/home/bes3soft/bes3soft/Boss/7.0.2/dist/7.0.2/Generator/BesEvtGen/BesEvtGen-00-03-58/src/EvtGen/EvtGenModels/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;
 }

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