[PWGEM/Dilepton] fix isBestMatch for global muons (AliceO2Group#14527)

Author: dsekihat

PWGEM/Dilepton/TableProducer/skimmerPrimaryMuon.cxx

@@ -1255,9 +1255,11 @@ struct associateSameMFT {
           if (global_muon.globalIndex() == muon.globalIndex()) { // don't store myself.
             continue;
           }
-          if (global_muon.collisionId() == muon.collisionId()) {
-            self_Ids.emplace_back(global_muon.globalIndex());
-          }
+          self_Ids.emplace_back(global_muon.globalIndex());
+
+          // if (global_muon.collisionId() == muon.collisionId()) {
+          //   self_Ids.emplace_back(global_muon.globalIndex());
+          // }
         }
         em_same_mft_ids(self_Ids);
         self_Ids.clear();

PWGEM/Dilepton/Utils/EMTrackUtilities.h

@@ -138,7 +138,10 @@ bool isBestMatch(TTrack const& track, TCut const& cut, TTracks const& tracks)
         }
       }
     }
-    if (map_chi2MCHMFT.begin()->first == track.globalIndex()) { // search for minimum matching-chi2
+
+    auto it = std::min_element(map_chi2MCHMFT.begin(), map_chi2MCHMFT.end(), [](decltype(map_chi2MCHMFT)::value_type& l, decltype(map_chi2MCHMFT)::value_type& r) -> bool { return l.second < r.second; }); // search for minimum matching-chi2
+
+    if (it->first == track.globalIndex()) {
       map_chi2MCHMFT.clear();
       return true;
     } else {