diff --git a/MC/config/PWGDQ/external/generator/generator_pythia8Onia_PromptSignals_gaptriggered.C b/MC/config/PWGDQ/external/generator/generator_pythia8Onia_PromptSignals_gaptriggered.C
index f37e207f4..74d71bda6 100644
--- a/MC/config/PWGDQ/external/generator/generator_pythia8Onia_PromptSignals_gaptriggered.C
+++ b/MC/config/PWGDQ/external/generator/generator_pythia8Onia_PromptSignals_gaptriggered.C
@@ -173,4 +173,37 @@ FairGenerator*
   // gen->PrintDebug();
 
   return gen;
-}
\ No newline at end of file
+}
+
+FairGenerator*
+  GeneratorPromptJpsi_EvtGenFwdy(int triggerGap, double rapidityMin = -4.3, double rapidityMax = -2.3, bool verbose = false)
+{
+  auto gen = new o2::eventgen::GeneratorEvtGen<o2::eventgen::GeneratorPythia8OniaPromptSignalsGapTriggered>();
+  gen->setTriggerGap(triggerGap);
+  gen->setRapidityRange(rapidityMin, rapidityMax);
+  gen->addHadronPDGs(443);
+  gen->setVerbose(verbose);
+
+  TString pathO2table = gSystem->ExpandPathName("${O2DPG_MC_CONFIG_ROOT}/MC/config/PWGDQ/pythia8/decayer/switchOffJpsi.cfg");
+  gen->readFile(pathO2table.Data());
+  gen->setConfigMBdecays(pathO2table);
+  gen->PrintDebug(true);
+
+  gen->SetSizePdg(1);
+  gen->AddPdg(443, 0);
+
+  gen->SetForceDecay(kEvtDiMuon);
+
+  // set random seed
+  gen->readString("Random:setSeed on");
+  uint random_seed;
+  unsigned long long int random_value = 0;
+  ifstream urandom("/dev/urandom", ios::in|ios::binary);
+  urandom.read(reinterpret_cast<char*>(&random_value), sizeof(random_seed));
+  gen->readString(Form("Random:seed = %llu", random_value % 900000001));
+
+  // print debug
+  // gen->PrintDebug();
+
+  return gen;
+}
diff --git a/MC/config/PWGDQ/ini/Generator_InjectedPromptJpsiFwdy_PythiaOnia_TriggerGap.ini b/MC/config/PWGDQ/ini/Generator_InjectedPromptJpsiFwdy_PythiaOnia_TriggerGap.ini
new file mode 100644
index 000000000..e6f0d7316
--- /dev/null
+++ b/MC/config/PWGDQ/ini/Generator_InjectedPromptJpsiFwdy_PythiaOnia_TriggerGap.ini
@@ -0,0 +1,7 @@
+### The external generator derives from GeneratorPythia8.
+[GeneratorExternal]
+fileName=${O2DPG_MC_CONFIG_ROOT}/MC/config/PWGDQ/external/generator/generator_pythia8Onia_PromptSignals_gaptriggered.C
+funcName=GeneratorPromptJpsi_EvtGenFwdy(5,-4.3,-2.3)
+
+[GeneratorPythia8]
+config=${O2DPG_MC_CONFIG_ROOT}/MC/config/PWGDQ/pythia8/generator/pythia8_onia_triggerGap.cfg
diff --git a/MC/config/PWGDQ/ini/tests/Generator_InjectedPromptJpsiFwdy_PythiaOnia_TriggerGap.C b/MC/config/PWGDQ/ini/tests/Generator_InjectedPromptJpsiFwdy_PythiaOnia_TriggerGap.C
new file mode 100644
index 000000000..2b75fcdbd
--- /dev/null
+++ b/MC/config/PWGDQ/ini/tests/Generator_InjectedPromptJpsiFwdy_PythiaOnia_TriggerGap.C
@@ -0,0 +1,82 @@
+int External()
+{
+    int checkPdgSignal[] = {443};
+    int checkPdgDecay = 13;
+    double rapiditymin = -4.3; double rapiditymax = -2.3;
+    std::string path{"o2sim_Kine.root"};
+    std::cout << "Check for\nsignal PDG " << checkPdgSignal[0] << "\n decay PDG " << checkPdgDecay << "\n";
+    TFile file(path.c_str(), "READ");
+    if (file.IsZombie()) {
+        std::cerr << "Cannot open ROOT file " << path << "\n";
+        return 1;
+    }
+
+    auto tree = (TTree*)file.Get("o2sim");
+    std::vector<o2::MCTrack>* tracks{};
+    tree->SetBranchAddress("MCTrack", &tracks);
+
+    int nLeptons{};
+    int nAntileptons{};
+    int nLeptonPairs{};
+    int nLeptonPairsToBeDone{};
+    int nSignalJpsi{};
+    int nSignalJpsiWithinAcc{};
+    auto nEvents = tree->GetEntries();
+    o2::steer::MCKinematicsReader mcreader("o2sim", o2::steer::MCKinematicsReader::Mode::kMCKine);
+    Bool_t isInjected = kFALSE;
+
+    for (int i = 0; i < nEvents; i++) {
+        tree->GetEntry(i);
+        for (auto& track : *tracks) {
+            auto pdg = track.GetPdgCode();
+	    auto rapidity =  track.GetRapidity();
+	    auto idMoth = track.getMotherTrackId();
+            if (pdg == checkPdgDecay) {
+                // count leptons
+                nLeptons++;
+            } else if(pdg == -checkPdgDecay) {
+                // count anti-leptons
+                nAntileptons++;
+            } else if (pdg == checkPdgSignal[0]) {
+                if(idMoth < 0){
+		// count signal PDG 
+		 nSignalJpsi++;
+                // count signal PDG within acceptance 
+		if(rapidity > rapiditymin && rapidity < rapiditymax)  nSignalJpsiWithinAcc++; 
+		}
+		auto child0 = o2::mcutils::MCTrackNavigator::getDaughter0(track, *tracks);
+                auto child1 = o2::mcutils::MCTrackNavigator::getDaughter1(track, *tracks);
+                if (child0 != nullptr && child1 != nullptr) {
+                    // check for parent-child relations
+                    auto pdg0 = child0->GetPdgCode();
+                    auto pdg1 = child1->GetPdgCode();
+                    std::cout << "First and last children of parent " << checkPdgSignal << " are PDG0: " << pdg0 << " PDG1: " << pdg1 << "\n";
+                    if (std::abs(pdg0) == checkPdgDecay && std::abs(pdg1) == checkPdgDecay && pdg0 == -pdg1) {
+                        nLeptonPairs++;
+                        if (child0->getToBeDone() && child1->getToBeDone()) {
+                            nLeptonPairsToBeDone++;
+                        }
+                    }
+                }
+            }
+        }
+    }
+    std::cout << "#events: " << nEvents << "\n"
+              << "#leptons: " << nLeptons << "\n"
+              << "#antileptons: " << nAntileptons << "\n"
+              << "#signal (prompt Jpsi): " << nSignalJpsi << "; within acceptance " << rapiditymin << " < y < " << rapiditymax << " : " << nSignalJpsiWithinAcc << "\n"
+              << "#lepton pairs: " << nLeptonPairs << "\n"
+              << "#lepton pairs to be done: " << nLeptonPairs << "\n";
+
+
+    if (nLeptonPairs == 0 || nLeptons == 0 || nAntileptons == 0) {
+        std::cerr << "Number of leptons, number of anti-leptons as well as number of lepton pairs should all be greater than 1.\n";
+        return 1;
+    }
+    if (nLeptonPairs != nLeptonPairsToBeDone) {
+        std::cerr << "The number of lepton pairs should be the same as the number of lepton pairs which should be transported.\n";
+        return 1;
+    }
+
+    return 0;
+}
diff --git a/MC/config/common/pythia8/generator/pythia8_hf.cfg b/MC/config/common/pythia8/generator/pythia8_hf.cfg
index 273751f09..899e96b31 100644
--- a/MC/config/common/pythia8/generator/pythia8_hf.cfg
+++ b/MC/config/common/pythia8/generator/pythia8_hf.cfg
@@ -1,7 +1,7 @@
 ### beams
 Beams:idA 2212			# proton
 Beams:idB 2212 			# proton
-Beams:eCM 14000. 		# GeV
+Beams:eCM 13600. 		# GeV
 
 ### processes
 HardQCD:hardccbar on		# scatterings g-g / q-qbar -> c-cbar