Adding option to fill resolution matrix for 2kstar

Author: prchakra

PWGCF/FemtoUniverse/Core/FemtoUniverseContainer.h

@@ -226,12 +226,16 @@ class FemtoUniverseContainer
   /// \param part2 Particle two
   /// \param mult Multiplicity of the event
   template <bool isMC, typename T>
-  void setPair(T const& part1, T const& part2, const int mult, bool use3dplots, float weight = 1.0f)
+  void setPair(T const& part1, T const& part2, const int mult, bool use3dplots, float weight = 1.0f, bool isiden = false)
   {
     float femtoObs, femtoObsMC;
     // Calculate femto observable and the mT with reconstructed information
     if constexpr (FemtoObs == femto_universe_container::Observable::kstar) {
-      femtoObs = FemtoUniverseMath::getkstar(part1, mMassOne, part2, mMassTwo);
+      if (!isiden) {
+        femtoObs = FemtoUniverseMath::getkstar(part1, mMassOne, part2, mMassTwo);
+      } else {
+        femtoObs = 2.0*FemtoUniverseMath::getkstar(part1, mMassOne, part2, mMassTwo);
+      }
     }
     const float mT = FemtoUniverseMath::getmT(part1, mMassOne, part2, mMassTwo);
 
@@ -242,7 +246,11 @@ class FemtoUniverseContainer
         if (part1.has_fdMCParticle() && part2.has_fdMCParticle()) {
           // calculate the femto observable and the mT with MC truth information
           if constexpr (FemtoObs == femto_universe_container::Observable::kstar) {
-            femtoObsMC = FemtoUniverseMath::getkstar(part1.fdMCParticle(), mMassOne, part2.fdMCParticle(), mMassTwo);
+            if (!isiden) {
+              femtoObsMC = FemtoUniverseMath::getkstar(part1.fdMCParticle(), mMassOne, part2.fdMCParticle(), mMassTwo);
+            } else {
+              femtoObsMC = 2.0*FemtoUniverseMath::getkstar(part1.fdMCParticle(), mMassOne, part2.fdMCParticle(), mMassTwo);
+            }
           }
           const float mTMC = FemtoUniverseMath::getmT(part1.fdMCParticle(), mMassOne, part2.fdMCParticle(), mMassTwo);
 
@@ -260,6 +268,7 @@ class FemtoUniverseContainer
     }
   }
 
+
  protected:
   HistogramRegistry* mHistogramRegistry = nullptr;                                 ///< For QA output
   static constexpr std::string_view FolderSuffix[2] = {"SameEvent", "MixedEvent"}; ///< Folder naming for the output according to EventType