EvtSVSCP.cpp

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#include "EvtGenModels/EvtSVSCP.hh"

#include "EvtGenBase/EvtCPUtil.hh"
#include "EvtGenBase/EvtConst.hh"
#include "EvtGenBase/EvtGenKine.hh"
#include "EvtGenBase/EvtPDL.hh"
#include "EvtGenBase/EvtParticle.hh"
#include "EvtGenBase/EvtPatches.hh"
#include "EvtGenBase/EvtReport.hh"
#include "EvtGenBase/EvtVector4C.hh"

#include <stdlib.h>
#include <string>

std::string EvtSVSCP::getName()
{
    return "SVS_CP";
}

EvtDecayBase* EvtSVSCP::clone()
{
    return new EvtSVSCP;
}

void EvtSVSCP::init()
{
    // check that there are 7 arguments
    checkNArg( 7 );
    checkNDaug( 2 );

    checkSpinParent( EvtSpinType::SCALAR );

    checkSpinDaughter( 0, EvtSpinType::VECTOR );
    checkSpinDaughter( 1, EvtSpinType::SCALAR );
}

void EvtSVSCP::initProbMax()
{
    //This is probably not quite right, but it should do as a start...
    //Anders

    setProbMax( 2 * ( getArg( 3 ) * getArg( 3 ) + getArg( 5 ) * getArg( 5 ) ) );
}

void EvtSVSCP::decay( EvtParticle* p )
{
    //added by Lange Jan4,2000
    static EvtId B0 = EvtPDL::getId( "B0" );
    static EvtId B0B = EvtPDL::getId( "anti-B0" );

    EvtParticle* v;
    p->initializePhaseSpace( getNDaug(), getDaugs() );
    v = p->getDaug( 0 );
    EvtVector4R momv = v->getP4();
    EvtVector4R moms = p->getDaug( 1 )->getP4();
    double massv = v->mass();
    double t;
    EvtId other_b;

    EvtCPUtil::getInstance()->OtherB( p, t, other_b, 0.5 );

    EvtComplex amp;

    EvtComplex A, Abar;

    A = EvtComplex( getArg( 3 ) * cos( getArg( 4 ) ),
                    getArg( 3 ) * sin( getArg( 4 ) ) );
    Abar = EvtComplex( getArg( 5 ) * cos( getArg( 6 ) ),
                       getArg( 5 ) * sin( getArg( 6 ) ) );

    if ( other_b == B0B ) {
        amp = A * cos( getArg( 1 ) * t / ( 2 * EvtConst::c ) ) +
              EvtComplex( cos( -2.0 * getArg( 0 ) ), sin( -2.0 * getArg( 0 ) ) ) *
                  getArg( 2 ) * EvtComplex( 0.0, 1.0 ) * Abar *
                  sin( getArg( 1 ) * t / ( 2 * EvtConst::c ) );
    }
    if ( other_b == B0 ) {
        amp = A * EvtComplex( cos( 2.0 * getArg( 0 ) ), sin( 2.0 * getArg( 0 ) ) ) *
                  EvtComplex( 0.0, 1.0 ) *
                  sin( getArg( 1 ) * t / ( 2 * EvtConst::c ) ) +
              getArg( 2 ) * Abar * cos( getArg( 1 ) * t / ( 2 * EvtConst::c ) );
    }

    EvtVector4R p4_parent;

    p4_parent = momv + moms;

    double norm = massv / ( momv.d3mag() * p4_parent.mass() );

    vertex( 0, amp * norm * p4_parent * ( v->epsParent( 0 ) ) );
    vertex( 1, amp * norm * p4_parent * ( v->epsParent( 1 ) ) );
    vertex( 2, amp * norm * p4_parent * ( v->epsParent( 2 ) ) );

    return;
}

std::string EvtSVSCP::getParamName( int i )
{
    switch ( i ) {
        case 0:
            return "weakPhase";
        case 1:
            return "deltaM";
        case 2:
            return "finalStateCP";
        case 3:
            return "Af";
        case 4:
            return "AfPhase";
        case 5:
            return "Abarf";
        case 6:
            return "AbarfPhase";
        default:
            return "";
    }
}

std::string EvtSVSCP::getParamDefault( int i )
{
    switch ( i ) {
        case 3:
            return "1.0";
        case 4:
            return "0.0";
        case 5:
            return "1.0";
        case 6:
            return "0.0";
        default:
            return "";
    }
}