From aee56dc01c48db3cd20b48bbcd6559bbde58d8ec Mon Sep 17 00:00:00 2001
From: Junlee Kim <jikim1290@gmail.com>
Date: Tue, 10 Dec 2024 22:04:18 +0100
Subject: [PATCH] [PWGCF] adding decay mask to second track (#8897)

Co-authored-by: junleekim <junleekim@maccbookjunlee2024.dyndns.cern.ch>
---
 PWGCF/Tasks/correlations.cxx | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/PWGCF/Tasks/correlations.cxx b/PWGCF/Tasks/correlations.cxx
index 067e73d6425..850cdd4d455 100644
--- a/PWGCF/Tasks/correlations.cxx
+++ b/PWGCF/Tasks/correlations.cxx
@@ -267,6 +267,10 @@ struct CorrelationTask {
         for (const auto& track2 : tracks2) {
           if constexpr (std::experimental::is_detected<HasInvMass, typename TTracks2::iterator>::value && std::experimental::is_detected<HasDecay, typename TTracks2::iterator>::value) {
             if (doprocessSame2Prong2Prong) {
+              if (cfgDecayParticleMask != 0 && (cfgDecayParticleMask & (1u << static_cast<uint32_t>(track1.decay()))) == 0u)
+                continue;
+              if ((track1.decay() != 0) || (track2.decay() != 1)) // D0 in trk1, D0bar in trk2
+                continue;
               registry.fill(HIST("invMassTwoPart"), track1.invMass(), track2.invMass(), track1.pt(), track2.pt(), multiplicity);
             }
           }