EvtSVVCPLH.cpp

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#include "EvtGenModels/EvtSVVCPLH.hh"

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

#include "EvtGenModels/EvtSVVHelAmp.hh"

#include <stdlib.h>
#include <string>
using std::endl;

std::string EvtSVVCPLH::getName()
{
    return "SVV_CPLH";
}

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

void EvtSVVCPLH::init()
{
    // check that there are 9 arguments
    checkNArg( 9 );
    checkNDaug( 2 );

    checkSpinParent( EvtSpinType::SCALAR );

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

void EvtSVVCPLH::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 ) +
                      getArg( 7 ) * getArg( 7 ) ) );
}

void EvtSVVCPLH::decay( EvtParticle* p )
{
    //added by Lange Jan4,2000
    static EvtId BS0 = EvtPDL::getId( "B_s0" );
    static EvtId BSB = EvtPDL::getId( "anti-B_s0" );

    double t;
    EvtId other_b;

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

    EvtComplex G0P, G1P, G1M;

    G1P = EvtComplex( getArg( 3 ) * cos( getArg( 4 ) ),
                      getArg( 3 ) * sin( getArg( 4 ) ) );
    G0P = EvtComplex( getArg( 5 ) * cos( getArg( 6 ) ),
                      getArg( 5 ) * sin( getArg( 6 ) ) );
    G1M = EvtComplex( getArg( 7 ) * cos( getArg( 8 ) ),
                      getArg( 7 ) * sin( getArg( 8 ) ) );

    EvtComplex lambda_km = EvtComplex( cos( 2 * getArg( 0 ) ),
                                       sin( 2 * getArg( 0 ) ) );

    double cdmt = cos( getArg( 1 ) * t / ( 2 * EvtConst::c ) );
    double sdmt = sin( getArg( 1 ) * t / ( 2 * EvtConst::c ) );

    EvtComplex cG0P, cG1P, cG1M;

    static double ctauL = EvtPDL::getctau( EvtPDL::getId( "B_s0L" ) );
    static double ctauH = EvtPDL::getctau( EvtPDL::getId( "B_s0H" ) );

    //I'm not sure if the fabs() is right when t can be
    //negative as in the case of Bs produced coherently.
    double pt = 1;
    double mt = exp( -fabs( t * ( ctauL - ctauH ) / ( ctauL * ctauH ) ) );

    if ( other_b == BSB ) {
        cG0P = pt * G0P *
               ( cdmt + lambda_km * EvtComplex( 0.0, getArg( 2 ) * sdmt ) );
        cG1P = pt * G1P *
               ( cdmt + lambda_km * EvtComplex( 0.0, getArg( 2 ) * sdmt ) );
        cG1M = mt * G1M *
               ( cdmt - lambda_km * EvtComplex( 0.0, getArg( 2 ) * sdmt ) );
    } else if ( other_b == BS0 ) {
        cG0P = pt * G0P *
               ( cdmt +
                 ( 1.0 / lambda_km ) * EvtComplex( 0.0, getArg( 2 ) * sdmt ) );
        cG1P = pt * G1P *
               ( cdmt +
                 ( 1.0 / lambda_km ) * EvtComplex( 0.0, getArg( 2 ) * sdmt ) );
        cG1M = -mt * G1M *
               ( cdmt -
                 ( 1.0 / lambda_km ) * EvtComplex( 0.0, getArg( 2 ) * sdmt ) );
    } else {
        EvtGenReport( EVTGEN_ERROR, "EvtGen" )
            << "other_b was not BSB or BS0!" << endl;
        ::abort();
    }

    EvtComplex A0, AP, AM;

    A0 = cG0P / sqrt( 2.0 );
    AP = ( cG1P + cG1M ) / sqrt( 2.0 );
    AM = ( cG1P - cG1M ) / sqrt( 2.0 );

    EvtSVVHelAmp::SVVHel( p, _amp2, getDaug( 0 ), getDaug( 1 ), AP, A0, AM );

    return;
}