BesEvtGen-00-04-08/src/EvtGen/EvtGenModels/EvtbTosllBallFF.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) 2000      Caltech, UCSB
//
// Module: 
// Description: Form factors for b->sll according to Ali, Ball et al.
//              hep-ph/9910221v2
//
// Modification history:
//
//    Ryd     January 5, 2000         Module created
//
//------------------------------------------------------------------------
#include "EvtGenBase/EvtPatches.hh"
 
#include "EvtGenBase/EvtPatches.hh"
#include "EvtGenBase/EvtPDL.hh"
#include "EvtGenModels/EvtbTosllBallFF.hh"
#include <math.h>
 
EvtbTosllBallFF::EvtbTosllBallFF(){}
 
 
void EvtbTosllBallFF::getScalarFF(EvtId parent, EvtId daught,
                  double t, double mass, 
                  double& fp,double& f0,double& ft){
 
  int model = 1;
  
  double m=EvtPDL::getMeanMass(parent);
  double md=EvtPDL::getMeanMass(daught);
  
  double shat=t/(m*m);
  double shat2=shat*shat;
  double shat3=shat2*shat;
 
  if (daught == EvtPDL::getId(std::string("K+")) ||
      daught == EvtPDL::getId(std::string("K-")) ||
      daught == EvtPDL::getId(std::string("K_S0")) ||
      daught == EvtPDL::getId(std::string("K0")) ||
      daught == EvtPDL::getId(std::string("anti-K0")) ||
      daught == EvtPDL::getId(std::string("K_L0"))
     ) 
 {
   // B --> K form factors
  if (model == 1) {
        //this is Ali-Ball '01
    fp = 0.278*exp(1.568*shat+0.470*shat2+0.885*shat3);
    f0 = 0.278*exp(0.740*shat+0.080*shat2+0.425*shat3);
    ft = 0.300*exp(1.600*shat+0.501*shat2+0.796*shat3);
  }
  if (model == 2) {
        //this is Ali-Ball '99
    fp = 0.319*exp(1.465*shat+0.372*shat2+0.782*shat3);
    f0 = 0.319*exp(0.633*shat-0.095*shat2+0.591*shat3);
    ft = 0.355*exp(1.478*shat+0.373*shat2+0.700*shat3);
  }
  if (model == 3) {
        //QCD sum rules (Colangelo et al)
    fp = 0.25/(1.-t/(5.0*5.0));
    f0 = 0.25/(1.-t/(7.0*7.0));
    ft = - 0.14/((1.0 - t/(5.0*5.0))*(1.0 - t/(7.0*7.0)));
  }
  if (model == 4) {
        // Quark model  (Melikhov et al)         
    fp = 0.36/(1. - 0.048*t + 0.00063*t*t);
    double fm = -0.30/(1. - 0.050*t + 0.00061*t*t);
    f0 = fp + fm*(t/(m*m - md*md));
    ft  = -(m+md)*0.06/(1 -0.049*t + 0.00064*t*t);
  }
  if (model == 5) {
    fp = 0.341/(1. - 1.41*shat + 0.406*shat*shat);
    f0 = 0.341/(1. - 0.41*shat -0.361*shat*shat);
    ft = 0.374/(1. - 1.42*shat + 0.434*shat*shat);
  }
 }
 else if (daught == EvtPDL::getId(std::string("pi+")) ||
      daught == EvtPDL::getId(std::string("pi-")) ||
          daught == EvtPDL::getId(std::string("pi0")) ||
          daught == EvtPDL::getId(std::string("eta")) ||
          daught == EvtPDL::getId(std::string("eta'"))
         )  
 {
   // B --> pi form factors
    fp = 0.261/(1. - 2.03*shat + 1.293*shat*shat);
    f0 = 0.261/(1. - 0.27*shat  -0.752*shat*shat);
    ft = 0.296/(1. - 1.28*shat + 0.193*shat*shat);
 }
  // cout << "shat "<<shat<<"\t"<<"fp "<<fp<<"\t"<<"f0 "<<f0<<"\t"
  //    <<"ft "<<ft<<endl;
 
}
 
 
void EvtbTosllBallFF::getVectorFF(EvtId parent, EvtId daught,
                  double t, double mass, 
                  double& a1,double& a2,double& a0, double& v,
                  double& t1, double& t2, double& t3 ){
 
  int model = 1;
  
  double m=EvtPDL::getMeanMass(parent);
  double md=EvtPDL::getMeanMass(daught);
  
  double shat=t/(m*m);
  double shat2=shat*shat;
 
  if (
      daught == EvtPDL::getId(std::string("K*+")) ||
      daught == EvtPDL::getId(std::string("K*-")) ||
      daught == EvtPDL::getId(std::string("K*0")) ||
      daught == EvtPDL::getId(std::string("anti-K*0"))
     ) 
 {
  if (model == 1) {
        //this is Ali-Ball '01
    a1 = 0.294*exp(0.656*shat+0.456*shat2);
    a2 = 0.246*exp(1.237*shat+0.822*shat2);
    a0 = 0.412*exp(1.543*shat+0.954*shat2);
    v  = 0.399*exp(1.537*shat+1.123*shat2);
    
    t1 = 0.334*exp(1.575*shat+1.140*shat2);
    t2 = 0.334*exp(0.562*shat+0.481*shat2);
    t3 = 0.234*exp(1.230*shat+1.089*shat2);
  }
  if (model == 2) {
        //this is Ali-Ball '99
    a1=0.337*exp(0.602*shat+0.258*shat2);
    a2=0.282*exp(1.172*shat+0.567*shat2);
    a0=0.471*exp(1.505*shat+0.710*shat2);
    v=0.457*exp(1.482*shat+1.015*shat2);
    
    t1=0.379*exp(1.519*shat+1.030*shat2);
    t2=0.379*exp(0.517*shat+0.426*shat2);
    t3=0.260*exp(1.129*shat+1.128*shat2);
  }
  if (model == 3) {
        //QCD sum rules (Colangelo et al)
    a1 = 0.30*(1 - 0.023*t);
    a2 = 0.40*(1 + 0.034*t);
    a0 = 0.3/(1.- t/(4.8*4.8));
    v = 0.47/(1.- t/(5.0*5.0));
    
    t1 = 0.19/(1.-t/(5.3*5.3));
    t2 = 0.19*(1. - 0.02*t);
    t3 = -0.7*(1. + 0.005*t); 
  }
 
  if (model == 4) {
        // Quark model  (Melikhov et al)         
    a1 = 1.6/(1 - 0.0288*t + 0.00028*t*t); a1 = a1/(m+md);
    a2 = (m+md)*0.036/(1. - 0.053*t + 0.00082*t*t);
    double aminus = 0.041/(1. - 0.055*t + 0.00088*t*t);
    double f =  1.60/(1. - 0.0288*t + 0.00028*t*t);
    double aplus = -0.036/(1. - 0.053*t + 0.00082*t*t);
    a0 = (t*aminus + f + (m*m-md*md)*aplus)/(2.0*md);
    v = (m+md)*0.048/(1. - 0.057*t + 0.00085*t*t);
 
    t1 = 0.28/(1. - 0.058*t + 0.0009*t*t);
    double gplus = -0.28/(1. - 0.058*t + 0.0009*t*t);
    double gminus = 0.24/(1. - 0.059*t + 0.00096*t*t);
    t2 = -gplus - (t*gminus)/(m*m-md*md);
    double h = 0.0037/(1. - 0.075*t + 0.0016*t*t);
    t3 = (m+md)*(m+md)*((gminus/(m*m-md*md) - h/2.));
        
  }
  if (model == 5) {
    a1 = 0.337/(1. - 0.60*shat - 0.023*shat*shat);
    a2 = 0.283/(1. - 1.18*shat + 0.281*shat*shat);
    a0 = 0.470/(1. - 1.55*shat + 0.680*shat*shat);
    v  = 0.458/(1. - 1.55*shat + 0.575*shat*shat);
    t1 = 0.379/(1. - 1.59*shat + 0.615*shat*shat);
    t2 = 0.379/(1. - 0.49*shat - 0.241*shat*shat);
    t3 = 0.261/(1. - 1.20*shat + 0.098*shat*shat);
  }
 }
 else if 
  (
   daught == EvtPDL::getId(std::string("rho+")) ||
   daught == EvtPDL::getId(std::string("rho-")) ||
   daught == EvtPDL::getId(std::string("rho0")) ||
   daught == EvtPDL::getId(std::string("omega"))
  ) 
   {
   // B --> rho form factors
    a1 = 0.261/(1. - 0.29*shat - 0.415*shat*shat);
    a2 = 0.223/(1. - 0.93*shat - 0.092*shat*shat);
    a0 = 0.372/(1. - 1.40*shat + 0.437*shat*shat);
    v  = 0.338/(1. - 1.37*shat + 0.315*shat*shat);
    t1 = 0.285/(1. - 1.41*shat + 0.361*shat*shat);
    t2 = 0.285/(1. - 0.28*shat - 0.500*shat*shat);
    t3 = 0.202/(1. - 1.06*shat - 0.076*shat*shat);
   }
  //cout << "shat "<<shat<<"\t"<<"a1 "<<a1<<"\t"<<"a2 "<<a2<<"\t"
  //   <<"a0 "<<a0<<endl;
  // cout << "\t"<<"v  "<<v<<"\t"<<"t1 "<<t1<<"\t"<<"t2 "<<t2<<"\t"
  //   <<"t3 "<<t3<<endl;
}