EvtVectorParticle.cpp

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#include "EvtGenBase/EvtVectorParticle.hh"
 
#include "EvtGenBase/EvtComplex.hh"
#include "EvtGenBase/EvtPDL.hh"
#include "EvtGenBase/EvtReport.hh"
#include "EvtGenBase/EvtVector4C.hh"
 
#include <iostream>
#include <math.h>
#include <stdlib.h>
 
void EvtVectorParticle::init( EvtId part_n, double e, double px, double py,
                              double pz )
{
    m_validP4 = true;
    setp( e, px, py, pz );
    setpart_num( part_n );
 
    m_eps[0].set( 0.0, 1.0, 0.0, 0.0 );
    m_eps[1].set( 0.0, 0.0, 1.0, 0.0 );
    m_eps[2].set( 0.0, 0.0, 0.0, 1.0 );
 
    setLifetime();
}
 
void EvtVectorParticle::init( EvtId part_n, const EvtVector4R& p4 )
{
    m_validP4 = true;
    setp( p4 );
    setpart_num( part_n );
 
    m_eps[0].set( 0.0, 1.0, 0.0, 0.0 );
    m_eps[1].set( 0.0, 0.0, 1.0, 0.0 );
    m_eps[2].set( 0.0, 0.0, 0.0, 1.0 );
    setLifetime();
}
 
void EvtVectorParticle::init( EvtId part_n, const EvtVector4R& p4,
                              const EvtVector4C& epsin1,
                              const EvtVector4C& epsin2,
                              const EvtVector4C& epsin3 )
{
    m_validP4 = true;
    setp( p4 );
    setpart_num( part_n );
 
    m_eps[0] = epsin1;
    m_eps[1] = epsin2;
    m_eps[2] = epsin3;
 
    setLifetime();
}
 
EvtSpinDensity EvtVectorParticle::rotateToHelicityBasis() const
{
    static const EvtVector4C eplus( 0.0, -1.0 / sqrt( 2.0 ),
                                    EvtComplex( 0.0, -1.0 / sqrt( 2.0 ) ), 0.0 );
    static const EvtVector4C ezero( 0.0, 0.0, 0.0, 1.0 );
    static const EvtVector4C eminus( 0.0, 1.0 / sqrt( 2.0 ),
                                     EvtComplex( 0.0, -1.0 / sqrt( 2.0 ) ), 0.0 );
 
    static const EvtVector4C eplusC( eplus.conj() );
    static const EvtVector4C ezeroC( ezero.conj() );
    static const EvtVector4C eminusC( eminus.conj() );
 
    EvtSpinDensity R;
    R.setDim( 3 );
 
    for ( int i = 0; i < 3; i++ ) {
        R.set( 0, i, eplusC * m_eps[i] );
        R.set( 1, i, ezeroC * m_eps[i] );
        R.set( 2, i, eminusC * m_eps[i] );
    }
 
    return R;
}
 
EvtSpinDensity EvtVectorParticle::rotateToHelicityBasis( double alpha,
                                                         double beta,
                                                         double gamma ) const
{
    EvtVector4C eplus( 0.0, -1.0 / sqrt( 2.0 ),
                       EvtComplex( 0.0, -1.0 / sqrt( 2.0 ) ), 0.0 );
    EvtVector4C ezero( 0.0, 0.0, 0.0, 1.0 );
    EvtVector4C eminus( 0.0, 1.0 / sqrt( 2.0 ),
                        EvtComplex( 0.0, -1.0 / sqrt( 2.0 ) ), 0.0 );
 
    eplus.applyRotateEuler( alpha, beta, gamma );
    ezero.applyRotateEuler( alpha, beta, gamma );
    eminus.applyRotateEuler( alpha, beta, gamma );
 
    EvtSpinDensity R;
    R.setDim( 3 );
 
    for ( int i = 0; i < 3; i++ ) {
        R.set( 0, i, eplus.conj() * m_eps[i] );
        R.set( 1, i, ezero.conj() * m_eps[i] );
        R.set( 2, i, eminus.conj() * m_eps[i] );
    }
 
    return R;
}