EvtHQET.cc

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//--------------------------------------------------------------------------
//
// Environment:
//      This software is part of the EvtGen package developed jointly
//      for the BaBar and CLEO collaborations.  If you use all or part
//      of it, please give an appropriate acknowledgement.
//
// Copyright Information: See EvtGen/COPYRIGHT
//      Copyright (C) 1998      Caltech, UCSB
//
// Module: EvtHQET.cc
//
// Description: Routine to implement semileptonic B->D*lnu decays according
//              to the model HQET
//
//   Lange Nov9/01 adding Dlnu and possible (w-1)^2 term
//
//
// Modification history:
//
//    DJL     April 20, 1998        Module created
//
//------------------------------------------------------------------------
//
#include "EvtHQET.hh"
#include "../EvtGenBase/EvtGenKine.hh"
#include "../EvtGenBase/EvtPDL.hh"
#include "../EvtGenBase/EvtParticle.hh"
#include "../EvtGenBase/EvtPatches.hh"
#include "../EvtGenBase/EvtReport.hh"
#include "../EvtGenBase/EvtSemiLeptonicScalarAmp.hh"
#include "../EvtGenBase/EvtSemiLeptonicVectorAmp.hh"
#include "EvtHQETFF.hh"
#include <assert.h>
#include <stdlib.h>
#include <string>
using std::endl;
 
EvtHQET::EvtHQET() : hqetffmodel( 0 ), calcamp( 0 ) {}
 
EvtHQET::~EvtHQET() {
  delete hqetffmodel;
  hqetffmodel = 0;
  delete calcamp;
  calcamp = 0;
}
 
void EvtHQET::getName( std::string& model_name ) { model_name = "HQET"; }
 
EvtDecayBase* EvtHQET::clone() { return new EvtHQET; }
 
void EvtHQET::decay( EvtParticle* p ) {
 
  p->initializePhaseSpace( getNDaug(), getDaugs() );
  calcamp->CalcAmp( p, _amp2, hqetffmodel );
}
 
void EvtHQET::initProbMax() {
 
  EvtId parnum, mesnum, lnum, nunum;
 
  parnum = getParentId();
  mesnum = getDaug( 0 );
  lnum   = getDaug( 1 );
  nunum  = getDaug( 2 );
 
  double mymaxprob = calcamp->CalcMaxProb( parnum, mesnum, lnum, nunum, hqetffmodel );
 
  setProbMax( mymaxprob );
}
 
void EvtHQET::init() {
 
  checkNDaug( 3 );
 
  // We expect the parent to be a scalar
  // and the daughters to be X lepton neutrino
  checkSpinParent( EvtSpinType::SCALAR );
 
  checkSpinDaughter( 1, EvtSpinType::DIRAC );
  checkSpinDaughter( 2, EvtSpinType::NEUTRINO );
 
  EvtSpinType::spintype d1type = EvtPDL::getSpinType( getDaug( 0 ) );
  if ( d1type == EvtSpinType::SCALAR )
  {
    checkNArg( 1, 2 );
    if ( getNArg() == 1 ) hqetffmodel = new EvtHQETFF( getArg( 0 ) );
    else hqetffmodel = new EvtHQETFF( getArg( 0 ), getArg( 1 ) );
    calcamp = new EvtSemiLeptonicScalarAmp;
  }
  else if ( d1type == EvtSpinType::VECTOR )
  {
    checkNArg( 3, 4 );
    if ( getNArg() == 3 ) hqetffmodel = new EvtHQETFF( getArg( 0 ), getArg( 1 ), getArg( 2 ) );
    else hqetffmodel = new EvtHQETFF( getArg( 0 ), getArg( 1 ), getArg( 2 ), getArg( 3 ) );
    calcamp = new EvtSemiLeptonicVectorAmp;
  }
  else
  {
    report( ERROR, "EvtGen" )
        << "HQET model handles only scalar and vector meson daughters. Sorry." << endl;
    ::abort();
  }
}