AliDecayer realisation for the EvtGen code and EvtGen itself.

[u/mrichter/AliRoot.git] / TEvtGen / EvtGenModels / EvtHQET2FF.cxx

diff --git a/TEvtGen/EvtGenModels/EvtHQET2FF.cxx b/TEvtGen/EvtGenModels/EvtHQET2FF.cxx
new file mode 100644 (file)
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+++ b/TEvtGen/EvtGenModels/EvtHQET2FF.cxx
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+//--------------------------------------------------------------------------
+//
+// Module: EvtHQET2FF.cc
+//
+// Description: form factors for B->D*lnu & B->Dlnu according to HQET 
+//              with dispersive FF
+//
+// Modification history:
+//
+//    Marco Bomben     March 10, 2003        Module created
+//
+//------------------------------------------------------------------------
+// 
+#include "EvtGenBase/EvtPatches.hh"
+#include "EvtGenBase/EvtPatches.hh"
+#include "EvtGenBase/EvtReport.hh"
+#include "EvtGenModels/EvtHQET2FF.hh"
+#include "EvtGenBase/EvtId.hh"
+#include <string>
+#include "EvtGenBase/EvtPDL.hh"
+#include <math.h>
+#include <stdlib.h>
+
+
+EvtHQET2FF::EvtHQET2FF(double hqetrho2, double hqetha1_1 , double hqetr1_1, double hqetr2_1) {
+
+  rho2 = hqetrho2;
+  r1_1 = hqetr1_1;
+  r2_1 = hqetr2_1;
+  ha1_1 = hqetha1_1;
+
+  return;
+}
+
+EvtHQET2FF::EvtHQET2FF(double hqetrho2, double hqetv1_1) {
+
+  rho2 = hqetrho2;
+  v1_1 = hqetv1_1;
+
+  return;
+}
+
+
+void EvtHQET2FF::getscalarff(EvtId parent,EvtId,
+                           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.
+
+  // Use disparsion relation parametrization from 
+  // I.Caprini, L.Lelluch, M.Neubert, Nucl. Phys. B 530,153(1998)
+  const double z = (sqrt(w+1)-sqrt(2.))/(sqrt(w+1)+sqrt(2.));
+  double v1 = v1_1*(1.- 8.*rho2*z + (51.*rho2-10.)*z*z - (252.*rho2-84.)*z*z*z)
+;
+
+  *f0p=v1;
+  *f0m = 0.0;
+
+  return;
+ }
+
+void EvtHQET2FF::getvectorff(EvtId parent,EvtId,
+                           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);
+
+  // Use disparsion relation parametrization from 
+  // I.Caprini, L.Lelluch, M.Neubert, Nucl. Phys. B 530,153(1998)
+  const double z = (sqrt(w+1)-sqrt(2.))/(sqrt(w+1)+sqrt(2.));
+  double ha1 =ha1_1*(1.- 8.*rho2*z + (53.*rho2-15.)*z*z - (231.*rho2-91.)*z*z*z);
+  double r1 = r1_1-0.12*(w-1)+0.05*(w-1)*(w-1);
+  double r2 = r2_1+0.11*(w-1)-0.06*(w-1)*(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;
+ }
+
+void EvtHQET2FF::gettensorff(EvtId, EvtId, double, double, double*, 
+                              double*, double*, double*){
+  
+  report(ERROR,"EvtGen") << "Not implemented :gettensorff in EvtHQET2FF.\n";  
+  ::abort();
+
+}
+
+
+
+void EvtHQET2FF::getbaryonff(EvtId, EvtId, double, double, double*, 
+                              double*, double*, double*){
+  
+  report(ERROR,"EvtGen") << "Not implemented :getbaryonff in EvtHQET2FF.\n";  
+  ::abort();
+
+}