Protection added.

[u/mrichter/AliRoot.git] / EVGEN / AliGenMC.cxx

diff --git a/EVGEN/AliGenMC.cxx b/EVGEN/AliGenMC.cxx
index 466f44b21439be3dc7fef765db5d1976540362aa..13339d723b1bcfa62e7173c4b1c7eb1d9fb94e1a 100644 (file)
--- a/EVGEN/AliGenMC.cxx
+++ b/EVGEN/AliGenMC.cxx
@@ -198,13 +198,17 @@ Bool_t AliGenMC::KinematicSelection(TParticle *particle, Int_t flag) const
 {
 // Perform kinematic selection
     Double_t pz    = particle->Pz();
-    Double_t  e    = particle->Energy();
     Double_t pt    = particle->Pt();
     Double_t p     = particle->P();
     Double_t theta = particle->Theta();
     Double_t mass  = particle->GetCalcMass();
     Double_t mt2   = pt * pt + mass * mass;
     Double_t phi   = particle->Phi();
+    Double_t e     = particle->Energy();
+    
+    if (e == 0.)     
+       e = TMath::Sqrt(p * p + mass * mass);
+
     
     Double_t y, y0;
 
@@ -361,7 +365,7 @@ void AliGenMC::Boost()
 //
 
     Double_t beta  = TMath::TanH(fDyBoost);
-    Double_t gamma = 1./TMath::Sqrt(1.-beta*beta);
+    Double_t gamma = 1./TMath::Sqrt((1.-beta)*(1.+beta));
     Double_t gb    = gamma * beta;
 
     //    printf("\n Boosting particles to lab frame %f %f %f", fDyBoost, beta, gamma);