Fix bug

Author: wang-yuanzhe

PWGLF/TableProducer/Nuspex/decay3bodybuilder.cxx

@@ -754,7 +754,7 @@ struct decay3bodyBuilder {
       auto trackPos = decay3body.template track0_as<TTracksTo>();
       auto trackNeg = decay3body.template track1_as<TTracksTo>();
       auto trackDeuteron = decay3body.template track2_as<TTracksTo>();
-      int protonSign = doLikeSign ? trackDeuteron.sign() : -trackDeuteron.sign();
+      int protonSign = doLikeSign ? -trackDeuteron.sign() : trackDeuteron.sign();
       auto trackProton = protonSign > 0 ? trackPos : trackNeg;
       auto trackPion = protonSign > 0 ? trackNeg : trackPos;