EvtHQETFF.cc

Go to the documentation of this file.

//--------------------------------------------------------------------------
//
// 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: EvtHQETFF.cc
//
// Description: form factors for B->D*lnu according to HQET
//
// Modification history:
//
//    DJL     April 17, 1998        Module created
//
//------------------------------------------------------------------------
//
#include "EvtHQETFF.hh"
#include "../EvtGenBase/EvtId.hh"
#include "../EvtGenBase/EvtPDL.hh"
#include "../EvtGenBase/EvtPatches.hh"
#include "../EvtGenBase/EvtReport.hh"
#include <math.h>
#include <string>
 
EvtHQETFF::EvtHQETFF( double hqetrho2, double hqetr1, double hqetr2, double quadTerm ) {
 
  rho2 = hqetrho2;
  r1   = hqetr1;
  r2   = hqetr2;
  c    = quadTerm;
 
  return;
}
 
EvtHQETFF::EvtHQETFF( double hqetrho2, double quadTerm ) {
 
  rho2 = hqetrho2;
  c    = quadTerm;
 
  return;
}
 
void EvtHQETFF::getscalarff( EvtId parent, EvtId daught, double t, double mass, double* f0p,
                             double* f0m ) {
 
  double mb = EvtPDL::getMeanMass( parent );
  double w  = ( ( mb * mb ) + ( mass * mass ) - t ) / ( 2.0 * mb * mass );
 
  // Form factors have a general form, with parameters passed in
  // from the arguements.
 
  double ha1 = 1 - rho2 * ( w - 1 ) + c * ( w - 1 ) * ( w - 1 );
 
  *f0p = ha1;
  *f0m = 0.0;
 
  return;
}
 
void EvtHQETFF::getvectorff( EvtId parent, EvtId daught, double t, double mass, double* a1f,
                             double* a2f, double* vf, double* a0f ) {
 
  double mb = EvtPDL::getMeanMass( parent );
  double w  = ( ( mb * mb ) + ( mass * mass ) - t ) / ( 2.0 * mb * mass );
 
  // Form factors have a general form, with parameters passed in
  // from the arguements.
 
  double rstar = ( 2.0 * sqrt( mb * mass ) ) / ( mb + mass );
  double ha1   = 1 - rho2 * ( w - 1 );
 
  *a1f = ( 1.0 - ( t / ( ( mb + mass ) * ( mb + mass ) ) ) ) * ha1;
  *a1f = ( *a1f ) / rstar;
  *a2f = ( r2 / rstar ) * ha1;
  *vf  = ( r1 / rstar ) * ha1;
  *a0f = 0.0;
 
  return;
}