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Trigger Jets: Add Trigger.Jet.LowPtFilter flag to set lowered fastjet minpt for Heavy Ions (ATR-28158)

Claire Antel requested to merge cantel/athena:23.0_HI_lowptfilter into 23.0

Purpose

  • Adding new Trigger.Jet.LowPtFilter flag to switch to a "low pT filter" setting in which fastjet minimum pT for standard antikT4 jets is lowered from default 7 GeV to 4 GeV. This is to avoid reco jet cuts affecting the efficiency of low trigger jet thresholds (HLT_j10) used in Heavy Ion UPC chains. Used a general name for config flag as this may have further use cases beyond HI (such as sample requests for HLT jet calibration to lower pT).
  • Changed filter modifier cut for standard antikT4 jets from 5 GeV to 4 GeV (this is a superfluous additional cut on uncalibrated jet pT)

Impacts

  • No changes expected in default settings, but if flag activated "ConfigFlags.Trigger.Jet.LowPtFilter=True", expect increased HLT jet EDM due to many more jets recorded in output HLT antiKt4 jet containers, and I guess increased rates for very low (HLT_j10) jet trigger chains.
Edited by Claire Antel

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