1 //--------------------------------------------------------------------------
3 // Module: EvtHQET2FF.cc
5 // Description: form factors for B->D*lnu & B->Dlnu according to HQET
8 // Modification history:
10 // Marco Bomben March 10, 2003 Module created
12 //------------------------------------------------------------------------
14 #include "EvtGenBase/EvtPatches.hh"
15 #include "EvtGenBase/EvtPatches.hh"
16 #include "EvtGenBase/EvtReport.hh"
17 #include "EvtGenModels/EvtHQET2FF.hh"
18 #include "EvtGenBase/EvtId.hh"
20 #include "EvtGenBase/EvtPDL.hh"
25 EvtHQET2FF::EvtHQET2FF(double hqetrho2, double hqetha1_1 , double hqetr1_1, double hqetr2_1) {
35 EvtHQET2FF::EvtHQET2FF(double hqetrho2, double hqetv1_1) {
44 void EvtHQET2FF::getscalarff(EvtId parent,EvtId,
45 double t, double mass, double *f0p, double *f0m) {
48 double mb=EvtPDL::getMeanMass(parent);
49 double w = ((mb*mb)+(mass*mass)-t)/(2.0*mb*mass);
51 // Form factors have a general form, with parameters passed in
52 // from the arguements.
54 // Use disparsion relation parametrization from
55 // I.Caprini, L.Lelluch, M.Neubert, Nucl. Phys. B 530,153(1998)
56 const double z = (sqrt(w+1)-sqrt(2.))/(sqrt(w+1)+sqrt(2.));
57 double v1 = v1_1*(1.- 8.*rho2*z + (51.*rho2-10.)*z*z - (252.*rho2-84.)*z*z*z)
66 void EvtHQET2FF::getvectorff(EvtId parent,EvtId,
67 double t, double mass, double *a1f,
68 double *a2f, double *vf, double *a0f ){
71 double mb=EvtPDL::getMeanMass(parent);
72 double w = ((mb*mb)+(mass*mass)-t)/(2.0*mb*mass);
74 // Form factors have a general form, with parameters passed in
75 // from the arguements.
77 double rstar = ( 2.0*sqrt(mb*mass))/(mb+mass);
79 // Use disparsion relation parametrization from
80 // I.Caprini, L.Lelluch, M.Neubert, Nucl. Phys. B 530,153(1998)
81 const double z = (sqrt(w+1)-sqrt(2.))/(sqrt(w+1)+sqrt(2.));
82 double ha1 =ha1_1*(1.- 8.*rho2*z + (53.*rho2-15.)*z*z - (231.*rho2-91.)*z*z*z);
83 double r1 = r1_1-0.12*(w-1)+0.05*(w-1)*(w-1);
84 double r2 = r2_1+0.11*(w-1)-0.06*(w-1)*(w-1);
87 *a1f = (1.0 - (t/((mb+mass)*(mb+mass))))*ha1;
89 *a2f = (r2/rstar)*ha1;
96 void EvtHQET2FF::gettensorff(EvtId, EvtId, double, double, double*,
97 double*, double*, double*){
99 report(ERROR,"EvtGen") << "Not implemented :gettensorff in EvtHQET2FF.\n";
106 void EvtHQET2FF::getbaryonff(EvtId, EvtId, double, double, double*,
107 double*, double*, double*){
109 report(ERROR,"EvtGen") << "Not implemented :getbaryonff in EvtHQET2FF.\n";