EvtSTS.cpp

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* Copyright 1998-2020 CERN for the benefit of the EvtGen authors       *
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#include "EvtGenModels/EvtSTS.hh"
 
#include "EvtGenBase/EvtGenKine.hh"
#include "EvtGenBase/EvtId.hh"
#include "EvtGenBase/EvtPDL.hh"
#include "EvtGenBase/EvtParticle.hh"
#include "EvtGenBase/EvtReport.hh"
#include "EvtGenBase/EvtTensor4C.hh"
#include "EvtGenBase/EvtVector4C.hh"
 
#include <stdlib.h>
#include <string>
 
std::string EvtSTS::getName() const
{
    return "STS";
}
 
EvtDecayBase* EvtSTS::clone() const
{
    return new EvtSTS;
}
 
void EvtSTS::initProbMax()
{
    setProbMax( 20.0 );
}
 
void EvtSTS::init()
{
    // check that there are 0 arguments
    checkNArg( 0 );
    checkNDaug( 2 );
 
    checkSpinParent( EvtSpinType::SCALAR );
 
    checkSpinDaughter( 0, EvtSpinType::TENSOR );
    checkSpinDaughter( 1, EvtSpinType::SCALAR );
}
 
void EvtSTS::decay( EvtParticle* p )
{
    p->initializePhaseSpace( getNDaug(), getDaugs() );
 
    EvtParticle* t1 = p->getDaug( 0 );
 
    EvtVector4R momt = t1->getP4();
    EvtVector4R moms = p->getDaug( 1 )->getP4();
    double masst = t1->mass();
 
    EvtVector4R p4_parent = momt + moms;
 
    double norm = masst * masst /
                  ( p4_parent.mass() * momt.d3mag() * momt.d3mag() );
 
    vertex( 0, norm * t1->epsTensorParent( 0 ).cont1( p4_parent ) * p4_parent );
    vertex( 1, norm * t1->epsTensorParent( 1 ).cont1( p4_parent ) * p4_parent );
    vertex( 2, norm * t1->epsTensorParent( 2 ).cont1( p4_parent ) * p4_parent );
    vertex( 3, norm * t1->epsTensorParent( 3 ).cont1( p4_parent ) * p4_parent );
    vertex( 4, norm * t1->epsTensorParent( 4 ).cont1( p4_parent ) * p4_parent );
 
    return;
}