Generate TPC loopers only in the background transport when embedding

This avoids the double counting of TPC loopers in embedding productions.

- Background and signal both generated loopers covering the whole timeframe.
- The signal transport now gets GenTPCLoopers.loopersVeto=true.
- GenTPCLoopers settings given with -confKey are applied to the background.
- A veto given for either transport switches loopers off in both.
- The background loopers now use -colBkg as collision system, not -col.

https://its.cern.ch/jira/browse/O2-7272

Co-authored-by: Marco Giacalone <mgiacalo@gmail.com>
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Author: 3 people

MC/bin/o2dpg_sim_workflow.py

@@ -528,6 +528,22 @@ def extractVertexArgs(configKeyValuesStr, finalDiamondDict):
 COLTYPEBKG=args.colBkg
 havePbPb = (COLTYPE == 'PbPb' or (doembedding and COLTYPEBKG == "PbPb"))
 
+# TPC loopers are a background continuous in time: with embedding they are generated
+# by the background transport only, otherwise background and signal both cover the timeframe
+if doembedding:
+   def loopersKeys(confkey):
+      return [kv.strip() for kv in confkey.split(';') if kv.strip().startswith('GenTPCLoopers.')]
+   def loopersVetoed(confkey):
+      return any(kv.split('=')[0].strip() == 'GenTPCLoopers.loopersVeto' and kv.split('=')[1].strip().lower() in ('true', '1')
+                 for kv in loopersKeys(confkey))
+   if loopersVetoed(args.confKey) or loopersVetoed(args.confKeyBkg):
+      print('o2dpg_sim_workflow: TPC loopers switched off for background and signal')
+      args.confKeyBkg = args.confKeyBkg + ';GenTPCLoopers.loopersVeto=true'
+   else:
+      # loopers settings given for the signal apply to the background; the background's own settings take precedence
+      args.confKeyBkg = ';'.join(loopersKeys(args.confKey) + ['GenTPCLoopers.colsys=' + COLTYPEBKG, args.confKeyBkg])
+   args.confKey = args.confKey + ';GenTPCLoopers.loopersVeto=true'
+
 workflow={}
 workflow['stages'] = []