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src/EvtGenModels/EvtRareLbToLllFFlQCD.cpp

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Show All 22 Lines
// Implementation file for class : EvtRareLbToLllFFlQCD // Implementation file for class : EvtRareLbToLllFFlQCD
// //
// 2016-04-19 : Michal Kreps // 2016-04-19 : Michal Kreps
// 2014-10-22 : Michal Kreps // 2014-10-22 : Michal Kreps
//----------------------------------------------------------------------------- //-----------------------------------------------------------------------------
void EvtRareLbToLllFFlQCD::init() void EvtRareLbToLllFFlQCD::init()
{ {
EvtId LbID = EvtPDL::getId( std::string( "Lambda_b0" ) ); const EvtId LbID = EvtPDL::getId( std::string( "Lambda_b0" ) );
EvtId LID = EvtPDL::getId( std::string( "Lambda0" ) ); const EvtId LID = EvtPDL::getId( std::string( "Lambda0" ) );
EvtId BID = EvtPDL::getId( std::string( "B+" ) ); const EvtId BID = EvtPDL::getId( std::string( "B+" ) );
EvtId KID = EvtPDL::getId( std::string( "K-" ) ); const EvtId KID = EvtPDL::getId( std::string( "K-" ) );
double m1 = EvtPDL::getMass( LbID ); const double m1 = EvtPDL::getMass( LbID );
double m2 = EvtPDL::getMass( LID ); const double m2 = EvtPDL::getMass( LID );
double mB = EvtPDL::getMass( BID ); const double mB = EvtPDL::getMass( BID );
double mK = EvtPDL::getMass( KID ); const double mK = EvtPDL::getMass( KID );
t0 = ( m1 - m2 ) * ( m1 - m2 ); t0 = ( m1 - m2 ) * ( m1 - m2 );
tplus = ( mB + mK ) * ( mB + mK ); tplus = ( mB + mK ) * ( mB + mK );
fconsts[0][0] = 0.4221; fconsts[0][0] = 0.4221;
fconsts[0][1] = -1.1386; fconsts[0][1] = -1.1386;
fconsts[0][2] = 5.416; fconsts[0][2] = 5.416;
fconsts[1][0] = 0.5182; fconsts[1][0] = 0.5182;
fconsts[1][1] = -1.3495; fconsts[1][1] = -1.3495;
Show All 34 Linesvoid EvtRareLbToLllFFlQCD::init()
EvtGenReport( EVTGEN_INFO, "EvtGen" ) EvtGenReport( EVTGEN_INFO, "EvtGen" )
<< " EvtRareLbToLll is using form factors from arXiv:1602.01399 " << " EvtRareLbToLll is using form factors from arXiv:1602.01399 "
<< std::endl; << std::endl;
} }
//============================================================================= //=============================================================================
void EvtRareLbToLllFFlQCD::getFF( EvtParticle* parent, EvtParticle* lambda, void EvtRareLbToLllFFlQCD::getFF( const EvtParticle& parent,
EvtRareLbToLllFFBase::FormFactors& FF ) const EvtParticle& lambda,
EvtRareLbToLllFFBase::FormFactors& FF ) const
{ {
// Find the FF information for this particle, start by setting all to zero // Find the FF information for this particle, start by setting all to zero
FF.areZero(); FF.areZero();
double m1 = parent->getP4().mass(); const double m1 = parent.getP4().mass();
double m2 = lambda->getP4().mass(); const double m2 = lambda.getP4().mass();
// double m21=m2/m1; // double m21=m2/m1;
EvtVector4R p4parent; EvtVector4R p4parent;
p4parent.set( parent->mass(), 0, 0, 0 ); p4parent.set( parent.mass(), 0, 0, 0 );
double q2 = ( p4parent - lambda->getP4() ).mass2(); const double q2 = ( p4parent - lambda.getP4() ).mass2();
double massSum = m1 + m2; const double massSum = m1 + m2;
double massDiff = m1 - m2; const double massDiff = m1 - m2;
double massSumSq = massSum * massSum; const double massSumSq = massSum * massSum;
double massDiffSq = massDiff * massDiff; const double massDiffSq = massDiff * massDiff;
double q2Sum = q2 - massSumSq; const double q2Sum = q2 - massSumSq;
double q2Diff = q2 - massDiffSq; double q2Diff = q2 - massDiffSq;
jbackUnsubmitted
Done
Inline Actions

This could be const as well.

jback: This could be const as well.
double f[3]; double f[3];
double g[3]; double g[3];
double h[2]; double h[2];
double htilda[2]; double htilda[2];
for ( int i = 0; i <= 2; ++i ) { for ( int i = 0; i <= 2; ++i ) {
f[i] = formFactorParametrization( q2, fconsts[i][0], fconsts[i][1], f[i] = formFactorParametrization( q2, fconsts[i][0], fconsts[i][1],
▲ Show 20 Lines • Show All 50 Lines • ▼ Show 20 Lines FF.GT_[1] = m1 / q2Diff *
htilda[0] * ( q2 - massSum * massDiff ) ); htilda[0] * ( q2 - massSum * massDiff ) );
FF.GT_[2] = m2 / q2Diff * FF.GT_[2] = m2 / q2Diff *
( -2 * htilda[1] * massDiff * m1 + ( -2 * htilda[1] * massDiff * m1 +
htilda[0] * ( q2 + massSum * massDiff ) ); htilda[0] * ( q2 + massSum * massDiff ) );
return; return;
} }
double EvtRareLbToLllFFlQCD::formFactorParametrization( double q2, double a0, double EvtRareLbToLllFFlQCD::formFactorParametrization( const double q2,
double a1, double pole ) const double a0,
const double a1,
const double pole ) const
{ {
double z = zvar( q2 ); const double z = zvar( q2 );
return 1. / ( 1. - q2 / ( pole * pole ) ) * ( a0 + a1 * z ); return 1. / ( 1. - q2 / ( pole * pole ) ) * ( a0 + a1 * z );
} }
double EvtRareLbToLllFFlQCD::zvar( double q2 ) double EvtRareLbToLllFFlQCD::zvar( const double q2 ) const
{ {
double a = std::sqrt( tplus - q2 ); const double a = std::sqrt( tplus - q2 );
double b = std::sqrt( tplus - t0 ); const double b = std::sqrt( tplus - t0 );
return ( a - b ) / ( a + b ); return ( a - b ) / ( a + b );
} }