[PWGLF] Selection of phi decay channel in GenMC for closure test (#9551)

Author: scannito

PWGLF/Tasks/Strangeness/phik0shortanalysis.cxx

@@ -141,6 +141,9 @@ struct Phik0shortanalysis {
   // Configurable for RecMC
   Configurable<bool> cfgiskNoITSROFrameBorder{"cfgiskNoITSROFrameBorder", false, "kNoITSROFrameBorder request on RecMC collisions"};
 
+  // Configurable for MC closure
+  Configurable<bool> cfgisGenMCForClosure{"cfgisGenMCForClosure", false, "isGenMCForClosure"};
+
   // Constants
   double massKa = o2::constants::physics::MassKPlus;
   double massPi = o2::constants::physics::MassPiPlus;
@@ -1657,6 +1660,20 @@ struct Phik0shortanalysis {
       for (const auto& mcParticle2 : mcParticles) {
         if (mcParticle2.pdgCode() != 333)
           continue;
+        if (cfgisGenMCForClosure) {
+          auto kDaughters = mcParticle2.daughters_as<aod::McParticles>();
+          if (kDaughters.size() != 2)
+            continue;
+          bool isPosKaon = false, isNegKaon = false;
+          for (const auto& kDaughter : kDaughters) {
+            if (kDaughter.pdgCode() == 321)
+              isPosKaon = true;
+            if (kDaughter.pdgCode() == -321)
+              isNegKaon = true;
+          }
+          if (!isPosKaon || !isNegKaon)
+            continue;
+        }
 
         if (std::abs(mcParticle2.y()) > cfgYAcceptance)
           continue;
@@ -1723,6 +1740,20 @@ struct Phik0shortanalysis {
       for (const auto& mcParticle2 : mcParticles) {
         if (mcParticle2.pdgCode() != 333)
           continue;
+        if (cfgisGenMCForClosure) {
+          auto kDaughters = mcParticle2.daughters_as<aod::McParticles>();
+          if (kDaughters.size() != 2)
+            continue;
+          bool isPosKaon = false, isNegKaon = false;
+          for (const auto& kDaughter : kDaughters) {
+            if (kDaughter.pdgCode() == 321)
+              isPosKaon = true;
+            if (kDaughter.pdgCode() == -321)
+              isNegKaon = true;
+          }
+          if (!isPosKaon || !isNegKaon)
+            continue;
+        }
 
         if (std::abs(mcParticle2.y()) > cfgYAcceptance)
           continue;