Skip to content

Fix to heavy flavour displaced decays

Katherine Pachal requested to merge kpachal/athena:21.6-fix-displaced-decays into 21.6

This MR brings propagates the bug fix originally discussed in AGENE-1060 from release 19 to release 21. We should sweep it to master as well.

A detailed discussion of the problem can be found in AGENE-2019, but in brief: heavy-flavour-containing particles from displaced decays are currently having their vertex locations re-set to (0,0,0) when they are in reality produced elsewhere. We believe this MR fixes the problem.

A test was done using the job options in ATLMCPROD-9056 for a Higgs portal model with new scalar of mass 60 GeV and lifetime 0.5 ns. The output file (50 events) is here and publicly available: /eos/user/k/kpachal/PhaseIITrack/Signals/run_higgsportal_testfix/higgsportal_125_60_0p5ns/test_evgen.EVNT.root

Tagging @cohm , @jmontejo , @mdanning , @calpigia.

Once this is merged, we'd like to get a new release created quickly so we can start regenerating our buggy samples.

Cheers, Kate

Edited by Katherine Pachal

Merge request reports