From 637fb38e9d87a3d0ba424ef8ebc41c391b22952b Mon Sep 17 00:00:00 2001
From: Daiki Sekihata <daiki.sekihata@cern.ch>
Date: Sun, 26 Oct 2025 19:00:16 +0100
Subject: [PATCH 1/3] MC/PWGEM: add cfg and ini for VM2ll

---
 MC/config/PWGEM/ini/pythia8_OO_536_VM2ll.ini  |  9 ++++++++
 .../PWGEM/ini/tests/pythia8_OO_536_VM2ll.C    |  8 +++++++
 .../generator/pythia8_OO_536_VM2ll.cfg        | 21 +++++++++++++++++++
 3 files changed, 38 insertions(+)
 create mode 100644 MC/config/PWGEM/ini/pythia8_OO_536_VM2ll.ini
 create mode 100644 MC/config/PWGEM/ini/tests/pythia8_OO_536_VM2ll.C
 create mode 100644 MC/config/PWGEM/pythia8/generator/pythia8_OO_536_VM2ll.cfg

diff --git a/MC/config/PWGEM/ini/pythia8_OO_536_VM2ll.ini b/MC/config/PWGEM/ini/pythia8_OO_536_VM2ll.ini
new file mode 100644
index 000000000..953d909ce
--- /dev/null
+++ b/MC/config/PWGEM/ini/pythia8_OO_536_VM2ll.ini
@@ -0,0 +1,9 @@
+[Diamond]
+width[2]=6.0
+
+[GeneratorExternal]
+fileName=${O2DPG_MC_CONFIG_ROOT}/MC/config/ALICE3/pythia8/generator_pythia8_ALICE3.C
+funcName=generator_pythia8_ALICE3()
+
+[GeneratorPythia8]
+config=${O2DPG_MC_CONFIG_ROOT}/MC/config/PWGEM/pythia8/generator/pythia8_OO_536_VM2ll.cfg
diff --git a/MC/config/PWGEM/ini/tests/pythia8_OO_536_VM2ll.C b/MC/config/PWGEM/ini/tests/pythia8_OO_536_VM2ll.C
new file mode 100644
index 000000000..49c15680f
--- /dev/null
+++ b/MC/config/PWGEM/ini/tests/pythia8_OO_536_VM2ll.C
@@ -0,0 +1,8 @@
+int External() {
+    return 0;
+}
+
+int Pythia8()  
+{  
+  return External();  
+} 
\ No newline at end of file
diff --git a/MC/config/PWGEM/pythia8/generator/pythia8_OO_536_VM2ll.cfg b/MC/config/PWGEM/pythia8/generator/pythia8_OO_536_VM2ll.cfg
new file mode 100644
index 000000000..596a85beb
--- /dev/null
+++ b/MC/config/PWGEM/pythia8/generator/pythia8_OO_536_VM2ll.cfg
@@ -0,0 +1,21 @@
+### OO beams
+Beams:idA = 1000080160
+Beams:idB = 1000080160           
+Beams:eCM = 5360.0                ### energy
+    
+Beams:frameType = 1
+ParticleDecays:limitTau0 = on
+ParticleDecays:tau0Max = 10.      ### match alice: 1cm/c = 10.0mm/c
+
+### Save some CPU at init of jobs
+### To avoid refitting, add the following lines to your configuration file:
+HeavyIon:SigFitNGen = 0
+HeavyIon:SigFitDefPar = 2.15,18.42,0.33
+    
+Random:setSeed = on
+
+# change omega, phi meson's BR below
+223:oneChannel = 1 0.5 0 -11 11
+223:addChannel = 1 0.5 0 -13 13
+333:oneChannel = 1 0.5 0 -11 11
+333:addChannel = 1 0.5 0 -13 13

From f15f3a243c1651056ea56a5a81cdc0073eff7213 Mon Sep 17 00:00:00 2001
From: Daiki Sekihata <daiki.sekihata@cern.ch>
Date: Fri, 7 Nov 2025 16:00:26 +0100
Subject: [PATCH 2/3] Comment out Pythia8 function

Comment out the Pythia8 function to disable it.
---
 MC/config/PWGEM/ini/tests/pythia8_OO_536_VM2ll.C | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/MC/config/PWGEM/ini/tests/pythia8_OO_536_VM2ll.C b/MC/config/PWGEM/ini/tests/pythia8_OO_536_VM2ll.C
index 49c15680f..1fdafa6d3 100644
--- a/MC/config/PWGEM/ini/tests/pythia8_OO_536_VM2ll.C
+++ b/MC/config/PWGEM/ini/tests/pythia8_OO_536_VM2ll.C
@@ -2,7 +2,7 @@ int External() {
     return 0;
 }
 
-int Pythia8()  
-{  
-  return External();  
-} 
\ No newline at end of file
+//int Pythia8()  
+//{  
+//    return External();
+//}

From c079f769fef652a9e9863d1720bbfefa1fbca402 Mon Sep 17 00:00:00 2001
From: Daiki Sekihata <daiki.sekihata@cern.ch>
Date: Mon, 10 Nov 2025 17:37:14 +0100
Subject: [PATCH 3/3] Update pythia8_OO_536_VM2ll.C

---
 .../PWGEM/ini/tests/pythia8_OO_536_VM2ll.C    | 50 ++++++++++++++++++-
 1 file changed, 49 insertions(+), 1 deletion(-)

diff --git a/MC/config/PWGEM/ini/tests/pythia8_OO_536_VM2ll.C b/MC/config/PWGEM/ini/tests/pythia8_OO_536_VM2ll.C
index 1fdafa6d3..9250232c0 100644
--- a/MC/config/PWGEM/ini/tests/pythia8_OO_536_VM2ll.C
+++ b/MC/config/PWGEM/ini/tests/pythia8_OO_536_VM2ll.C
@@ -1,5 +1,53 @@
 int External() {
-    return 0;
+  std::string path{"o2sim_Kine.root"};
+  // Check that file exists, can be opened and has the correct tree
+  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");
+  if (!tree)
+  {
+    std::cerr << "Cannot find tree o2sim in file " << path << "\n";
+    return 1;
+  }
+  std::vector<o2::MCTrack> *tracks{};
+  tree->SetBranchAddress("MCTrack", &tracks);
+
+  // Check if all events are filled
+  auto nEvents = tree->GetEntries();
+  for (Long64_t i = 0; i < nEvents; ++i)
+  {
+    tree->GetEntry(i);
+    if (tracks->empty())
+    {
+      std::cerr << "Empty entry found at event " << i << "\n";
+      return 1;
+    }
+  }
+  // check if each event has at least two oxygen ions
+  for (int i = 0; i < nEvents; i++)
+  {
+    auto check = tree->GetEntry(i);
+    int count = 0;
+    for (int idxMCTrack = 0; idxMCTrack < tracks->size(); ++idxMCTrack)
+    {
+      auto track = tracks->at(idxMCTrack);
+      if (track.GetPdgCode() == 1000080160)
+      {
+        count++;
+      }
+    }
+    if (count < 2)
+    {
+      std::cerr << "Event " << i << " has less than 2 oxygen ions\n";
+      return 1;
+    }
+  }
+
+  return 0;
 }
 
 //int Pythia8()