Add sigmapi resonance config (#2067)

Co-authored-by: Francesco Mazzaschi <fmazzasc@alipap1.cern.ch>

Author: fmazzasc

MC/config/PWGLF/ini/GeneratorLFSigmaPiResonances.ini

@@ -0,0 +1,7 @@
+[GeneratorExternal]
+fileName=${O2DPG_MC_CONFIG_ROOT}/MC/config/PWGLF/pythia8/generator_pythia8_LF.C
+funcName=generateLF("${O2DPG_MC_CONFIG_ROOT}/MC/config/PWGLF/pythia8/generator/sigmapi_resonances_gun.json", true, 4)
+
+[DecayerPythia8] # after for transport code!
+config[0]=${O2DPG_MC_CONFIG_ROOT}/MC/config/common/pythia8/decayer/base.cfg
+config[1]=${O2DPG_MC_CONFIG_ROOT}/MC/config/PWGLF/pythia8/generator/resonances.cfg

MC/config/PWGLF/pythia8/generator/sigmapi_resonances_gun.json

@@ -0,0 +1,29 @@
+{
+    "lambda(1405)" : {
+        "pdg": 102132,
+        "n": 2,
+        "ptMin": 0.0,
+        "ptMax": 10,
+        "etaMin": -1.2,
+        "etaMax": 1.2,
+        "genDecayed": true
+    },
+    "lambda(1520)" : {
+        "pdg": 102134,
+        "n": 2,
+        "ptMin": 0.0,
+        "ptMax": 10,
+        "etaMin": -1.2,
+        "etaMax": 1.2,
+        "genDecayed": true
+    },
+    "sigma(1385)" : {
+        "pdg": 3214,
+        "n": 2,
+        "ptMin": 0.0,
+        "ptMax": 10,
+        "etaMin": -1.2,
+        "etaMax": 1.2,
+        "genDecayed": true
+    }
+}