Converting TEvtGen to native cmake

[u/mrichter/AliRoot.git] / TEvtGen / EvtGen / EvtGenModels / EvtVll.cpp

diff --git a/TEvtGen/EvtGen/EvtGenModels/EvtVll.cpp b/TEvtGen/EvtGen/EvtGenModels/EvtVll.cpp
new file mode 100644 (file)
index 0000000..f3e517e
--- /dev/null
+++ b/TEvtGen/EvtGen/EvtGenModels/EvtVll.cpp
@@ -0,0 +1,124 @@
+//--------------------------------------------------------------------------
+//
+// 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: EvtVll.cc
+//
+// Description: The decay of a vector meson to two leptons,
+//              or generally, two spin 1/2 particles.
+//              E.g., J/psi -> e+ e-
+//
+// Modification history:
+//
+//    RYD       January 17, 1997       Module created
+//
+//------------------------------------------------------------------------
+//
+#include "EvtGenBase/EvtPatches.hh"
+#include <stdlib.h>
+#include <iostream>
+#include <string>
+#include "EvtGenBase/EvtParticle.hh"
+#include "EvtGenBase/EvtPDL.hh"
+#include "EvtGenBase/EvtGenKine.hh"
+#include "EvtGenModels/EvtVll.hh"
+#include "EvtGenBase/EvtDiracSpinor.hh"
+#include "EvtGenBase/EvtReport.hh"
+#include "EvtGenBase/EvtVector4C.hh"
+
+EvtVll::~EvtVll() {}
+
+std::string EvtVll::getName(){
+
+  return "VLL";     
+
+}
+
+
+EvtDecayBase* EvtVll::clone(){
+
+  return new EvtVll;
+
+}
+
+void EvtVll::init(){
+
+  // check that there are 0 arguments
+  checkNArg(0);
+  checkNDaug(2);
+
+  checkSpinParent(EvtSpinType::VECTOR);
+  
+  checkSpinDaughter(0,EvtSpinType::DIRAC);
+  checkSpinDaughter(1,EvtSpinType::DIRAC);
+
+}
+
+void EvtVll::initProbMax(){
+
+  setProbMax(1.0);
+
+}
+
+void EvtVll::decay(EvtParticle *p){
+
+  p->initializePhaseSpace(getNDaug(),getDaugs());
+
+  EvtParticle *l1, *l2;
+  l1 = p->getDaug(0);
+  l2 = p->getDaug(1);
+
+  EvtVector4C l11, l12, l21, l22;
+  l11=EvtLeptonVCurrent(l1->spParent(0),l2->spParent(0));
+  l12=EvtLeptonVCurrent(l1->spParent(0),l2->spParent(1));
+  l21=EvtLeptonVCurrent(l1->spParent(1),l2->spParent(0));
+  l22=EvtLeptonVCurrent(l1->spParent(1),l2->spParent(1));
+
+  EvtVector4C eps0=p->eps(0);
+  EvtVector4C eps1=p->eps(1);
+  EvtVector4C eps2=p->eps(2);
+
+  double M2=p->mass();
+  M2*=M2;
+  double m2=l1->mass();
+  m2*=m2;
+
+  double norm=1.0/sqrt(2*M2+4*m2-4*m2*m2/M2);
+
+  vertex(0,0,0,norm*(eps0*l11));
+  vertex(0,0,1,norm*(eps0*l12));
+  vertex(0,1,0,norm*(eps0*l21));
+  vertex(0,1,1,norm*(eps0*l22));
+  
+  vertex(1,0,0,norm*(eps1*l11));
+  vertex(1,0,1,norm*(eps1*l12));
+  vertex(1,1,0,norm*(eps1*l21));
+  vertex(1,1,1,norm*(eps1*l22));
+  
+  vertex(2,0,0,norm*(eps2*l11));
+  vertex(2,0,1,norm*(eps2*l12));
+  vertex(2,1,0,norm*(eps2*l21));
+  vertex(2,1,1,norm*(eps2*l22));
+  
+  return;
+
+}
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