Adding histograms for accepted pi0 and eta into gamma gamma decay channel with a function

Author: amaringarcia

PWGEM/PhotonMeson/TableProducer/associateMCinfoPhoton.cxx

@@ -66,7 +66,7 @@ struct AssociateMCInfoPhoton {
   Configurable<float> max_rxy_gen{"max_rxy_gen", 100, "max rxy to store generated information"};
   Configurable<bool> requireGammaGammaDecay{"requireGammaGammaDecay", false, "require gamma gamma decay for generated pi0 and eta meson"};
   Configurable<float> cfg_max_eta_photon{"cfg_max_eta_gamma", 0.8, "max eta for photons at PV"};
-  
+
   HistogramRegistry registry{"EMMCEvent"};
 
   void init(o2::framework::InitContext&)
@@ -172,19 +172,15 @@ struct AssociateMCInfoPhoton {
       for (const auto& mcParticle : groupedMcParticles) { // store necessary information for denominator of efficiency
         if ((mcParticle.isPhysicalPrimary() || mcParticle.producedByGenerator()) && std::fabs(mcParticle.y()) < 0.9f && mcParticle.pt() < 20.f) {
           auto binNumber = hBinFinder->FindBin(mcParticle.pt(), std::fabs(mcParticle.y())); // caution: pack
-          size_t lNDaughters = 0; 
-          size_t mesonAccepted = 0;
+
+          bool isMesonAccepted = false;
           if (mcParticle.has_daughters()) {
             auto lDaughters = mcParticle.daughters_as<aod::McParticles>();
-            lNDaughters = lDaughters.size();
-            auto lDaughter0 = lDaughters.begin();
-            if (lNDaughters == 2) {
-              auto lDaughter1 = lDaughters.iteratorAt(1);
-              if ( std::fabs(lDaughter0.eta())< cfg_max_eta_photon &&   std::fabs(lDaughter1.eta()) < cfg_max_eta_photon){
-                mesonAccepted = 1;
-              }
-            } 
-          } 
+
+            if (areTwoPhotonDaughtersAccepted(lDaughters, cfg_max_eta_photon)) {
+              isMesonAccepted = true;
+            }
+          }
           switch (std::abs(mcParticle.pdgCode())) {
             case PDG_t::kGamma:
               registry.fill(HIST("Generated/h2PtY_Gamma"), mcParticle.pt(), std::fabs(mcParticle.y()));
@@ -195,7 +191,7 @@ struct AssociateMCInfoPhoton {
                 continue;
               registry.fill(HIST("Generated/h2PtY_Pi0"), mcParticle.pt(), std::fabs(mcParticle.y()));
               genPi0[binNumber]++;
-              if (mesonAccepted == 1){
+              if (isMesonAccepted) {
                 registry.fill(HIST("Generated/h2PtY_Accepted_Pi0"), mcParticle.pt(), std::fabs(mcParticle.y()));
               }
               break;
@@ -204,7 +200,7 @@ struct AssociateMCInfoPhoton {
                 continue;
               registry.fill(HIST("Generated/h2PtY_Eta"), mcParticle.pt(), std::fabs(mcParticle.y()));
               genEta[binNumber]++;
-              if (mesonAccepted == 1){
+              if (isMesonAccepted) {
                 registry.fill(HIST("Generated/h2PtY_Accepted_Eta"), mcParticle.pt(), std::fabs(mcParticle.y()));
               }
               break;
@@ -513,6 +509,21 @@ struct AssociateMCInfoPhoton {
     fCounters[1] = 0;
   } // end of skimmingMC
 
+  template <typename Daughters>
+  inline bool areTwoPhotonDaughtersAccepted(const Daughters& lDaughters, float maxEta)
+  {
+    if (lDaughters.size() != 2) {
+      return false;
+    }
+
+    auto it0 = lDaughters.begin();
+    auto it1 = it0;
+    ++it1;
+
+    return (std::fabs(it0.eta()) < maxEta &&
+            std::fabs(it1.eta()) < maxEta);
+  }
+
   void processMC_PCM(MyCollisionsMC const& collisions, aod::BCs const& bcs, aod::McCollisions const& mccollisions, aod::McParticles const& mcParticles, TracksMC const& o2tracks, aod::V0PhotonsKF const& v0photons, aod::V0Legs const& v0legs)
   {
     skimmingMC<kPCM>(collisions, bcs, mccollisions, mcParticles, o2tracks, nullptr, v0photons, v0legs, nullptr, nullptr, nullptr);