update default LHE ID for A' to be 1023

[tomeichlersmith]

This update then makes the default configuration of the dark brem model (from our point of view) align with the libraries that are produced by v5.0 of dark-brem-lib-gen.

Users can still use earlier versions of dark-brem-lib-gen, but then they will need to change their configuration script to look for the old LHE ID 622 rather than the new one.

mySim.dark_brem.model.aprime_lhe_id = 622

This change does not alter the PDG ID of the dark photon within our simulation. It will still have the PDG ID of 622 according to Geant4 and the output SimParticle.

I am updating ldmx-sw, here are the details.

What are the issues that this addresses?

This resolves #1521

Check List

• I successfully compiled ldmx-sw with my developments
• I ran my developments and the following shows that they are successful.

When opening this PR as a draft, the signal validation sample action will fail to run because it will be looking for ID 1023 in v4 dark brem libraries where the ID is 622. I'll then edit the CI to use v5 dark brem libraries and then they will succeed when I mark this PR as ready for review.

[tomeichlersmith]

Annoyingly (and why we didn't notice this before), the signal fails to generate any events but then that validation job completes "successfully". I can confirm that the exception that was observed in #1521 is observed here.

   [ ParallelWorld ] 0 debug: Adding : sp_hcal_left_right_PV to parallel world.
  Unrecognized Exception: BadConf : Unable to find any library entries at 'electron_tungsten_MaxE_8.0_MinE_4.0_RelEStep_0.1_UndecayedAP_mA_0.01_run_1'
    The library is either a single CSV file or a directory of LHE files.
    Any individual file can be compressed with `gzip`.
    This means the valid extensions are '.lhe', '.lhe.gz', '.csv', and '.csv.gz'

[tvami]

I'd say we should wait a little bit with merging this into the release, and have a patch before with v4.6, and then maybe in the next patch we should put this in

[tomeichlersmith]

The PR Validation run from after I marked this as Ready for Review did have the signal sample fully generated. The diff is very large because the current gold has no events in it due to this bug, so do not go to that action's page unless you can wait for the large page to load.

Dropping this back to draft so we can re-run validation with an updated patch and compare MG5 to MG4 more directly.

[tvami]

@tomeichlersmith did you rebase this?

[tomeichlersmith]

I have not. I don't know why the rebase was necessary for you, we specifically copy the gold from trunk so it should only matter when the workflow is triggered.

ldmx-sw/.github/workflows/pr_validation.yml

Lines 37 to 39 in 4b012fb

	- name: Git Gold Histograms from trunk
	run: git checkout origin/trunk -- .github/validation_samples/*/gold.root .github/actions/validate/gold_label
	shell: bash

[tvami]

Hmmm interesting, I'm quite confused about the other PR then, but ok sounds good!

[tvami]

CI plots look fine, it's interesting that we give more energy to the dark photon

Consistently less energy for the recoil ele

OTOH the KS test did not flag the pT of the dark photon, and the first bin is hidden in this plot so I cant say much

But, we do see the first bin for the recoil electron, that matches very nicely (if you zoom in)