[PWGEM/Dilepton] add chi2 cut in testPV.cxx

Author: dsekihat

PWGEM/Dilepton/Tasks/testPV.cxx

@@ -41,6 +41,7 @@ struct testPV {
   struct : ConfigurableGroup {
     std::string prefix = "eventCut";
     Configurable<int> cfgEventGeneratorId{"cfgEventGeneratorId", -1, "event generator index. e.g. select gap/signal events"};
+    Configurable<float> cfgChi2PerNcontribMax{"cfgChi2PerNcontribMax", 1e+10, "max. chi2/Ncontrib of PV"};
     Configurable<float> cfgZvtxMin{"cfgZvtxMin", -10.f, "min. Zvtx"};
     Configurable<float> cfgZvtxMax{"cfgZvtxMax", 10.f, "max. Zvtx"};
     Configurable<bool> cfgRequireFT0AND{"cfgRequireFT0AND", true, "require FT0AND"};
@@ -136,6 +137,9 @@ struct testPV {
     if (eventCut.cfgRequireVertexTOFmatched && !collision.selection_bit(o2::aod::evsel::kIsVertexTOFmatched)) {
       return false;
     }
+    if (collision.chi2() / collision.numContrib() > eventCut.cfgChi2PerNcontribMax) {
+      return false;
+    }
     return true;
   }