[PWGDQ] Update VarManager.h to correct the cos theta definition in PP frame (#11451)

KangkanGoswami · alibuild · web-flow · commit df7102fe8f65 · 2025-06-05T15:51:27.000+02:00
Co-authored-by: ALICE Action Bot &lt;alibuild@cern.ch&gt;
diff --git a/PWGDQ/Core/VarManager.h b/PWGDQ/Core/VarManager.h
@@ -2917,7 +2917,7 @@ void VarManager::FillPair(T1 const& t1, T2 const& t2, float* values)
       ROOT::Math::XYZVector yaxis_PP{(v12.Vect()).Unit()};
       ROOT::Math::XYZVector xaxis_PP{(yaxis_PP.Cross(zaxis_PP)).Unit()};
       if (fgUsedVars[kCosThetaPP]) {
-        values[kCosThetaPP] = zaxis_PP.Dot(v_CM);
+        values[kCosThetaPP] = zaxis_PP.Dot(v_CM) / std::sqrt(zaxis_PP.Mag2());
       }
       if (fgUsedVars[kPhiPP]) {
         values[kPhiPP] = TMath::ATan2(yaxis_PP.Dot(v_CM), xaxis_PP.Dot(v_CM));

Original file line number	Diff line number	Diff line change
`@@ -2917,7 +2917,7 @@ void VarManager::FillPair(T1 const& t1, T2 const& t2, float* values)`
`2917`	`2917`	`ROOT::Math::XYZVector yaxis_PP{(v12.Vect()).Unit()};`
`2918`	`2918`	`ROOT::Math::XYZVector xaxis_PP{(yaxis_PP.Cross(zaxis_PP)).Unit()};`
`2919`	`2919`	`if (fgUsedVars[kCosThetaPP]) {`
`2920`		`- values[kCosThetaPP] = zaxis_PP.Dot(v_CM);`
	`2920`	`+ values[kCosThetaPP] = zaxis_PP.Dot(v_CM) / std::sqrt(zaxis_PP.Mag2());`
`2921`	`2921`	`}`
`2922`	`2922`	`if (fgUsedVars[kPhiPP]) {`
`2923`	`2923`	`values[kPhiPP] = TMath::ATan2(yaxis_PP.Dot(v_CM), xaxis_PP.Dot(v_CM));`