EvtBtoXsgamma.cpp

Go to the documentation of this file.

 
/***********************************************************************
* Copyright 1998-2020 CERN for the benefit of the EvtGen authors       *
*                                                                      *
* This file is part of EvtGen.                                         *
*                                                                      *
* EvtGen is free software: you can redistribute it and/or modify       *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation, either version 3 of the License, or    *
* (at your option) any later version.                                  *
*                                                                      *
* EvtGen is distributed in the hope that it will be useful,            *
* but WITHOUT ANY WARRANTY; without even the implied warranty of       *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the        *
* GNU General Public License for more details.                         *
*                                                                      *
* You should have received a copy of the GNU General Public License    *
* along with EvtGen.  If not, see <https://www.gnu.org/licenses/>.     *
***********************************************************************/
 
#include "EvtGenModels/EvtBtoXsgamma.hh"
 
#include "EvtGenBase/EvtConst.hh"
#include "EvtGenBase/EvtGenKine.hh"
#include "EvtGenBase/EvtPDL.hh"
#include "EvtGenBase/EvtParticle.hh"
#include "EvtGenBase/EvtReport.hh"
 
#include "EvtGenModels/EvtBtoXsgammaAliGreub.hh"
#include "EvtGenModels/EvtBtoXsgammaFixedMass.hh"
#include "EvtGenModels/EvtBtoXsgammaFlatEnergy.hh"
#include "EvtGenModels/EvtBtoXsgammaKagan.hh"
 
#include <stdlib.h>
#include <string>
using std::endl;
 
std::string EvtBtoXsgamma::getName() const
{
    return "BTOXSGAMMA";
}
 
EvtDecayBase* EvtBtoXsgamma::clone() const
{
    return new EvtBtoXsgamma;
}
 
void EvtBtoXsgamma::init()
{
    //Arguments:
    // 0: Ali-Greub model = 1, Kagan model = 2
    //No more arguments for Ali-Greub model
    // 1:
    // 2:
    // 3:
 
    // check that at least one b->sg model has been selected
    if ( getNArg() == 0 ) {
        EvtGenReport( EVTGEN_ERROR, "EvtGen" )
            << EvtBtoXsgamma::getName().c_str() << " generator expected "
            << " at least 1 argument but found: " << getNArg() << endl;
        EvtGenReport( EVTGEN_ERROR, "EvtGen" )
            << "Will terminate execution!" << endl;
        ::abort();
    }
 
    // check that there are only two daughters
    checkNDaug( 2 );
 
    // check that second daughter has photon spin
    checkSpinDaughter( 1, EvtSpinType::PHOTON );
}
 
void EvtBtoXsgamma::initProbMax()
{
    noProbMax();
}
 
void EvtBtoXsgamma::decay( EvtParticle* p )
{
    //initialize here. -- its too damn slow otherwise.
 
    if ( m_model == nullptr ) {
        if ( getArg( 0 ) == 1 )
            m_model = std::make_unique<EvtBtoXsgammaAliGreub>();
        else if ( getArg( 0 ) == 2 )
            m_model = std::make_unique<EvtBtoXsgammaKagan>();
        else if ( getArg( 0 ) == 3 )
            m_model = std::make_unique<EvtBtoXsgammaFixedMass>();
        else if ( getArg( 0 ) == 4 )
            m_model = std::make_unique<EvtBtoXsgammaFlatEnergy>();
        else {
            EvtGenReport( EVTGEN_ERROR, "EvtGen" )
                << "No valid EvtBtoXsgamma generator model selected "
                << "Set arg(0) to 1 for Ali-Greub model or 2 for "
                << " Kagan model or 3 for a fixed mass" << endl;
            EvtGenReport( EVTGEN_ERROR, "EvtGen" )
                << "Will terminate execution!" << endl;
            ::abort();
        }
        m_model->init( getNArg(), getArgs() );
    }
 
    //  if ( p->getNDaug() != 0 ) {
    //Will end up here because maxrate multiplies by 1.2
    //  EvtGenReport(EVTGEN_DEBUG,"EvtGen") << "In EvtBtoXsgamma: X_s daughters should not be here!"<<endl;
    //  return;
    //}
 
    double m_b;
    int i;
    p->makeDaughters( getNDaug(), getDaugs() );
    EvtParticle* pdaug[2];
 
    for ( i = 0; i < getNDaug(); i++ ) {
        pdaug[i] = p->getDaug( i );
    }
 
    EvtVector4R p4[2];
    double mass[2];
 
    m_b = p->mass();
 
    mass[1] = EvtPDL::getMass( getDaug( 1 ) );
 
    int Xscode = EvtPDL::getStdHep( getDaug( 0 ) );
 
    mass[0] = m_model->GetMass( Xscode );
 
    EvtGenKine::PhaseSpace( getNDaug(), mass, p4, m_b );
 
    for ( i = 0; i < getNDaug(); i++ ) {
        pdaug[i]->init( getDaugs()[i], p4[i] );
    }
}