EvtVPHOtoVISR Class Reference

#include <EvtVPHOtoVISR.hh>

Inheritance diagram for EvtVPHOtoVISR:

Public Member Functions
	EvtVPHOtoVISR ()
virtual	~EvtVPHOtoVISR ()
void	getName (std::string &name)
EvtDecayBase *	clone ()
void	decay (EvtParticle *p)
void	init ()
void	initProbMax ()
Public Member Functions inherited from EvtDecayAmp
void	makeDecay (EvtParticle *p)
void	setWeight (double weight)
void	vertex (const EvtComplex &amp)
void	vertex (int i1, const EvtComplex &amp)
void	vertex (int i1, int i2, const EvtComplex &amp)
void	vertex (int i1, int i2, int i3, const EvtComplex &amp)
void	vertex (int *i1, const EvtComplex &amp)
virtual	~EvtDecayAmp ()
Public Member Functions inherited from EvtDecayBase
virtual std::string	commandName ()
virtual void	command (std::string cmd)
double	getProbMax (double prob)
double	resetProbMax (double prob)
	EvtDecayBase ()
virtual	~EvtDecayBase ()
virtual bool	matchingDecay (const EvtDecayBase &other) const
EvtId	getParentId ()
double	getBranchingFraction ()
void	disableCheckQ ()
void	checkQ ()
int	getNDaug ()
EvtId *	getDaugs ()
EvtId	getDaug (int i)
int	getNArg ()
int	getPHOTOS ()
void	setPHOTOS ()
void	setVerbose ()
void	setSummary ()
double *	getArgs ()
std::string *	getArgsStr ()
double	getArg (int j)
std::string	getArgStr (int j)
std::string	getModelName ()
int	getDSum ()
int	summary ()
int	verbose ()
void	saveDecayInfo (EvtId ipar, int ndaug, EvtId *daug, int narg, std::vector< std::string > &args, std::string name, double brfr)
void	printSummary ()
void	setProbMax (double prbmx)
void	noProbMax ()
void	checkNArg (int a1, int a2=-1, int a3=-1, int a4=-1)
void	checkNDaug (int d1, int d2=-1)
void	checkSpinParent (EvtSpinType::spintype sp)
void	checkSpinDaughter (int d1, EvtSpinType::spintype sp)
virtual int	nRealDaughters ()

Additional Inherited Members
Static Public Member Functions inherited from EvtDecayBase
static void	findMasses (EvtParticle *p, int ndaugs, EvtId daugs[10], double masses[10])
static void	findMass (EvtParticle *p)
static double	findMaxMass (EvtParticle *p)
Protected Member Functions inherited from EvtDecayBase
bool	daugsDecayedByParentModel ()
Protected Attributes inherited from EvtDecayAmp
EvtAmp	_amp2
Protected Attributes inherited from EvtDecayBase
bool	_daugsDecayedByParentModel

Detailed Description

Definition at line 28 of file EvtVPHOtoVISR.hh.

Constructor & Destructor Documentation

EvtVPHOtoVISR()

EvtVPHOtoVISR::EvtVPHOtoVISR ( )

inline

Definition at line 31 of file EvtVPHOtoVISR.hh.

{}

Referenced by clone().

~EvtVPHOtoVISR()

EvtVPHOtoVISR::~EvtVPHOtoVISR ( )

virtual

Definition at line 32 of file EvtVPHOtoVISR.cc.

{}

Member Function Documentation

clone()

EvtDecayBase * EvtVPHOtoVISR::clone ( )

virtual

Implements EvtDecayBase.

Definition at line 36 of file EvtVPHOtoVISR.cc.

{ return new EvtVPHOtoVISR; }

decay()

void EvtVPHOtoVISR::decay ( EvtParticle * p )

virtual

Implements EvtDecayBase.

Definition at line 57 of file EvtVPHOtoVISR.cc.

                                          {
 
  // take photon along z-axis, either forward or backward.
  // Implement this as generating the photon momentum along
  // the z-axis uniformly
 
  double w = p->mass();
  double s = w * w;
 
  double L     = 2.0 * log( w / 0.000511 );
  double alpha = 1 / 137.0;
  double beta  = ( L - 1 ) * 2.0 * alpha / EvtConst::pi;
 
  // This uses the fact that there is a daughter of the
  // psi(3770)
  assert( p->getDaug( 0 )->getDaug( 0 ) != 0 );
  double md = EvtPDL::getMeanMass( p->getDaug( 0 )->getDaug( 0 )->getId() );
 
  static double mD0 = EvtPDL::getMeanMass( EvtPDL::getId( "D0" ) );
  static double mDp = EvtPDL::getMeanMass( EvtPDL::getId( "D+" ) );
 
  double pgmax = ( s - 4.0 * md * md ) / ( 2.0 * w );
 
  assert( pgmax > 0.0 );
 
  double pgz = 0.99 * pgmax * exp( log( EvtRandom::Flat( 1.0 ) ) / beta );
 
  if ( EvtRandom::Flat( 1.0 ) < 0.5 ) pgz = -pgz;
 
  double k = fabs( pgz );
 
  EvtVector4R p4g( k, 0.0, 0.0, pgz );
 
  EvtVector4R p4res = p->getP4Restframe() - p4g;
 
  double mres = p4res.mass();
 
  double ed = mres / 2.0;
 
  assert( ed > md );
 
  double pd = sqrt( ed * ed - md * md );
 
  // std::cout << "k, mres, w, md, ed, pd:"<<k<<" "<<mres<<" "<<w<<" "<<md<<" "<<ed<<"
  // "<<pd<<std::endl;
 
  p->getDaug( 0 )->init( getDaug( 0 ), p4res );
  p->getDaug( 1 )->init( getDaug( 1 ), p4g );
 
  double sigma =
      beta * pow( 2 / w, beta ) *
      ( 1 + alpha * ( 1.5 * L - 2.0 + EvtConst::pi * EvtConst::pi / 3.0 ) / EvtConst::pi );
 
  double m     = EvtPDL::getMeanMass( p->getDaug( 0 )->getId() );
  double Gamma = EvtPDL::getWidth( p->getDaug( 0 )->getId() );
 
  // mres is the energy of the psi(3770)
 
  double p0 = 0.0;
  if ( ed > mD0 ) p0 = sqrt( ed * ed - mD0 * mD0 );
  double pp = 0.0;
  if ( ed > mDp ) pp = sqrt( ed * ed - mDp * mDp );
 
  double p0norm = sqrt( 0.25 * m * m - mD0 * mD0 );
  double ppnorm = sqrt( 0.25 * m * m - mDp * mDp );
 
  double r0 = 12.7;
  double rp = 12.7;
 
  if ( getNArg() == 2 )
  {
    r0 = getArg( 0 );
    rp = getArg( 1 );
  }
 
  double GammaTot =
      Gamma *
      ( pp * pp * pp / ( 1 + pp * pp * rp * rp ) + p0 * p0 * p0 / ( 1 + p0 * p0 * r0 * r0 ) ) /
      ( ppnorm * ppnorm * ppnorm / ( 1 + ppnorm * ppnorm * rp * rp ) +
        p0norm * p0norm * p0norm / ( 1 + p0norm * p0norm * r0 * r0 ) );
 
  sigma *= pd * pd * pd / ( ( mres - m ) * ( mres - m ) + 0.25 * GammaTot * GammaTot );
 
  assert( sigma > 0.0 );
 
  static double sigmax = sigma;
 
  if ( sigma > sigmax ) { sigmax = sigma; }
 
  static int count = 0;
 
  count++;
 
  // if (count%10000==0){
  //   std::cout << "sigma :"<<sigma<<std::endl;
  //   std::cout << "sigmax:"<<sigmax<<std::endl;
  // }
 
  double norm = sqrt( sigma );
 
  vertex( 0, 0, 0, norm * p->eps( 0 ) * p->epsParent( 0 ).conj() );
  vertex( 1, 0, 0, norm * p->eps( 1 ) * p->epsParent( 0 ).conj() );
  vertex( 2, 0, 0, norm * p->eps( 2 ) * p->epsParent( 0 ).conj() );
 
  vertex( 0, 1, 0, norm * p->eps( 0 ) * p->epsParent( 1 ).conj() );
  vertex( 1, 1, 0, norm * p->eps( 1 ) * p->epsParent( 1 ).conj() );
  vertex( 2, 1, 0, norm * p->eps( 2 ) * p->epsParent( 1 ).conj() );
 
  vertex( 0, 2, 0, norm * p->eps( 0 ) * p->epsParent( 2 ).conj() );
  vertex( 1, 2, 0, norm * p->eps( 1 ) * p->epsParent( 2 ).conj() );
  vertex( 2, 2, 0, norm * p->eps( 2 ) * p->epsParent( 2 ).conj() );
 
  vertex( 0, 0, 1, norm * p->eps( 0 ) * p->epsParent( 0 ).conj() );
  vertex( 1, 0, 1, norm * p->eps( 1 ) * p->epsParent( 0 ).conj() );
  vertex( 2, 0, 1, norm * p->eps( 2 ) * p->epsParent( 0 ).conj() );
 
  vertex( 0, 1, 1, norm * p->eps( 0 ) * p->epsParent( 1 ).conj() );
  vertex( 1, 1, 1, norm * p->eps( 1 ) * p->epsParent( 1 ).conj() );
  vertex( 2, 1, 1, norm * p->eps( 2 ) * p->epsParent( 1 ).conj() );
 
  vertex( 0, 2, 1, norm * p->eps( 0 ) * p->epsParent( 2 ).conj() );
  vertex( 1, 2, 1, norm * p->eps( 1 ) * p->epsParent( 2 ).conj() );
  vertex( 2, 2, 1, norm * p->eps( 2 ) * p->epsParent( 2 ).conj() );
 
  return;
}

getName()

void EvtVPHOtoVISR::getName ( std::string & name )

virtual

Implements EvtDecayBase.

Definition at line 34 of file EvtVPHOtoVISR.cc.

{ model_name = "VPHOTOVISR"; }

init()

void EvtVPHOtoVISR::init ( )

virtual

Reimplemented from EvtDecayBase.

Definition at line 38 of file EvtVPHOtoVISR.cc.

                         {
 
  // check that there are 0 or 2 arguments
  checkNArg( 0, 2 );
 
  // check that there are 2 daughters
  checkNDaug( 2 );
 
  // check the parent and daughter spins
  checkSpinParent( EvtSpinType::VECTOR );
  checkSpinDaughter( 0, EvtSpinType::VECTOR );
  checkSpinDaughter( 1, EvtSpinType::PHOTON );
}

initProbMax()

void EvtVPHOtoVISR::initProbMax ( )

virtual

Reimplemented from EvtDecayBase.

Definition at line 52 of file EvtVPHOtoVISR.cc.

                                {
 
  // setProbMax(100000.0);
}

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The documentation for this class was generated from the following files:

• EvtVPHOtoVISR.hh
• EvtVPHOtoVISR.cc