New method GetMomentum (Gustavo)

[u/mrichter/AliRoot.git] / STEER / AliESDCaloCluster.cxx

diff --git a/STEER/AliESDCaloCluster.cxx b/STEER/AliESDCaloCluster.cxx
index f575ebce9ae727057bc8fcb26bdc3186c3f8dee1..cfd2b2daa3ff4cb6b51472534257408ee3d63533 100644 (file)
--- a/STEER/AliESDCaloCluster.cxx
+++ b/STEER/AliESDCaloCluster.cxx
@@ -24,6 +24,7 @@
 //   J.L. Klay (LLNL)
 //-----------------------------------------------------------------
 
+#include <TLorentzVector.h>
 #include "AliESDCaloCluster.h"
 
 ClassImp(AliESDCaloCluster)
@@ -203,3 +204,16 @@ void AliESDCaloCluster::SetPid(const Float_t *p) {
     for (Int_t i=0; i<n; i++) fPID[i] = uniform;
 
 }
+
+//_______________________________________________________________________
+void AliESDCaloCluster::GetMomentum(TLorentzVector& p) {
+  // Returns TLorentzVector with momentum of the cluster. Only valid for clusters 
+  // identified as photons or pi0 (overlapped gamma) produced on the vertex
+  
+  Double_t r = TMath::Sqrt(fGlobalPos[0]*fGlobalPos[0]+
+                           fGlobalPos[1]*fGlobalPos[1]+
+                           fGlobalPos[2]*fGlobalPos[2]   ) ; 
+
+  p.SetPxPyPzE( fEnergy*fGlobalPos[0]/r,  fEnergy*fGlobalPos[1]/r,  fEnergy*fGlobalPos[2]/r,  fEnergy) ; 
+  
+}