EvtHQETFF.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: EvtHQETFF.cc
//
// Description: form factors for B->D*lnu according to HQET
//
// Modification history:
//
//    DJL     April 17, 1998        Module created
//
//------------------------------------------------------------------------
// 
#include "EvtGenBase/EvtPatches.hh"
#include "EvtGenBase/EvtPatches.hh"
#include "EvtGenBase/EvtReport.hh"
#include "EvtGenModels/EvtHQETFF.hh"
#include "EvtGenBase/EvtId.hh"
#include <string>
#include "EvtGenBase/EvtPDL.hh"
#include <math.h>
 
 
 
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;
 }