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Draft: Charm changes for start of 2025 data-taking

Carlos Eduardo Cocha Toapaxi requested to merge charm_2025_reopt into master

Goals

MR collecting all modifications to HLT2 lines aiming to reduce the bandwidth/rate consumption detailed in #876 and %Reoptimised Hlt2 selections for 2025: "lossless" first pass

For lines with exclusive retention rate of 0 would be worth it to check the overlap with other lines.

Contributing

If you want to contribute to this MR, please open a new MR and target the charm_2025_reopt branch and explain your goals.

All the additions need to be tested locally, including:

  • Impact on the bandwidth and rate: previous and new rates and bandwidths, respectively. This must be tested using the HLT1 filtered (1.3 MHz) mdfs available at /eos/lhcb/wg/rta/WP3/mdfs_hlt1filtered_307586. To do so, it is recommended to use this snippet.
  • In case of the usage of PersistReco, it has to be well justified.
  • (optional) Impact on the throughput: comparing the time with the execution of master with no extra modifications.
  • (optional) Determine efficiencies: if there is simulation already available, it will be interesting to know the efficiencies so we ensure that there is no bug in the selections.

Do not rebase or force-push to this branch without the consent of the liaisons @lpica @aanelli and @cacochat, since this might lead to losses on the changes

Changes

hexaquarks @ipolyako !4302 (merged)

  • replace PID cuts with PROBNN
  • split all lines into RS and WS, put additional prescale of 0.5 of those WS lines with more than 1 decay mode
  • tighten LTIME and removed prescale in Ps/Hs/Hss lines
  • tighten PROBNN and (sum)PT cuts for PsToPpPimPim line (probably 20% of BW)
  • tighten selection on PT and VCHI2 for Ks and Lambda on top of those in standart_particles
  • tighten cuts on (sum)PT and IPCHI2 on all exclusive Hq lines
  • for detached pp and LamP lines: replace full PersistReco with saving only Long(Downstream)Protos and Long(Downstream)Tracks, relax IPCHI2 < 100 cut given that's its only partially reconstructed thing

d0_to_hh mu-tagged modes (and related D0 builders) @fbetti !4456 (merged)

  • increase PID_K cut of kaons from 0 to 2
  • increase MINIPCHI2CUT cut on D0 children from 9 to 20
  • tighten the mass window of D0 from 1715-2015 to 1780-1950 MeV (and similar in CombinationCut)
  • tighten D_END_VZ - B_END_VZ from -3 to -1.2 mm
Edited by Federico Betti

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