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diff --git a/Shower/QTilde/Default/IS_QTildeShowerKinematics1to2.cc b/Shower/QTilde/Default/IS_QTildeShowerKinematics1to2.cc
--- a/Shower/QTilde/Default/IS_QTildeShowerKinematics1to2.cc
+++ b/Shower/QTilde/Default/IS_QTildeShowerKinematics1to2.cc
@@ -1,150 +1,150 @@
// -*- 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/QTilde/Base/ShowerParticle.h"
#include "ThePEG/Utilities/Debug.h"
#include "Herwig/Shower/QTilde/QTildeShowerHandler.h"
#include "Herwig/Shower/QTilde/Base/PartnerFinder.h"
#include "Herwig/Shower/QTilde/Base/ShowerModel.h"
#include "Herwig/Shower/QTilde/Base/KinematicsReconstructor.h"
#include "Herwig/Shower/QTilde/Base/ShowerVertex.h"
#include <cassert>
using namespace Herwig;
void IS_QTildeShowerKinematics1to2::
updateChildren( const tShowerParticlePtr theParent,
const ShowerParticleVector & children,
ShowerPartnerType::Type,
- bool ) const {
+ bool massVeto) const {
const ShowerParticle::Parameters & parent = theParent->showerParameters();
ShowerParticle::Parameters & child0 = children[0]->showerParameters();
ShowerParticle::Parameters & child1 = children[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;
if(massVeto) {
Energy2 q2 = (1.-z())*sqr(scale());
children[1]->scales().Max_Q2 = (1.-z())*q2/z();
}
}
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();
parent ->showerBasis(children[0]->showerBasis(),true);
children[1]->showerBasis(children[0]->showerBasis(),true);
parent ->setShowerMomentum(false);
children[1]->setShowerMomentum(true);
if(! dynamic_ptr_cast<tcQTildeShowerHandlerPtr>(ShowerHandler::currentHandler())->correlations()) return;
SpinPtr pspin(children[0]->spinInfo());
if(!pspin || !dynamic_ptr_cast<tcQTildeShowerHandlerPtr>(ShowerHandler::currentHandler())->spinCorrelations() ) return;
// compute the matrix element for spin correlations
IdList ids;
ids.push_back(parent->dataPtr());
ids.push_back(children[0]->dataPtr());
ids.push_back(children[1]->dataPtr());
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(),false));
// set the incoming particle for the vertex
// (in reality the first child as going backwards)
pspin->decayVertex(vertex);
// construct the spin infos
parent ->constructSpinInfo(false);
children[1]->constructSpinInfo(true);
// connect the spinInfo objects to the vertex
parent ->spinInfo()->productionVertex(vertex);
children[1]->spinInfo()->productionVertex(vertex);
}
void IS_QTildeShowerKinematics1to2::
reconstructParent(const tShowerParticlePtr parent,
const ParticleVector & children ) const {
PPtr c1 = children[0];
ShowerParticlePtr c2 = dynamic_ptr_cast<ShowerParticlePtr>(children[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 * parent->showerBasis()->p_dot_n() );
Lorentz5Momentum pnew = parent->showerBasis()->
sudakov2Momentum(c2param.alpha, c2param.beta,
c2param.ptx , c2param.pty);
pnew.setMass(c2->data().constituentMass());
pnew.rescaleEnergy();
c2->set5Momentum( pnew );
// spacelike child
Lorentz5Momentum pc1(parent->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();
Lorentz5Momentum pVector = theLast->showerBasis()->pVector();
Energy2 pt2 = sqr(px) + sqr(py);
last.alpha = theLast->x();
last.beta = 0.5 * pt2 / last.alpha / theLast->showerBasis()->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);
}

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