[PWGLF] Update NucleiEfficiencyTask.cxx (#9874)

Author: RafRaf11

PWGLF/Tasks/Nuspex/NucleiEfficiencyTask.cxx

@@ -48,7 +48,6 @@ using namespace o2;
 using namespace o2::track;
 using namespace o2::framework;
 using namespace o2::framework::expressions;
-// using CollisionCandidates = o2::soa::Join<>;
 
 struct NucleiEfficiencyTask {
 
@@ -168,27 +167,11 @@ struct NucleiEfficiencyTask {
 
   //***********************************************************************************
 
-  template <typename CollisionType>
-  int getCentralityMC(CollisionType const& collision)
-  {
-    float multiplicity{0.f};
-    int centrality = 0;
-    float collMult{0.f};
-    collMult = collision.numContrib();
-
-    if (collMult > multiplicity) {
-      centrality = collision.centFT0C();
-      multiplicity = collMult;
-    }
-
-    return centrality;
-  }
-
-  //***********************************************************************************
-
   template <typename McCollisionType, typename McParticlesType>
   void process_MC_gen(const McCollisionType& mcCollision, const McParticlesType& mcParticles)
   {
+    if (mcCollision.posZ() < -cfgCutVertex || mcCollision.posZ() > cfgCutVertex)
+      return;
     MC_gen_reg.fill(HIST("histGenVtxMC"), mcCollision.posZ());
     MC_gen_reg.fill(HIST("histCentrality"), mcCollision.impactParameter());
 
@@ -283,17 +266,14 @@ struct NucleiEfficiencyTask {
   void process_MC_reco(const CollisionType& collision, const TracksType& tracks, const mcParticlesType& /*mcParticles*/)
   {
 
-    int centrality = getCentralityMC(collision);
     if (event_selection_MC_sel8 && !collision.sel8())
       return;
-    if (collision.posZ() > cfgCutVertex)
-      return;
     MC_recon_reg.fill(HIST("histRecVtxMC"), collision.posZ());
     if (!isEventSelected(collision))
       return;
-    if (centrality < minCentrality || centrality > maxCentrality)
+    if (collision.centFT0C() < minCentrality || collision.centFT0C() > maxCentrality)
       return;
-    MC_recon_reg.fill(HIST("histCentrality"), centrality);
+    MC_recon_reg.fill(HIST("histCentrality"), collision.centFT0C());
 
     for (auto& track : tracks) {
       const auto particle = track.mcParticle();