[PWGLF] Add OO cascade-enriched ini file (#2071)

* [PWGLF] Add OO cascade-enriched ini file

Leverages existing extra-strangeness code and just switches the cfg file to the common OO one.

* Increase omega injection 

to improve efficiency determination for omegas

* Add test for OO cascade configuration

Author: ddobrigk

MC/config/PWGLF/ini/GeneratorLF_Strangeness_OO5360_injection.ini

@@ -0,0 +1,6 @@
+[GeneratorExternal]
+fileName=${O2DPG_MC_CONFIG_ROOT}/MC/config/PWGLF/pythia8/generator_pythia8_extraStrangeness.C
+funcName=generator_extraStrangeness()
+
+[GeneratorPythia8]
+config=${O2DPG_MC_CONFIG_ROOT}/MC/config/common/pythia8/generator/pythia8_OO_536.cfg

MC/config/PWGLF/ini/tests/GeneratorLF_Strangeness_OO5360_injection.C

@@ -0,0 +1,28 @@
+int External()
+{
+    std::string path{"o2sim_Kine.root"};
+
+    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);
+
+    auto nEvents = tree->GetEntries();
+    if (nEvents < 1)
+    {
+        std::cerr << "No events actually generated: not OK!";
+        return 1;
+    }
+    return 0;
+}

MC/config/PWGLF/pythia8/generator_pythia8_extraStrangeness.C

@@ -227,7 +227,7 @@ Double_t boltzPlusPower(const Double_t *x, const Double_t *p)
     // OMEGA ABUNDANCE FIX
     //Adjust relative abundance of multi-strange particles by injecting some
     Double_t lExpectedOmegaToPion = TMath::Max(8.55057e-04 - 7.38732e-04*TMath::Exp(-nChargedParticlesAtMidRap/2.40545e+01) - 6.56785e-05,0.);
-    Double_t lExpectedOmega = 5.0*nPionsAtMidRap*lExpectedOmegaToPion; // extra rich, factor 5
+    Double_t lExpectedOmega = 30.0*nPionsAtMidRap*lExpectedOmegaToPion; // extra rich, factor 30 (omega -> rarer -> smaller Nch bias -> ok to enrich more)
     Int_t lOmegaYield = gRandom->Poisson(3*lExpectedOmega); //factor 3: fix the rapidity acceptance
     m = 1.67245;
     pdg = 3334;