[PWGLF] chk892Flow: Add new v0 selection cut (#9777)

Author: BongHwi

PWGLF/Tasks/Resonances/chk892Flow.cxx

@@ -176,6 +176,7 @@ struct Chk892Flow {
   Configurable<bool> cfgReturnFlag{"cfgReturnFlag", false, "Return Flag for debugging"};
   Configurable<bool> cSecondaryRequire{"cSecondaryRequire", true, "Secondary cuts on/off"};
   Configurable<bool> cSecondaryArmenterosCut{"cSecondaryArmenterosCut", true, "cut on Armenteros-Podolanski graph"};
+  Configurable<bool> cSecondaryCrossMassHypothesisCut{"cSecondaryCrossMassHypothesisCut", false, "Apply cut based on the lambda mass hypothesis"};
 
   Configurable<bool> cfgByPassDauPIDSelection{"cfgByPassDauPIDSelection", true, "Bypass Daughters PID selection"};
   Configurable<float> cSecondaryDauDCAMax{"cSecondaryDauDCAMax", 0.2, "Maximum DCA Secondary daughters to PV"};
@@ -190,7 +191,8 @@ struct Chk892Flow {
   Configurable<float> cSecondaryDCAtoPVMax{"cSecondaryDCAtoPVMax", 0.4, "Maximum DCA Secondary to PV"};
   Configurable<float> cSecondaryProperLifetimeMax{"cSecondaryProperLifetimeMax", 20., "Maximum Secondary Lifetime"};
   Configurable<float> cSecondaryparamArmenterosCut{"cSecondaryparamArmenterosCut", 0.2, "parameter for Armenteros Cut"};
-  Configurable<float> cSecondaryMassWindow{"cSecondaryMassWindow", 0.03, "Secondary inv mass selciton window"};
+  Configurable<float> cSecondaryMassWindow{"cSecondaryMassWindow", 0.03, "Secondary inv mass selection window"};
+  Configurable<float> cSecondaryCrossMassCutWindow{"cSecondaryCrossMassCutWindow", 0.05, "Secondary inv mass selection window with (anti)lambda hypothesis"};
 
   // K* selection
   Configurable<float> cKstarMaxRap{"cKstarMaxRap", 0.5, "Kstar maximum rapidity"};
@@ -263,7 +265,7 @@ struct Chk892Flow {
     AxisSpec mcLabelAxis = {5, -0.5, 4.5, "MC Label"};
 
     if (cfgReturnFlag) {
-      histos.add("QA/K0sCutCheck", "Check K0s cut", HistType::kTH1D, {AxisSpec{12, -0.5, 11.5, "Check"}});
+      histos.add("QA/K0sCutCheck", "Check K0s cut", HistType::kTH1D, {AxisSpec{13, -0.5, 12.5, "Check"}});
     }
     histos.add("QA/before/CentDist", "Centrality distribution", {HistType::kTH1D, {centAxis}});
     histos.add("QA/before/VtxZ", "Centrality distribution", {HistType::kTH1D, {vtxzAxis}});
@@ -556,6 +558,8 @@ struct Chk892Flow {
     auto lCPA = candidate.v0cosPA();
     auto lPropTauK0s = candidate.distovertotmom(collision.posX(), collision.posY(), collision.posZ()) * MassK0Short;
     auto lMk0s = candidate.mK0Short();
+    auto lMLambda = candidate.mLambda();
+    auto lMALambda = candidate.mAntiLambda();
 
     auto checkCommonCuts = [&]() {
       if (lDauDCA > cSecondaryDauDCAMax)
@@ -580,6 +584,9 @@ struct Chk892Flow {
         return false;
       if (std::fabs(lMk0s - MassK0Short) > cSecondaryMassWindow)
         return false;
+      if (cSecondaryCrossMassHypothesisCut &&
+          ((std::fabs(lMLambda - MassLambda0) < cSecondaryCrossMassCutWindow) || (std::fabs(lMALambda - MassLambda0Bar) < cSecondaryCrossMassCutWindow)))
+        return false;
       return true;
     };
 
@@ -630,6 +637,11 @@ struct Chk892Flow {
         histos.fill(HIST("QA/K0sCutCheck"), 11);
         returnFlag = false;
       }
+      if (cSecondaryCrossMassHypothesisCut &&
+          ((std::fabs(lMLambda - MassLambda0) < cSecondaryCrossMassCutWindow) || (std::fabs(lMALambda - MassLambda0Bar) < cSecondaryCrossMassCutWindow))) {
+        histos.fill(HIST("QA/K0sCutCheck"), 12);
+        returnFlag = false;
+      }
       return returnFlag;
     } else { // normal usage
       if (cSecondaryRequire) {