[PWGLF] Refactor custom nsigma calculation for He3 (#14083)

chiarapinto · alibuild · web-flow · commit 2cd4cab87e76 · 2025-12-04T11:57:04.000+01:00
Co-authored-by: ALICE Builder &lt;alibuild@users.noreply.github.com&gt;
diff --git a/PWGLF/Tasks/Nuspex/antinucleiInJets.cxx b/PWGLF/Tasks/Nuspex/antinucleiInJets.cxx
@@ -1127,8 +1127,7 @@ struct AntinucleiInJets {
             // custom nsigma He3 based on bethe bloch fit of TPC signal
             double tpcSignal = track.tpcSignal();
             double expectedSignalHe3 = tpc::BetheBlochAleph(static_cast<double>(track.tpcInnerParam() * 2. / o2::constants::physics::MassHelium3), cfgBetheBlochParams.value[0], cfgBetheBlochParams.value[1], cfgBetheBlochParams.value[2], cfgBetheBlochParams.value[3], cfgBetheBlochParams.value[4]);
-            double sigmaHe3 = expectedSignalHe3 * cfgBetheBlochParams.value[4];
-            double nSigmaTPCHe3Custom = (tpcSignal - expectedSignalHe3) / sigmaHe3;
+            double nSigmaTPCHe3Custom = ((tpcSignal / expectedSignalHe3) - 1.) / 0.045;
             registryData.fill(HIST("antihelium3_jet_tpc_custom"), 2.0 * pt, nSigmaTPCHe3Custom);
           }
         }
@@ -1223,8 +1222,7 @@ struct AntinucleiInJets {
             // custom nsigma He3 based on bethe bloch fit of TPC signal
             double tpcSignal = track.tpcSignal();
             double expectedSignalHe3 = tpc::BetheBlochAleph(static_cast<double>(track.tpcInnerParam() * 2. / o2::constants::physics::MassHelium3), cfgBetheBlochParams.value[0], cfgBetheBlochParams.value[1], cfgBetheBlochParams.value[2], cfgBetheBlochParams.value[3], cfgBetheBlochParams.value[4]);
-            double sigmaHe3 = expectedSignalHe3 * cfgBetheBlochParams.value[4];
-            double nSigmaTPCHe3Custom = (tpcSignal - expectedSignalHe3) / sigmaHe3;
+            double nSigmaTPCHe3Custom = ((tpcSignal / expectedSignalHe3) - 1.) / 0.045;
             registryData.fill(HIST("antihelium3_ue_tpc_custom"), 2.0 * pt, nSigmaTPCHe3Custom);
           }
         }

Original file line number	Diff line number	Diff line change
`@@ -1127,8 +1127,7 @@ struct AntinucleiInJets {`
`1127`	`1127`	`// custom nsigma He3 based on bethe bloch fit of TPC signal`
`1128`	`1128`	`double tpcSignal = track.tpcSignal();`
`1129`	`1129`	`double expectedSignalHe3 = tpc::BetheBlochAleph(static_cast<double>(track.tpcInnerParam() * 2. / o2::constants::physics::MassHelium3), cfgBetheBlochParams.value[0], cfgBetheBlochParams.value[1], cfgBetheBlochParams.value[2], cfgBetheBlochParams.value[3], cfgBetheBlochParams.value[4]);`
`1130`		`- double sigmaHe3 = expectedSignalHe3 * cfgBetheBlochParams.value[4];`
`1131`		`- double nSigmaTPCHe3Custom = (tpcSignal - expectedSignalHe3) / sigmaHe3;`
	`1130`	`+ double nSigmaTPCHe3Custom = ((tpcSignal / expectedSignalHe3) - 1.) / 0.045;`
`1132`	`1131`	`registryData.fill(HIST("antihelium3_jet_tpc_custom"), 2.0 * pt, nSigmaTPCHe3Custom);`
`1133`	`1132`	`}`
`1134`	`1133`	`}`
`@@ -1223,8 +1222,7 @@ struct AntinucleiInJets {`
`1223`	`1222`	`// custom nsigma He3 based on bethe bloch fit of TPC signal`
`1224`	`1223`	`double tpcSignal = track.tpcSignal();`
`1225`	`1224`	`double expectedSignalHe3 = tpc::BetheBlochAleph(static_cast<double>(track.tpcInnerParam() * 2. / o2::constants::physics::MassHelium3), cfgBetheBlochParams.value[0], cfgBetheBlochParams.value[1], cfgBetheBlochParams.value[2], cfgBetheBlochParams.value[3], cfgBetheBlochParams.value[4]);`
`1226`		`- double sigmaHe3 = expectedSignalHe3 * cfgBetheBlochParams.value[4];`
`1227`		`- double nSigmaTPCHe3Custom = (tpcSignal - expectedSignalHe3) / sigmaHe3;`
	`1225`	`+ double nSigmaTPCHe3Custom = ((tpcSignal / expectedSignalHe3) - 1.) / 0.045;`
`1228`	`1226`	`registryData.fill(HIST("antihelium3_ue_tpc_custom"), 2.0 * pt, nSigmaTPCHe3Custom);`
`1229`	`1227`	`}`
`1230`	`1228`	`}`