back(jets[ix]->highestpT());
}
// add the intrinsic pt if needed
radiated |=addIntrinsicPt(jets);
for(unsigned int ix=0;ix<jets.size();++ix) {
p.push_back(jets[ix]->progenitor()->momentum());
}
double x1 = p_in[0].z()/pq[0].z();
double x2 = p_in[1].z()/pq[1].z();
Energy MDY = (p_in[0] + p_in[1]).m();
vector<double> beta=initialStateRescaling(x1,x2,MDY,p,pq,pts);
// if not need don't apply boosts
if(!(radiated && p.size() == 2 && pq.size() == 2)) return;
applyBoost=true;
// apply the boosts
Lorentz5Momentum newcmf;
for(unsigned int ix=0;ix<jets.size();++ix) {
tPPtr toBoost = jets[ix]->progenitor();
Boost betaboost(0, 0, beta[ix]);
tPPtr parent;
- boostChain(toBoost, LorentzRotation(betaboost),parent);
+ boostChain(toBoost, LorentzRotation(0.,0.,beta[ix]),parent);
if(parent->momentum().e()/pq[ix].e()>1.||
parent->momentum().z()/pq[ix].z()>1.) throw KinematicsReconstructionVeto();
newcmf+=toBoost->momentum();
}
if(newcmf.m()<ZERO||newcmf.e()<ZERO) throw KinematicsReconstructionVeto();
// do one boost
if(_initialBoost==0) {
toRest = LorentzRotation(pcm.findBoostToCM());
fromRest = LorentzRotation(newcmf.boostVector());
}
else if(_initialBoost==1) {
// boost to rest frame
// first transverse
toRest = Boost(-pcm.x()/pcm.t(),-pcm.y()/pcm.t(),0.);
// then longitudinal
double beta = pcm.z()/sqrt(pcm.m2()+sqr(pcm.z()));
toRest.boost((Boost(0.,0.,-beta)));
// boost from rest frame
// first apply longitudinal boost
beta = newcmf.z()/sqrt(newcmf.m2()+sqr(newcmf.z()));
fromRest=LorentzRotation(Boost(0.,0.,beta));
// then transverse one
fromRest.boost(Boost(newcmf.x()/newcmf.t(),
newcmf.y()/newcmf.t(),0.));
}
else
assert(false);
}
void QTildeReconstructor::
deconstructInitialInitialSystem(bool & applyBoost,
LorentzRotation & toRest,
LorentzRotation & fromRest,
HardTreePtr tree,
vector<HardBranchingPtr> jets,
ShowerInteraction::Type) const {
// get the momenta of the particles
vector<Lorentz5Momentum> pin;
vector<Lorentz5Momentum> pq;
vector<HardBranchingPtr>::iterator cit;
for(cit=jets.begin();cit!=jets.end();++cit) {
pin.push_back((*cit)->branchingParticle()->momentum());
Energy etemp = (*cit)->beam()->momentum().z();
pq.push_back(Lorentz5Momentum(ZERO, ZERO,etemp, abs(etemp)));
}
bool order = (*tree->incoming().begin())->beam()->momentum().z()/pq[0].z()<0.;
assert(pin.size()==2);
// decompose the momenta
double alpha[2],beta[2];
Energy2 p12=pq[0]*pq[1];
Lorentz5Momentum pt[2];
for(unsigned int ix=0;ix<2;++ix) {
alpha[ix] = pin[ix]*pq[1]/p12;
beta [ix] = pin[ix]*pq[0]/p12;
pt[ix] = pin[ix]-alpha[ix]*pq[0]-beta[ix]*pq[1];
}
// parton level centre-of-mass
Lorentz5Momentum pcm=pin[0]+pin[1];
pcm.rescaleMass();
double rap=pcm.rapidity();
// hadron level cmf
Energy2 s = (pq[0] +pq[1] ).m2();
// calculate the x values
assert(pcm.mass2()>ZERO);
double x0 = sqrt(pcm.mass2()/s*exp(2.*rap));
double x[2]={x0, pcm.mass2()/s/x0};
if(pq[0].z()<ZERO) swap(x[0],x[1]);
double k1=alpha[0]/x[0],k2=beta[1]/x[1];
double alphanew[2]={alpha[0]/k1,alpha[1]*k2};
double betanew [2]={beta [0]*k1,beta [1]/k2};
double boost[2];
for(unsigned int ix=0;ix<2;++ix) {
boost[ix] = getBeta(alpha [ix]+beta [ix], alpha[ix] -beta [ix],
alphanew[ix]+betanew[ix], alphanew[ix]-betanew[ix]);
if (pq[0].z() > ZERO) beta[ix]*=-1.;
}
// apply the boost the the particles
// first incoming particle
if(order) swap(pq[0],pq[1]);
// now apply the boosts
Boost betaboost(0.,0.,-boost[0]);
LorentzRotation R;
R.boost(betaboost);
set<HardBranchingPtr>::const_iterator cjt=tree->incoming().begin();
(*cjt)->pVector(pq[0]);
(*cjt)->nVector(pq[1]);
(*cjt)->setMomenta(R,1.,Lorentz5Momentum());
// second incoming particle
betaboost = Boost(0.,0.,-boost[1]);
R=LorentzRotation(betaboost);
++cjt;
(*cjt)->pVector(pq[1]);
(*cjt)->nVector(pq[0]);
(*cjt)->setMomenta(R,1.,Lorentz5Momentum());
jets[0]->showerMomentum(x[0]*jets[0]->pVector());
jets[1]->showerMomentum(x[1]*jets[1]->pVector());
// and calculate the boosts
applyBoost=true;
// do one boost
if(_initialBoost==0) {
toRest = LorentzRotation(-pcm.boostVector());
}
else if(_initialBoost==1) {
// first the transverse boost
Energy pT = sqrt(sqr(pcm.x())+sqr(pcm.y()));
double beta = -pT/pcm.t();
toRest=LorentzRotation(Boost(beta*pcm.x()/pT,beta*pcm.y()/pT,0.));
// the longitudinal
beta = pcm.z()/sqrt(pcm.m2()+sqr(pcm.z()));
toRest.boost(Boost(0.,0.,-beta));
}
else
assert(false);
fromRest = LorentzRotation((jets[0]->showerMomentum()+
jets[1]->showerMomentum()).boostVector());
}
void QTildeReconstructor::
deconstructFinalStateSystem(const LorentzRotation & toRest,
const LorentzRotation & fromRest,
HardTreePtr tree, vector<HardBranchingPtr> jets,
cEvolverPtr evolver,
ShowerInteraction::Type type) const {
if(jets.size()==1) {
LorentzRotation R(toRest);
R.transform(fromRest);
// \todo What does this do? tree->showerRot( R );
jets[0]->original(R*jets[0]->branchingParticle()->momentum());
jets[0]->showerMomentum(R*jets[0]->branchingParticle()->momentum());
// find the colour partners
ShowerParticleVector particles;
vector<Lorentz5Momentum> ptemp;
set<HardBranchingPtr>::const_iterator cjt;
for(cjt=tree->branchings().begin();cjt!=tree->branchings().end();++cjt) {
ptemp.push_back((**cjt).branchingParticle()->momentum());
(**cjt).branchingParticle()->set5Momentum((**cjt).showerMomentum());
particles.push_back((**cjt).branchingParticle());
}
evolver->showerModel()->partnerFinder()
->setInitialEvolutionScales(particles,false,type,false);
// calculate the reference vectors
unsigned int iloc(0);
set<HardBranchingPtr>::iterator clt;
for(cjt=tree->branchings().begin();cjt!=tree->branchings().end();++cjt) {
// reset the momentum
(**cjt).branchingParticle()->set5Momentum(ptemp[iloc]);
++iloc;
// sort out the partners
tShowerParticlePtr partner =
(*cjt)->branchingParticle()->partner();
if(!partner) continue;
for(clt=tree->branchings().begin();clt!=tree->branchings().end();++clt) {
if((**clt).branchingParticle()==partner) {
(**cjt).colourPartner(*clt);
break;
}
}
tHardBranchingPtr branch;
for(clt=tree->branchings().begin();clt!=tree->branchings().end();++clt) {
if(clt==cjt) continue;
if((*clt)->branchingParticle()==partner) {
branch=*clt;
break;
}
}
}
return;
}
vector<HardBranchingPtr>::iterator cit;
vector<Lorentz5Momentum> pout;
vector<Energy> mon;
for(cit=jets.begin();cit!=jets.end();++cit) {
pout.push_back((*cit)->branchingParticle()->momentum());
mon.push_back(findMass(*cit));
}
// boost all the momenta to the rest frame of the decaying particle
Lorentz5Momentum pin;
for(unsigned int ix=0;ix<pout.size();++ix) {
pout[ix].transform(toRest);
pin += pout[ix];
}
pin.rescaleMass();
// rescaling factor
double lambda=inverseRescalingFactor(pout,mon,pin.mass());
if (lambda< 1.e-10) throw KinematicsReconstructionVeto();
// now calculate the p reference vectors
for(unsigned int ix=0;ix<jets.size();++ix) {
Lorentz5Momentum pvect = jets[ix]->branchingParticle()->momentum();
pvect.transform(toRest);
pvect /= lambda;
pvect.setMass(mon[ix]);
pvect.rescaleEnergy();
pvect.transform(fromRest);
jets[ix]->pVector(pvect);
jets[ix]->showerMomentum(pvect);
}
// find the colour partners
ShowerParticleVector particles;
vector<Lorentz5Momentum> ptemp;
set<HardBranchingPtr>::const_iterator cjt;
for(cjt=tree->branchings().begin();cjt!=tree->branchings().end();++cjt) {
ptemp.push_back((**cjt).branchingParticle()->momentum());
(**cjt).branchingParticle()->set5Momentum((**cjt).showerMomentum());
particles.push_back((**cjt).branchingParticle());
}
evolver->showerModel()->partnerFinder()
->setInitialEvolutionScales(particles,false,type,false);
// calculate the reference vectors
unsigned int iloc(0);
set<HardBranchingPtr>::iterator clt;
for(cjt=tree->branchings().begin();cjt!=tree->branchings().end();++cjt) {
// reset the momentum
(**cjt).branchingParticle()->set5Momentum(ptemp[iloc]);
++iloc;
}
for(cjt=tree->branchings().begin();cjt!=tree->branchings().end();++cjt) {
// sort out the partners
tShowerParticlePtr partner =
(*cjt)->branchingParticle()->partner();
if(!partner) continue;
for(clt=tree->branchings().begin();clt!=tree->branchings().end();++clt) {
if((**clt).branchingParticle()==partner) {
(**cjt).colourPartner(*clt);
break;
}
}
tHardBranchingPtr branch;
for(clt=tree->branchings().begin();clt!=tree->branchings().end();++clt) {
if(clt==cjt) continue;
if((*clt)->branchingParticle()==partner) {
branch=*clt;
break;
}
}
// compute the reference vectors
// both incoming, should all ready be done
if((**cjt).status()==HardBranching::Incoming &&
(**clt).status()==HardBranching::Incoming) {
continue;
}
// both outgoing
else if((**cjt).status()!=HardBranching::Incoming&&
branch->status()==HardBranching::Outgoing) {
Boost boost=((*cjt)->pVector()+branch->pVector()).findBoostToCM();
Lorentz5Momentum pcm = branch->pVector();
pcm.boost(boost);
Lorentz5Momentum nvect = Lorentz5Momentum(ZERO,pcm.vect());
nvect.boost( -boost);
(**cjt).nVector(nvect);
}
else if((**cjt).status()==HardBranching::Incoming) {
Lorentz5Momentum pa = -(**cjt).showerMomentum()+branch->showerMomentum();
Lorentz5Momentum pb = (**cjt).showerMomentum();
Axis axis(pa.vect().unit());
LorentzRotation rot;
double sinth(sqrt(sqr(axis.x())+sqr(axis.y())));
rot.setRotate(-acos(axis.z()),Axis(-axis.y()/sinth,axis.x()/sinth,0.));
rot.rotateX(Constants::pi);
rot.boostZ( pa.e()/pa.vect().mag());
pb*=rot;
Boost trans = -1./pb.e()*pb.vect();
trans.setZ(0.);
rot.boost(trans);
Energy scale=(**cjt).beam()->momentum().e();
Lorentz5Momentum pbasis(ZERO,(**cjt).beam()->momentum().vect().unit()*scale);
Lorentz5Momentum pcm = rot*pbasis;
rot.invert();
(**cjt).nVector(rot*Lorentz5Momentum(ZERO,-pcm.vect()));
tHardBranchingPtr branch2 = *cjt;;
while (branch2->parent()) {
branch2=branch2->parent();
branch2->nVector(rot*Lorentz5Momentum(ZERO,-pcm.vect()));
}
}
else if(branch->status()==HardBranching::Incoming) {
(**cjt).nVector(Lorentz5Momentum(ZERO,branch->showerMomentum().vect()));
}
}
// now compute the new momenta
for(cjt=tree->branchings().begin();cjt!=tree->branchings().end();++cjt) {
if(!(*cjt)->branchingParticle()->isFinalState()) continue;
Lorentz5Momentum qnew;
if((*cjt)->branchingParticle()->partner()) {
Energy2 dot=(*cjt)->pVector()*(*cjt)->nVector();
double beta = 0.5*((*cjt)->branchingParticle()->momentum().m2()
-sqr((*cjt)->pVector().mass()))/dot;
qnew=(*cjt)->pVector()+beta*(*cjt)->nVector();
qnew.rescaleMass();
}
else {
qnew = (*cjt)->pVector();
}
// qnew is the unshuffled momentum in the rest frame of the p basis vectors,
// for the simple case Z->q qbar g this was checked against analytic formulae.
// compute the boost
LorentzRotation R=solveBoost(qnew,
toRest*(*cjt)->branchingParticle()->momentum())*toRest;
(*cjt)->setMomenta(R,1.0,Lorentz5Momentum());
}
}
Energy QTildeReconstructor::momConsEq(const double & k,
const Energy & root_s,
const JetKinVect & jets) const {
static const Energy2 eps=1e-8*GeV2;
Energy dum = ZERO;
for(JetKinVect::const_iterator it = jets.begin(); it != jets.end(); ++it) {
Energy2 dum2 = (it->q).m2() + sqr(k)*(it->p).vect().mag2();
if(dum2 < ZERO) {
if(dum2 < -eps) throw KinematicsReconstructionVeto();
dum2 = ZERO;
}
dum += sqrt(dum2);
}
return dum - root_s;
}
void QTildeReconstructor::boostChain(tPPtr p, const LorentzRotation &bv,
tPPtr & parent) const {
if(!p->parents().empty()) boostChain(p->parents()[0], bv,parent);
else parent=p;
p->transform(bv);
if(p->children().size()==2) {
if(dynamic_ptr_cast<ShowerParticlePtr>(p->children()[1]))
deepTransform(p->children()[1],bv);
}
}
namespace {
bool sortJets(ShowerProgenitorPtr j1, ShowerProgenitorPtr j2) {
return j1->highestpT()>j2->highestpT();
}
}
void QTildeReconstructor::
reconstructGeneralSystem(vector<ShowerProgenitorPtr> & ShowerHardJets) const {
static const Energy2 minQ2 = 1e-4*GeV2;
map<ShowerProgenitorPtr,bool> used;
for(unsigned int ix=0;ix<ShowerHardJets.size();++ix) {
used[ShowerHardJets[ix]] = false;
}
if(_reconopt<=2) {
if(_reconopt==2) {
// first to the final-state reconstruction of any systems which need it
set<ShowerProgenitorPtr> outgoing;
// first find any particles with final state partners
for(unsigned int ix=0;ix<ShowerHardJets.size();++ix) {
if(ShowerHardJets[ix]->progenitor()->isFinalState()&&
ShowerHardJets[ix]->progenitor()->partner()&&
ShowerHardJets[ix]->progenitor()->partner()->isFinalState()) outgoing.insert(ShowerHardJets[ix]);
}
// then find the colour partners
if(!outgoing.empty()) {
set<ShowerProgenitorPtr> partners;
for(set<ShowerProgenitorPtr>::const_iterator it=outgoing.begin();it!=outgoing.end();++it) {
for(unsigned int ix=0;ix<ShowerHardJets.size();++ix) {
if((**it).progenitor()->partner()==ShowerHardJets[ix]->progenitor()) {
partners.insert(ShowerHardJets[ix]);
break;
}
}
}
outgoing.insert(partners.begin(),partners.end());
}
// to the final-state reconstruction if needed
if(!outgoing.empty()) {
assert(outgoing.size()!=1);
LorentzRotation toRest,fromRest;
vector<ShowerProgenitorPtr> outgoingJets(outgoing.begin(),outgoing.end());
reconstructFinalStateSystem(false,toRest,fromRest,outgoingJets);
}
// Now do any initial-final systems which are needed
vector<ColourSingletSystem> IFSystems;
// find the systems N.B. can have duplicates
// find initial-state with FS partners or FS with IS partners
for(unsigned int ix=0;ix<ShowerHardJets.size();++ix) {
if(!ShowerHardJets[ix]->progenitor()->isFinalState()&&
ShowerHardJets[ix]->progenitor()->partner()&&
ShowerHardJets[ix]->progenitor()->partner()->isFinalState()) {
IFSystems.push_back(ColourSingletSystem(IF,ShowerHardJets[ix]));
}
else if(ShowerHardJets[ix]->progenitor()->isFinalState()&&
ShowerHardJets[ix]->progenitor()->partner()&&
!ShowerHardJets[ix]->progenitor()->partner()->isFinalState()) {
IFSystems.push_back(ColourSingletSystem(IF,ShowerHardJets[ix]));
}
}
// then add the partners
for(unsigned int is=0;is<IFSystems.size();++is) {
for(unsigned int ix=0;ix<ShowerHardJets.size();++ix) {
if(IFSystems[is].jets[0]->progenitor()->partner()==ShowerHardJets[ix]->progenitor()) {
IFSystems[is].jets.push_back(ShowerHardJets[ix]);
}
}
// ensure incoming first
if(IFSystems[is].jets[0]->progenitor()->isFinalState())
swap(IFSystems[is].jets[0],IFSystems[is].jets[1]);
}
if(!IFSystems.empty()) {
unsigned int istart = UseRandom::irnd(IFSystems.size());
unsigned int istop=IFSystems.size();
for(unsigned int is=istart;is<=istop;++is) {
if(is==IFSystems.size()) {
if(istart!=0) {
istop = istart-1;
is=0;
}
else break;
}
// skip duplicates
if(used[IFSystems[is].jets[0]] &&
used[IFSystems[is].jets[1]] ) continue;
if(IFSystems[is].jets[0]->original()&&IFSystems[is].jets[0]->original()->parents().empty()) continue;
Lorentz5Momentum psum;
for(unsigned int ix=0;ix<IFSystems[is].jets.size();++ix) {
if(IFSystems[is].jets[ix]->progenitor()->isFinalState())
psum += IFSystems[is].jets[ix]->progenitor()->momentum();
else
psum -= IFSystems[is].jets[ix]->progenitor()->momentum();
}
if(-psum.m2()>minQ2) {
reconstructInitialFinalSystem(IFSystems[is].jets);
for(unsigned int ix=0;ix<IFSystems[is].jets.size();++ix) {
used[IFSystems[is].jets[ix]] = true;
}
}
}
}
}
// now we finally need to handle the initial state system
ColourSingletSystem in,out;
for(unsigned int ix=0;ix<ShowerHardJets.size();++ix) {
if(ShowerHardJets[ix]->progenitor()->isFinalState())
out.jets.push_back(ShowerHardJets[ix]);
else
in.jets.push_back(ShowerHardJets[ix]);
}
// reconstruct initial-initial system
bool doRecon = false;
for(unsigned int ix=0;ix<in.jets.size();++ix) {
if(!used[in.jets[ix]]) {
doRecon = true;
break;
}
}
LorentzRotation toRest,fromRest;
bool applyBoost(false);
if(doRecon) {
reconstructInitialInitialSystem(applyBoost,toRest,fromRest,in.jets);
}
// reconstruct the final-state systems
if(!doRecon) {
for(unsigned int ix=0;ix<out.jets.size();++ix) {
if(!used[out.jets[ix]]) {
doRecon = true;
break;
}
}
}
if(doRecon) {
reconstructFinalStateSystem(applyBoost,toRest,fromRest,out.jets);
}
}
else if(_reconopt==3 || _reconopt==4 ) {
// sort the vector by hardness of emission
std::sort(ShowerHardJets.begin(),ShowerHardJets.end(),sortJets);
// map between particles and progenitors for easy lookup
map<ShowerParticlePtr,ShowerProgenitorPtr> progenitorMap;
for(unsigned int ix=0;ix<ShowerHardJets.size();++ix) {
progenitorMap[ShowerHardJets[ix]->progenitor()] = ShowerHardJets[ix];
}
for(unsigned int ix=0;ix<ShowerHardJets.size();++ix) {
// skip jets which have already been handled
if(ShowerHardJets[ix]->reconstructed()==ShowerProgenitor::done) continue;
// already reconstructed
if(used[ShowerHardJets[ix]]) continue;
// no partner continue
if(!ShowerHardJets[ix]->progenitor()->partner()) continue;
// do the reconstruction
// final-final
if(ShowerHardJets[ix]->progenitor()->isFinalState() &&
ShowerHardJets[ix]->progenitor()->partner()->isFinalState() ) {
LorentzRotation toRest,fromRest;
vector<ShowerProgenitorPtr> jets(2);
jets[0] = ShowerHardJets[ix];
jets[1] = progenitorMap[ShowerHardJets[ix]->progenitor()->partner()];
if(_reconopt==4 && jets[1]->reconstructed()==ShowerProgenitor::notReconstructed)
jets[1]->reconstructed(ShowerProgenitor::dontReconstruct);
reconstructFinalStateSystem(false,toRest,fromRest,jets);
if(_reconopt==4 && jets[1]->reconstructed()==ShowerProgenitor::dontReconstruct)
jets[1]->reconstructed(ShowerProgenitor::notReconstructed);
used[jets[0]] = true;
if(_reconopt==3) used[jets[1]] = true;
}
// initial-final
else if((ShowerHardJets[ix]->progenitor()->isFinalState() &&
!ShowerHardJets[ix]->progenitor()->partner()->isFinalState()) ||
(!ShowerHardJets[ix]->progenitor()->isFinalState() &&
ShowerHardJets[ix]->progenitor()->partner()->isFinalState()) ) {
vector<ShowerProgenitorPtr> jets(2);
jets[0] = ShowerHardJets[ix];
jets[1] = progenitorMap[ShowerHardJets[ix]->progenitor()->partner()];
if(jets[0]->progenitor()->isFinalState()) swap(jets[0],jets[1]);
if(jets[0]->original()&&jets[0]->original()->parents().empty()) continue;
Lorentz5Momentum psum;
for(unsigned int iy=0;iy<jets.size();++iy) {
if(jets[iy]->progenitor()->isFinalState())
psum += jets[iy]->progenitor()->momentum();
else
psum -= jets[iy]->progenitor()->momentum();
}
if(-psum.m2()>minQ2) {
if(_reconopt==4 && progenitorMap[ShowerHardJets[ix]->progenitor()->partner()]->reconstructed()==ShowerProgenitor::notReconstructed)
progenitorMap[ShowerHardJets[ix]->progenitor()->partner()]->reconstructed(ShowerProgenitor::dontReconstruct);
reconstructInitialFinalSystem(jets);
if(_reconopt==4 && progenitorMap[ShowerHardJets[ix]->progenitor()->partner()]->reconstructed()==ShowerProgenitor::dontReconstruct)
progenitorMap[ShowerHardJets[ix]->progenitor()->partner()]->reconstructed(ShowerProgenitor::notReconstructed);
used[ShowerHardJets[ix]] = true;
if(_reconopt==3) used[progenitorMap[ShowerHardJets[ix]->progenitor()->partner()]] = true;
}
}
// initial-initial
else if(!ShowerHardJets[ix]->progenitor()->isFinalState() &&
!ShowerHardJets[ix]->progenitor()->partner()->isFinalState() ) {
ColourSingletSystem in,out;
in.jets.push_back(ShowerHardJets[ix]);
in.jets.push_back(progenitorMap[ShowerHardJets[ix]->progenitor()->partner()]);
for(unsigned int iy=0;iy<ShowerHardJets.size();++iy) {
if(ShowerHardJets[iy]->progenitor()->isFinalState())
out.jets.push_back(ShowerHardJets[iy]);
}
LorentzRotation toRest,fromRest;
bool applyBoost(false);
if(_reconopt==4 && in.jets[1]->reconstructed()==ShowerProgenitor::notReconstructed)
in.jets[1]->reconstructed(ShowerProgenitor::dontReconstruct);
reconstructInitialInitialSystem(applyBoost,toRest,fromRest,in.jets);
if(_reconopt==4 && in.jets[1]->reconstructed()==ShowerProgenitor::dontReconstruct)
in.jets[1]->reconstructed(ShowerProgenitor::notReconstructed);
used[in.jets[0]] = true;
if(_reconopt==3) used[in.jets[1]] = true;
for(unsigned int iy=0;iy<out.jets.size();++iy) {
if(out.jets[iy]->reconstructed()==ShowerProgenitor::notReconstructed)
out.jets[iy]->reconstructed(ShowerProgenitor::dontReconstruct);
}
// reconstruct the final-state systems
LorentzRotation finalBoosts;
finalBoosts.transform( toRest);
finalBoosts.transform(fromRest);
for(unsigned int iy=0;iy<out.jets.size();++iy) {
deepTransform(out.jets[iy]->progenitor(),finalBoosts);
}
for(unsigned int iy=0;iy<out.jets.size();++iy) {
if(out.jets[iy]->reconstructed()==ShowerProgenitor::dontReconstruct)
out.jets[iy]->reconstructed(ShowerProgenitor::notReconstructed);
}
}
else {
assert(false);
}
}
}
}
bool QTildeReconstructor::
inverseDecayRescalingFactor(vector<Lorentz5Momentum> pout,
vector<Energy> mon,Energy roots,
Lorentz5Momentum ppartner, Energy mbar,
double & k1, double & k2) const {
ThreeVector<Energy> qtotal;
vector<Energy2> pmag;
for(unsigned int ix=0;ix<pout.size();++ix) {
pmag.push_back(pout[ix].vect().mag2());
qtotal+=pout[ix].vect();
}
Energy2 dot1 = qtotal*ppartner.vect();
Energy2 qmag2=qtotal.mag2();
double a = -dot1/qmag2;
static const Energy eps=1e-10*GeV;
unsigned int itry(0);
Energy numer(ZERO),denom(ZERO);
k1=1.;
do {
++itry;
numer=denom=0.*GeV;
double k12=sqr(k1);
for(unsigned int ix=0;ix<pout.size();++ix) {
Energy en = sqrt(pmag[ix]/k12+sqr(mon[ix]));
numer += en;
denom += pmag[ix]/en;
}
Energy en = sqrt(qmag2/k12+sqr(mbar));
numer += en-roots;
denom += qmag2/en;
k1 += numer/denom*k12*k1;
if(abs(k1)>1e10) return false;
}
while (abs(numer)>eps&&itry<100);
k1 = abs(k1);
k2 = a*k1;
return itry<100;
}
void QTildeReconstructor::
findPartners(HardBranchingPtr branch,set<HardBranchingPtr> & done,
const set<HardBranchingPtr> & branchings,
vector<HardBranchingPtr> & jets) const {
tShowerParticlePtr part=branch->branchingParticle();
unsigned int partNumColourLines =
branch->branchingParticle()->colourInfo()-> colourLines().size();
unsigned int partNumAColourLines =
branch->branchingParticle()->colourInfo()->antiColourLines().size();
for(set<HardBranchingPtr>::const_iterator cit=branchings.begin();
cit!=branchings.end();++cit) {
if(done.find(*cit)!=done.end()||!(**cit).branchingParticle()->coloured())
continue;
bool isPartner = false;
// one initial and one final
if(branch->status()!=(**cit).status()) {
if(part->colourLine()) {
for(unsigned int ix=0; ix<partNumColourLines; ++ix){
for(unsigned int jx=0; jx<CLSIZE(cit); ++jx){
if(part->colourInfo()->colourLines()[ix] ==
(**cit).branchingParticle()->colourInfo()->colourLines()[jx]){
isPartner = true;
break;
}
}
}
}
if(part->antiColourLine()) {
for(unsigned int ix=0; ix<partNumAColourLines; ++ix){
for(unsigned int jx=0; jx<ACLSIZE(cit); ++jx){
if(part->colourInfo()->antiColourLines()[ix] ==
(**cit).branchingParticle()->colourInfo()->antiColourLines()[jx]){
isPartner = true;
break;
}
}
}
}
}
// both in either initial or final state
else {
if(part->colourLine()) {
for(unsigned int ix=0; ix<partNumColourLines; ++ix) {
for(unsigned int jx=0; jx<ACLSIZE(cit); ++jx) {
if(part->colourInfo()->colourLines()[ix] ==
(**cit).branchingParticle()->colourInfo()->antiColourLines()[jx]){
isPartner = true;
break;
}
}
}
}
if(part->antiColourLine()) {
for(unsigned int ix=0; ix<partNumAColourLines; ++ix){
for(unsigned int jx=0; jx<CLSIZE(cit); ++jx){
if(part->colourInfo()->antiColourLines()[ix] ==
(**cit).branchingParticle()->colourInfo()->colourLines()[jx]){
isPartner = true;
break;
}
}
}
}
}
if(isPartner) {
jets.push_back(*cit);
done.insert(*cit);
findPartners(*cit,done,branchings,jets);
}
}
}
void QTildeReconstructor::
deconstructInitialFinalSystem(HardTreePtr tree,vector<HardBranchingPtr> jets,
cEvolverPtr evolver,
ShowerInteraction::Type type) const {
HardBranchingPtr incoming;
Lorentz5Momentum pin[2],pout[2],pbeam;
HardBranchingPtr initial;
Energy mc(ZERO);
for(unsigned int ix=0;ix<jets.size();++ix) {
// final-state parton
if(jets[ix]->status()==HardBranching::Outgoing) {
pout[0] += jets[ix]->branchingParticle()->momentum();
mc = jets[ix]->branchingParticle()->thePEGBase() ?
jets[ix]->branchingParticle()->thePEGBase()->mass() :
jets[ix]->branchingParticle()->dataPtr()->mass();
}
// initial-state parton
else {
pin[0] += jets[ix]->branchingParticle()->momentum();
initial = jets[ix];
pbeam = jets[ix]->beam()->momentum();
Energy scale=pbeam.t();
pbeam = Lorentz5Momentum(ZERO,pbeam.vect().unit()*scale);
incoming = jets[ix];
while(incoming->parent()) incoming = incoming->parent();
}
}
if(jets.size()>2) {
pout[0].rescaleMass();
mc = pout[0].mass();
}
// work out the boost to the Breit frame
Lorentz5Momentum pa = pout[0]-pin[0];
Axis axis(pa.vect().unit());
LorentzRotation rot;
double sinth(sqrt(sqr(axis.x())+sqr(axis.y())));
if(axis.perp2()>0.) {
rot.setRotate(-acos(axis.z()),Axis(-axis.y()/sinth,axis.x()/sinth,0.));
rot.rotateX(Constants::pi);
rot.boostZ( pa.e()/pa.vect().mag());
}
// transverse part
Lorentz5Momentum paxis=rot*pbeam;
Boost trans = -1./paxis.e()*paxis.vect();
trans.setZ(0.);
rot.boost(trans);
pa *= rot;
// reference vectors
Lorentz5Momentum n1(ZERO,ZERO,-pa.z(),-pa.z());
Lorentz5Momentum n2(ZERO,ZERO, pa.z(),-pa.z());
Energy2 n1n2 = n1*n2;
// decompose the momenta
Lorentz5Momentum qbp=rot*pin[0],qcp= rot*pout[0];
double a[2],b[2];
a[0] = n2*qbp/n1n2;
b[0] = n1*qbp/n1n2;
a[1] = n2*qcp/n1n2;
b[1] = n1*qcp/n1n2;
Lorentz5Momentum qperp = qbp-a[0]*n1-b[0]*n2;
// before reshuffling
Energy Q = abs(pa.z());
double c = sqr(mc/Q);
Lorentz5Momentum pb(ZERO,ZERO,0.5*Q*(1.+c),0.5*Q*(1.+c));
Lorentz5Momentum pc(ZERO,ZERO,0.5*Q*(c-1.),0.5*Q*(1.+c));
double anew[2],bnew[2];
anew[0] = pb*n2/n1n2;
bnew[0] = 0.5*(qbp.m2()-qperp.m2())/n1n2/anew[0];
bnew[1] = pc*n1/n1n2;
anew[1] = 0.5*qcp.m2()/bnew[1]/n1n2;
Lorentz5Momentum qnewb = (anew[0]*n1+bnew[0]*n2+qperp);
Lorentz5Momentum qnewc = (anew[1]*n1+bnew[1]*n2);
// initial-state boost
LorentzRotation rotinv=rot.inverse();
LorentzRotation transb=rotinv*solveBoostZ(qnewb,qbp)*rot;
// final-state boost
LorentzRotation transc=rotinv*solveBoost(qnewc,qcp)*rot;
// this will need changing for more than one outgoing particle
// set the pvectors
for(unsigned int ix=0;ix<jets.size();++ix) {
if(jets[ix]->status()==HardBranching::Incoming) {
jets[ix]->pVector(pbeam);
jets[ix]->showerMomentum(rotinv*pb);
incoming->pVector(jets[ix]->pVector());
}
else {
jets[ix]->pVector(rotinv*pc);
jets[ix]->showerMomentum(jets[ix]->pVector());
}
}
// find the colour partners
ShowerParticleVector particles;
vector<Lorentz5Momentum> ptemp;
set<HardBranchingPtr>::const_iterator cjt;
for(cjt=tree->branchings().begin();cjt!=tree->branchings().end();++cjt) {
ptemp.push_back((**cjt).branchingParticle()->momentum());
(**cjt).branchingParticle()->set5Momentum((**cjt).showerMomentum());
particles.push_back((**cjt).branchingParticle());
}
evolver->showerModel()->partnerFinder()
->setInitialEvolutionScales(particles,false,type,false);
unsigned int iloc(0);
for(cjt=tree->branchings().begin();cjt!=tree->branchings().end();++cjt) {
// reset the momentum
(**cjt).branchingParticle()->set5Momentum(ptemp[iloc]);
++iloc;
}
for(vector<HardBranchingPtr>::const_iterator cjt=jets.begin();
cjt!=jets.end();++cjt) {
// sort out the partners
tShowerParticlePtr partner =
(*cjt)->branchingParticle()->partner();
if(!partner) continue;
tHardBranchingPtr branch;
for(set<HardBranchingPtr>::const_iterator
clt=tree->branchings().begin();clt!=tree->branchings().end();++clt) {
if((**clt).branchingParticle()==partner) {
(**cjt).colourPartner(*clt);
branch=*clt;
break;
}
}
// compute the reference vectors
// both incoming, should all ready be done
if((**cjt).status()==HardBranching::Incoming &&
branch->status()==HardBranching::Incoming) {
Energy etemp = (*cjt)->beam()->momentum().z();
Lorentz5Momentum nvect(ZERO, ZERO,-etemp, abs(etemp));
tHardBranchingPtr branch2 = *cjt;
(**cjt).nVector(nvect);
while (branch2->parent()) {
branch2=branch2->parent();
branch2->nVector(nvect);
}
}
// both outgoing
else if((**cjt).status()==HardBranching::Outgoing&&
branch->status()==HardBranching::Outgoing) {
Boost boost=((*cjt)->pVector()+branch->pVector()).findBoostToCM();
Lorentz5Momentum pcm = branch->pVector();
pcm.boost(boost);
Lorentz5Momentum nvect = Lorentz5Momentum(ZERO,pcm.vect());
nvect.boost( -boost);
(**cjt).nVector(nvect);
}
else if((**cjt).status()==HardBranching::Incoming) {
Lorentz5Momentum pa = -(**cjt).showerMomentum()+branch->showerMomentum();
Lorentz5Momentum pb = (**cjt).showerMomentum();
Axis axis(pa.vect().unit());
LorentzRotation rot;
double sinth(sqrt(sqr(axis.x())+sqr(axis.y())));
if(axis.perp2()>1e-20) {
rot.setRotate(-acos(axis.z()),Axis(-axis.y()/sinth,axis.x()/sinth,0.));
rot.rotateX(Constants::pi);
}
if(abs(1.-pa.e()/pa.vect().mag())>1e-6) rot.boostZ( pa.e()/pa.vect().mag());
pb*=rot;
Boost trans = -1./pb.e()*pb.vect();
trans.setZ(0.);
rot.boost(trans);
Energy scale=(**cjt).beam()->momentum().t();
Lorentz5Momentum pbasis(ZERO,(**cjt).beam()->momentum().vect().unit()*scale);
Lorentz5Momentum pcm = rot*pbasis;
rot.invert();
Lorentz5Momentum nvect = rot*Lorentz5Momentum(ZERO,-pcm.vect());
(**cjt).nVector(nvect);
tHardBranchingPtr branch2 = *cjt;
while (branch2->parent()) {
branch2=branch2->parent();
branch2->nVector(nvect);
}
}
else if(branch->status()==HardBranching::Incoming) {
Lorentz5Momentum nvect=Lorentz5Momentum(ZERO,branch->showerMomentum().vect());
(**cjt).nVector(nvect);
}
}
// now compute the new momenta
for(vector<HardBranchingPtr>::const_iterator cjt=jets.begin();
cjt!=jets.end();++cjt) {
if((**cjt).status()==HardBranching::Outgoing) {
(**cjt).setMomenta(transc,1.,Lorentz5Momentum());
}
}
incoming->setMomenta(transb,1.,Lorentz5Momentum());
}
void QTildeReconstructor::deepTransform(PPtr particle,
const LorentzRotation & r,
bool match,
PPtr original) const {
if(_boosts.find(particle)!=_boosts.end()) {
_boosts[particle] *= r;
}
Lorentz5Momentum porig = particle->momentum();
if(!original) original = particle;
for ( int i = 0, N = particle->children().size(); i < N; ++i ) {
deepTransform(particle->children()[i],r,
particle->children()[i]->id()==original->id()&&match,original);
}
particle->transform(r);
// transform the p and n vectors
ShowerParticlePtr sparticle = dynamic_ptr_cast<ShowerParticlePtr>(particle);
if(sparticle && sparticle->showerKinematics()) {
sparticle->showerKinematics()->transform(r);
}
if ( particle->next() ) deepTransform(particle->next(),r,match,original);
if(!match) return;
if(!particle->children().empty()) return;
+ // force the mass shell
+ Lorentz5Momentum ptemp = particle->momentum();
+ ptemp.rescaleEnergy();
+ particle->set5Momentum(ptemp);
// check if there's a daughter tree which also needs boosting
map<tShowerTreePtr,pair<tShowerProgenitorPtr,tShowerParticlePtr> >::const_iterator tit;
for(tit = _currentTree->treelinks().begin();
tit != _currentTree->treelinks().end();++tit) {
// if there is, boost it
if(tit->second.first && tit->second.second==original) {
Lorentz5Momentum pnew = tit->first->incomingLines().begin()
->first->progenitor()->momentum();
pnew *= tit->first->transform();
Lorentz5Momentum pdiff = porig-pnew;
Energy2 test = sqr(pdiff.x()) + sqr(pdiff.y()) +
sqr(pdiff.z()) + sqr(pdiff.t());
LorentzRotation rot;
if(test>1e-6*GeV2) rot = solveBoost(porig,pnew);
tit->first->transform(r*rot,false);
}
}
}
void QTildeReconstructor::reconstructFinalFinalOffShell(JetKinVect orderedJets,
Energy2 s,
bool recursive) const {
JetKinVect::iterator jit;
jit = orderedJets.begin(); ++jit;
// 4-momentum of recoiling system
Lorentz5Momentum psum;
for( ; jit!=orderedJets.end(); ++jit) psum += jit->p;
psum.rescaleMass();
// calculate the 3-momentum rescaling factor
Energy2 m1sq(orderedJets.begin()->q.m2()),m2sq(psum.m2());
Energy4 num = sqr(s - m1sq - m2sq) - 4.*m1sq*m2sq;
if(num<ZERO) throw KinematicsReconstructionVeto();
double k = sqrt( num / (4.*s*orderedJets.begin()->p.vect().mag2()) );
// boost the most off-shell
LorentzRotation B1 = solveBoost(k, orderedJets.begin()->q, orderedJets.begin()->p);
deepTransform(orderedJets.begin()->parent,B1);
// boost everything else
// first to rescale
LorentzRotation B2 = solveBoost(k, psum, psum);
// and then to rest frame of new system
Lorentz5Momentum pnew = B2*psum;
pnew.rescaleMass();
B2.transform(pnew.findBoostToCM());
// apply transform (calling routine ensures at least 3 elements)
jit = orderedJets.begin(); ++jit;
for(;jit!=orderedJets.end();++jit) {
deepTransform(jit->parent,B2);
jit->p *= B2;
jit->q *= B2;
}
JetKinVect newJets(orderedJets.begin()+1,orderedJets.end());
// final reconstruction
if(newJets.size()==2 || !recursive ) {
// rescaling factor
double k = solveKfactor(psum.m(), newJets);
// rescale jets in the new CMF
for(JetKinVect::iterator it = newJets.begin(); it != newJets.end(); ++it) {
LorentzRotation Trafo = solveBoost(k, it->q, it->p);
deepTransform(it->parent,Trafo);
}
}
// recursive
else {
std::sort(newJets.begin(),newJets.end(),JetOrdering());
reconstructFinalFinalOffShell(newJets,psum.m2(),recursive);
}
// finally boost back from new CMF
LorentzRotation back(-pnew.findBoostToCM());
for(JetKinVect::iterator it = newJets.begin(); it != newJets.end(); ++it) {
deepTransform(it->parent,back);
}
}
Energy QTildeReconstructor::findMass(HardBranchingPtr branch) const {
// KH - 230909 - If the particle has no children then it will
// not have showered and so it should be "on-shell" so we can
// get it's mass from it's momentum. This means that the
// inverseRescalingFactor doesn't give any nans or do things
// it shouldn't if it gets e.g. two Z bosons generated with
// off-shell masses. This is for sure not the best solution.
// PR 1/1/10 modification to previous soln
// PR 28/8/14 change to procedure and factorize into a function
if(branch->children().empty()) {
return branch->branchingParticle()->mass();
}
else if(!branch->children().empty() &&
!branch->branchingParticle()->dataPtr()->stable() ) {
for(unsigned int ix=0;ix<branch->children().size();++ix) {
if(branch->branchingParticle()->id()==
branch->children()[ix]->branchingParticle()->id())
return findMass(branch->children()[ix]);
}
}
return branch->branchingParticle()->dataPtr()->mass();
}
vector<double>
QTildeReconstructor::initialStateRescaling(double x1, double x2, Energy MDY,
vector<Lorentz5Momentum> & p,
vector<Lorentz5Momentum> & pq,
const vector<Energy>& highestpts) const {
Energy2 S = (pq[0]+pq[1]).m2();
// find alphas and betas in terms of desired basis
Energy2 p12 = pq[0]*pq[1];
double a[2] = {p[0]*pq[1]/p12,p[1]*pq[1]/p12};
double b[2] = {p[0]*pq[0]/p12,p[1]*pq[0]/p12};
Lorentz5Momentum p1p = p[0] - a[0]*pq[0] - b[0]*pq[1];
Lorentz5Momentum p2p = p[1] - a[1]*pq[0] - b[1]*pq[1];
// compute kappa
// we always want to preserve the mass of the system
Energy2 A = a[0]*b[1]*S;
Energy2 B = Energy2(sqr(MDY)) - (a[0]*b[0]+a[1]*b[1])*S - (p1p+p2p).m2();
Energy2 C = a[1]*b[0]*S;
double rad = 1.-4.*A*C/sqr(B);
if(rad < 0.) throw KinematicsReconstructionVeto();
double kp = B/(2.*A)*(1.+sqrt(rad));
// now compute k1
// conserve rapidity
double k1(0.);
double k2(0.);
if(_initialStateReconOption==0) {
rad = kp*(b[0]+kp*b[1])/(kp*a[0]+a[1])*(x1/x2);
if(rad <= 0.) throw KinematicsReconstructionVeto();
k1 = sqrt(rad);
k2 = kp/k1;
}
// conserve longitudinal momentum
else if(_initialStateReconOption==1) {
double a2 = (a[0]+a[1]/kp);
double b2 = -x2+x1;
double c2 = -(b[1]*kp+b[0]);
if(abs(b2)>1e-10) {
double discrim = 1.-4.*a2*c2/sqr(b2);
if(discrim < 0.) throw KinematicsReconstructionVeto();
k1 = b2>0. ? 0.5*b2/a2*(1.+sqrt(discrim)) : 0.5*b2/a2*(1.-sqrt(discrim));
}
else {
k1 = -c2/a2;
if( k1 <= 0.) throw KinematicsReconstructionVeto();
k1 = sqrt(k1);
}
k2 = kp/k1;
}
// preserve mass and don't scale the softer system
// to reproduce the dipole kinematics
else if(_initialStateReconOption==2) {
// in this case kp = k1 or k2 depending on who's the harder guy
k1 = kp; k2 = 1.;
if ( highestpts[0] < highestpts[1] )
swap(k1,k2);
}
else
assert(false);
// calculate the boosts
vector<double> beta(2);
beta[0] = getBeta((a[0]+b[0]), (a[0]-b[0]), (k1*a[0]+b[0]/k1), (k1*a[0]-b[0]/k1));
beta[1] = getBeta((a[1]+b[1]), (a[1]-b[1]), (a[1]/k2+k2*b[1]), (a[1]/k2-k2*b[1]));
if (pq[0].z() > ZERO) {
beta[0] = -beta[0];
beta[1] = -beta[1];
}
return beta;
}

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