Differential D84 Diff 361 src/EvtGenModels/EvtRareLbToLllFFGutsche.cpp

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src/EvtGenModels/EvtRareLbToLllFFGutsche.cpp


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* This file is part of EvtGen. *		* This file is part of EvtGen. *
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* it under the terms of the GNU General Public License as published by *		* it under the terms of the GNU General Public License as published by *
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Show All 17 Lines
//		//
// 2014-10-21 : Michal Kreps		// 2014-10-21 : Michal Kreps
//-----------------------------------------------------------------------------		//-----------------------------------------------------------------------------

//=============================================================================		//=============================================================================
// Standard constructor, initializes variables		// Standard constructor, initializes variables
//=============================================================================		//=============================================================================

EvtIdSet EvtRareLbToLllFFGutsche::fParents( "Lambda_b0", "anti-Lambda_b0" );
EvtIdSet EvtRareLbToLllFFGutsche::fDaughters( "Lambda0", "anti-Lambda0" );

void EvtRareLbToLllFFGutsche::init()		void EvtRareLbToLllFFGutsche::init()
{		{
fVconsts[0][0] = 0.107;		fVconsts[0][0] = 0.107;
fVconsts[0][1] = 2.27;		fVconsts[0][1] = 2.27;
fVconsts[0][2] = 1.367;		fVconsts[0][2] = 1.367;
fVconsts[1][0] = 0.043;		fVconsts[1][0] = 0.043;
fVconsts[1][1] = 2.411;		fVconsts[1][1] = 2.411;
fVconsts[1][2] = 1.531;		fVconsts[1][2] = 1.531;
Show All 33 Lines	void EvtRareLbToLllFFGutsche::init()

EvtGenReport( EVTGEN_INFO, "EvtGen" )		EvtGenReport( EVTGEN_INFO, "EvtGen" )
<< " EvtRareLbToLll is using form factors from arXiv:1301.3737 "		<< " EvtRareLbToLll is using form factors from arXiv:1301.3737 "
<< std::endl;		<< std::endl;
}		}

//=============================================================================		//=============================================================================

void EvtRareLbToLllFFGutsche::getFF( EvtParticle* parent, EvtParticle* lambda,		void EvtRareLbToLllFFGutsche::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();

/*		/*
if ( ! ( fParents.contains(parent->getId()) &&		if ( ! ( fParents.contains(parent->getId()) &&
fDaughters.contains(lambda->getId()) ) )		fDaughters.contains(lambda->getId()) ) )
{		{
EvtGenReport(EVTGEN_ERROR,"EvtGen") << " EvtRareLbToLllFFGutsche: Unknown mother and/or daughter. " << std::endl;		EvtGenReport(EVTGEN_ERROR,"EvtGen") << " EvtRareLbToLllFFGutsche: Unknown mother and/or daughter. " << std::endl;
return;		return;
}		}
*/		*/

double m1 = parent->getP4().mass();		const double m1 = parent.getP4().mass();
double m2 = lambda->getP4().mass();		const double m2 = lambda.getP4().mass();
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 m21 = m2 / m1;		const double m21 = m2 / m1;
double shat = q2 / m1 / m1;		const double shat = q2 / m1 / m1;

double fV[3];		double fV[3];
double fA[3];		double fA[3];
for ( int i = 0; i <= 2; ++i ) {		for ( int i = 0; i <= 2; ++i ) {
fV[i] = formFactorParametrization( shat, fVconsts[i][0], fVconsts[i][1],		fV[i] = formFactorParametrization( shat, fVconsts[i][0], fVconsts[i][1],
fVconsts[i][2] );		fVconsts[i][2] );
fA[i] = formFactorParametrization( shat, fAconsts[i][0], fAconsts[i][1],		fA[i] = formFactorParametrization( shat, fAconsts[i][0], fAconsts[i][1],
fAconsts[i][2] );		fAconsts[i][2] );
Show All 22 Lines	*/

FF.GT_[0] = -fTA[1] * ( m1 - m2 ) + fTA[0] * ( q2 / m1 );		FF.GT_[0] = -fTA[1] * ( m1 - m2 ) + fTA[0] * ( q2 / m1 );
FF.GT_[1] = -fTA[1] * m1 + fTA[0] * ( m1 + m2 );		FF.GT_[1] = -fTA[1] * m1 + fTA[0] * ( m1 + m2 );
FF.GT_[2] = -fTA[0] * m2 * m21 - m2 * ( fTA[0] + fTA[1] );		FF.GT_[2] = -fTA[0] * m2 * m21 - m2 * ( fTA[0] + fTA[1] );

return;		return;
}		}

double EvtRareLbToLllFFGutsche::formFactorParametrization( double s, double f0,		double EvtRareLbToLllFFGutsche::formFactorParametrization( const double s,
double a, double b )		const double f0,
		const double a,
		const double b ) const
{		{
return f0 / ( 1 - a * s + b * s * s );		return f0 / ( 1 - a * s + b * s * s );
}		}