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HardTree.cc
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// -*- C++ -*-
//
// This is the implementation of the non-inlined, non-templated member
// functions of the HardTree class.
//
#include "HardTree.h"
#include "ThePEG/PDT/EnumParticles.h"
#include "ThePEG/Repository/CurrentGenerator.h"
using namespace Herwig;
HardTree::HardTree(vector<HardBranchingPtr> branchings,
vector<HardBranchingPtr> spacelike,
ShowerInteraction::Type type)
: _interaction(type),
_branchings(branchings.begin(),branchings.end()),
_spacelike (spacelike .begin(),spacelike .end())
{}
bool HardTree::findNodes() {
//clear all containers to be filled
_theExternals.clear();
_theNodes.clear();
_theInternals.clear();
_lowestPt = HardBranchingPtr();
//fix forward relations based on backChild relations
//(these are correctly set during clustering)
fixFwdBranchings();
//find all branchings that initiate a timelike shower
//also add nodes, externals and intermediates from the spacelike line
set< HardBranchingPtr > FS_initiators;
for( set<HardBranchingPtr>::const_iterator it = this->branchings().begin();
it != this->branchings().end(); ++it) {
if( ! (*it)->branchingParticle()->coloured() ) continue;
if( (*it)->status() ==HardBranching::Outgoing ){
//remove any parent ptr that might be set
(*it)->parent( HardBranchingPtr() );
FS_initiators.insert( *it );
continue;
}
HardBranchingPtr spacelike = *it;
while( spacelike->parent() ) {
assert( spacelike == spacelike->parent()->children()[0] );
spacelike = spacelike->parent();
if( ! _lowestPt || _lowestPt->children()[0]->pT()
> spacelike->children()[0]->pT() )
_lowestPt = spacelike;
_theIntermediates.insert( make_pair( spacelike,
spacelike->children()[0] ) );
//nb for bkwd branchings the child contains the splitting variables
_theNodes.insert( make_pair( spacelike->children()[0], spacelike->children()[0]->scale() ) );
FS_initiators.insert( spacelike->children()[0] );
}
_theExternals.insert( make_pair( (*it)->branchingParticle(), *it ) );
}
//fix timelike parent relations once and for all
//fill timelike shower externals nodes and intermediates
for( set<HardBranchingPtr>::const_iterator it = FS_initiators.begin();
it != FS_initiators.end(); ++it){
fixParents( *it );
fillNodes( *it );
}
return true;
}
bool HardTree::fillNodes( HardBranchingPtr branch ){
if( ! branch->children().empty() ) {
if( ! _lowestPt || _lowestPt->children()[0]->pT() > branch->children()[0]->pT() )
_lowestPt = branch;
_theIntermediates.insert( make_pair( branch, branch->children()[0] ) );
_theNodes.insert( make_pair( branch, branch->scale() ) );
fillNodes( branch->children()[0] );
fillNodes( branch->children()[1] );
}
else
_theExternals.insert( make_pair( branch->branchingParticle(), branch ) );
return true;
}
bool HardTree::connect(ShowerTreePtr shower) {
_particles.clear();
// extract the progenitors from the ShowerTree
vector<ShowerProgenitorPtr> progenitors = shower->extractProgenitors();
// connect the trees up
for( set<HardBranchingPtr>::iterator it = branchings().begin();
it != branchings().end(); ++it) {
Energy2 dmin( 1e30*GeV2 );
tShowerParticlePtr partner;
for(unsigned int ix=0;ix<progenitors.size();++ix) {
if((**it).branchingParticle()->id()!=progenitors[ix]->progenitor()->id()) continue;
if(((**it).status()==HardBranching::Incoming&&
progenitors[ix]->progenitor()->isFinalState())||
((**it).status()==HardBranching::Outgoing&&
!progenitors[ix]->progenitor()->isFinalState())) continue;
Energy2 dtest =
sqr( progenitors[ix]->progenitor()->momentum().x() - (**it).showerMomentum().x() ) +
sqr( progenitors[ix]->progenitor()->momentum().y() - (**it).showerMomentum().y() ) +
sqr( progenitors[ix]->progenitor()->momentum().z() - (**it).showerMomentum().z() ) +
sqr( progenitors[ix]->progenitor()->momentum().t() - (**it).showerMomentum().t() );
if( dtest < dmin ) {
partner = progenitors[ix]->progenitor();
dmin = dtest;
}
}
if(!partner) return false;
connect(partner,*it);
if((**it).status()==HardBranching::Incoming) {
double z((**it).z());
tHardBranchingPtr parent=(**it).parent();
while (parent) {
z *= parent->z();
parent = parent->parent();
}
partner->x(z);
}
}
if( particles().size() == progenitors.size() ) return true;
else{
cerr<<"hardTree connect:: size of particles and progenitors does not match \n";
return false;
}
}
ostream & Herwig::operator<<(ostream & os, const HardTree & x) {
os << "Output of HardTree " << &x << "\n";
for(set<HardBranchingPtr>::const_iterator it=x._branchings.begin();
it!=x._branchings.end();++it) {
os << "Hard Particle: " << *(**it).branchingParticle() << " has Sudakov "
<< (**it).sudakov() << "\n";
os << "It's colour lines are " << (**it).branchingParticle()->colourLine() << "\t"
<< (**it).branchingParticle()->antiColourLine() << "\n";
for(unsigned int iy=0;iy<(**it).children().size();++iy) {
os << "\t Children : " << *(**it).children()[iy]->branchingParticle()
<< "\n";
os << "It's colour lines are "
<< (**it).children()[iy]->branchingParticle()->colourLine() << "\t"
<< (**it).children()[iy]->branchingParticle()->antiColourLine() << "\n";
}
}
for(set<HardBranchingPtr>::const_iterator it=x._spacelike.begin();
it!=x._spacelike.end();++it) {
os << "SpaceLike: " << *(**it).branchingParticle() << " has Sudakov"
<< (**it).sudakov() << "\n";
os << "It's colour lines are "
<< (**it).branchingParticle()->colourLine() << "\t"
<< (**it).branchingParticle()->antiColourLine() << "\n";
for(unsigned int iy=0;iy<(**it).children().size();++iy) {
os << "\t Children: " << *(**it).children()[iy]->branchingParticle()
<< "\n";
os << "It's colour lines are "
<< (**it).children()[iy]->branchingParticle()->colourLine() << "\t"
<< (**it).children()[iy]->branchingParticle()->antiColourLine() << "\n";
}
}
return os;
}
void HardTree::fillHardScales( HardBranchingPtr branch, vector< pair< Energy, double > > & currentLine ){
if( branch->children().empty() ) return;
else{
//child[0] continues currentline child[1] creates a new line
//copy contents of old line into newline
vector< pair< Energy, double > > newHardLine = currentLine;
currentLine.push_back( make_pair( branch->scale(),
branch->children()[0]->z() ) );
fillHardScales( branch->children()[0], currentLine );
newHardLine.push_back( make_pair( branch->scale(),
branch->children()[1]->z() ) );
fillHardScales( branch->children()[1], newHardLine );
_hard_line_scales.push_back( newHardLine );
}
}
//this fn needs to be adapted for IS lines
bool HardTree::checkHardOrdering( ) {
//this function also caculates sum of pts of all branchings
_total_pt = 0. * GeV;
_hard_line_scales.clear();
//create timelike proto lines from the outgoing and hardbranchings (the ones in hard process)
vector< pair< HardBranchingPtr, vector< pair< Energy, double > > > > proto_lines;
for( set<HardBranchingPtr>::const_iterator it = this->branchings().begin();
it != this->branchings().end(); ++it) {
if( ! (*it)->branchingParticle()->coloured() ) continue;
if( ! (*it)->status()==HardBranching::Incoming && ! (*it)->children().empty() ) {
vector< pair< Energy, double > > new_hard_line1;
new_hard_line1.push_back( make_pair( (*it)->scale(), (*it)->children()[0]->z() ) );
vector< pair< Energy, double > > new_hard_line2;
new_hard_line2.push_back( make_pair( (*it)->scale(), (*it)->children()[1]->z() ) );
proto_lines.push_back( make_pair( (*it)->children()[0], new_hard_line1 ) );
proto_lines.push_back( make_pair( (*it)->children()[1], new_hard_line2 ) );
//pts of children are equal so just add once
_total_pt += (*it)->children()[0]->pT();
}
else if( (*it)->parent() ) {
//trace all spacelike branchings back following parents
HardBranchingPtr spacelike = *it;
vector< pair< Energy, double > > space_like_line;
while( spacelike->parent() ) {
_total_pt += spacelike->pT();
//create a protoline from the time like child of parent
vector< pair< Energy, double > > time_like_line = space_like_line;
if( spacelike->parent()->children().empty() )
cerr<<"HardTree::checkHardOrdering() connection problem\n";
//timelike child is always first child
time_like_line.push_back( make_pair( spacelike->parent()->scale(),
spacelike->parent()->children()[1]->z() ) );
proto_lines.push_back( make_pair( spacelike->parent()->children()[1], time_like_line ) );
//add the parent to the space_like_line
space_like_line.push_back( make_pair( spacelike->parent()->scale(), 1. ) );
spacelike = spacelike->parent();
}
_hard_line_scales.push_back( space_like_line );
}
}
//recursively fill all timelike lines from proto_lines
for( unsigned int ix = 0; ix < proto_lines.size(); ix++ ) {
fillHardScales( proto_lines[ix].first, proto_lines[ix].second );
_hard_line_scales.push_back( proto_lines[ix].second );
}
//go down each line (outwards from hard sub process) checking angular ordering condition
for( unsigned int ix = 0; ix < _hard_line_scales.size(); ix++ ){
for( unsigned int jx = 0; jx < _hard_line_scales[ix].size(); jx++ ){
if( jx == 0 )
continue;
//angular ordering condition: z_1*q_1 > q2
//this should also work for spacelike lines since for those z was set to 1
if( _hard_line_scales[ix][jx].first > _hard_line_scales[ix][jx - 1].first * _hard_line_scales[ix][ jx - 1 ].second )
return false;
}
}
return true;
}
Energy HardTree::lowestPt( int jetMeasureMode, Energy2 s ){
//check to see we found the _lowest pt correctly
if( !_lowestPt ) {
cerr<<"null lowestpt from tree:\n";
return 0.*GeV;
}
if( _lowestPt->children().size() != 2 ) {
cerr<< "HardTree: wrong no. children = " << _lowestPt->children().size() << " \n";
return 0.*GeV;
}
if( ! _lowestPt->children()[0] ) {
cerr<< "HardTree: null child \n";
return 0.*GeV;
}
Energy kt_softest = _lowestPt->children()[0]->pT();
if( jetMeasureMode != 1 ){
Energy pt = kt_softest;
double z = _lowestPt->children()[0]->z();
Energy2 m0 = sqr( _lowestPt->branchingParticle()->nominalMass() );
Energy2 m1 = sqr( _lowestPt->children()[0]->branchingParticle()->nominalMass() );
Energy2 m2 = sqr( _lowestPt->children()[1]->branchingParticle()->nominalMass() );
double lambda = sqrt( 1. - 4.*m0/s );
double beta1 = 2.*( m1 - sqr(z)*m0 + sqr(pt) )
/ z / lambda / ( lambda + 1. ) / s;
double beta2 = 2.*( m2 - sqr( 1. - z )*m0 + sqr(pt) )
/ ( 1. - z ) / lambda / ( lambda + 1. ) / s;
Energy E1 = sqrt(s)/2.*( z + lambda*beta1 );
Energy E2 = sqrt(s)/2.*( (1.-z) + lambda*beta2 );
Energy Z1 = sqrt(s)/2.*lambda*( z - beta1 );
Energy Z2 = sqrt(s)/2.*lambda*( (1.-z) - beta2 );
double costheta = ( Z1*Z2 - sqr(pt) )
/ sqrt( sqr(Z1)+sqr(pt) ) / sqrt( sqr(Z2)+sqr(pt) );
Energy2 kt_measure;
if( jetMeasureMode == 0 )
kt_measure = 2.*min( sqr(E1), sqr(E2) )*( 1. - costheta );
else if( jetMeasureMode == 2 )
kt_measure = 2.*sqr(E1)*sqr(E2)/sqr(E1+E2)*( 1. - costheta );
kt_softest = sqrt( kt_measure );
}
return kt_softest;
}
bool HardTree::fixFwdBranchings(){
//loop over the spacelike hardbranchings in hard process
set< HardBranchingPtr >::iterator it;
for( it = _branchings.begin(); it != _branchings.end(); ++it ){
HardBranchingPtr current = *it;
if( current->status() ==HardBranching::Outgoing ) continue;
if( !current->branchingParticle()->coloured() ) continue;
current->clearChildren();
current->sudakov( SudakovPtr() );
if( current->backChildren().empty() ) continue;
vector< HardBranchingPtr > backChildren = current->backChildren();
while( ! backChildren.empty() ){
if( backChildren.size() != 2 ) {
cerr << "fixFwdBranchings:: wrong number of back childrem\n";
continue;
}
if( !backChildren[0] || !backChildren[1] ) continue;
//remove any exiting children
backChildren[0]->clearChildren();
backChildren[0]->addChild( current );
backChildren[0]->addChild( backChildren[1] );
current->parent( backChildren[0] );
backChildren[1]->parent ( backChildren[0] );
if( !current->backSudakov() ){
cerr<<"fixFwdBranchings: problem finding backSudakov \n";
continue;
}
backChildren[0]->sudakov( current->backSudakov() );
//continue along incoming line (always the first child)
current = backChildren[0];
backChildren = backChildren[0]->backChildren();
}
}
return true;
}
bool HardTree::fixParents( HardBranchingPtr branch ){
if( branch->children().empty() ) return true;
branch->children()[0]->parent( branch );
fixParents( branch->children()[0] );
branch->children()[1]->parent( branch );
fixParents( branch->children()[1] );
return true;
}

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