[PWGLF] adding cosine term (#13989)

Co-authored-by: ALICE Action Bot <alibuild@cern.ch>

Author: jikim1290

PWGLF/Tasks/Strangeness/lambdaTwoPartPolarization.cxx

@@ -164,6 +164,7 @@ struct lambdaTwoPartPolarization {
     }
 
     histos.add("Ana/Signal", "", {HistType::kTHnSparseF, {ptAxis, ptAxis, detaAxis, dphiAxis, centAxis, cosSigAxis}});
+    histos.add("Ana/SignalCos2", "", {HistType::kTHnSparseF, {ptAxis, ptAxis, detaAxis, dphiAxis, centAxis, cosSigAxis}});
     histos.add("Ana/Acceptance", "", {HistType::kTHnSparseF, {ptAxis, centAxis, RapAxis, cosAccAxis}});
 
     fMultPVCutLow = new TF1("fMultPVCutLow", "[0]+[1]*x+[2]*x*x+[3]*x*x*x - 2.5*([4]+[5]*x+[6]*x*x+[7]*x*x*x+[8]*x*x*x*x)", 0, 100);
@@ -374,6 +375,7 @@ struct lambdaTwoPartPolarization {
         }
 
         histos.fill(HIST("Ana/Signal"), v01.pt(), v02.pt(), v01.yLambda() - v02.yLambda(), dphi, centrality, costhetastar1 * costhetastar2 * weight);
+        histos.fill(HIST("Ana/SignalCos2"), v01.pt(), v02.pt(), v01.yLambda() - v02.yLambda(), dphi, centrality, costhetastar1 * costhetastar2 * std::cos(2.0 * dphi) * weight);
       }
     }
   }