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[QEE] Remove low-mass events from Z->ll lines

Luke Grazette requested to merge lugrazet-ew-Zcutcomposite into qee_upgrade

Context

There's 'leakage' below 40 GeV making it's way into Hlt2/Sprucing.
This is always cut away anyway offline so we might as well remove it.

image

We believe it's due to the distinction between `CombinationCut` and `CompositeCut` in the ParticleCombiners. `Combination Cut` = before vertex fit, `CompositeCut` = after vertex fit. So the way the combiners are currently set up, it's possible that there's events that pass the CombinationCut of M>40 GeV, but the events post-vertex-fit have a much lower Mass (as small as 5 GeV).

It's been suggested that these are muons from different PVs (we don't include a vertex requirement).

Effect on Rate/BW

Expected to be small, visually per-cent level of the events being selected by the Zmumu line fit into this category, and it's already relatively low rate

Local test over (the same) 10k events, very minor reduction in Rate, not sensitive enough to extrapolate the reduction with any significance but this is clearly negligible/positive change to my eyes.

# Before
[stack]$ cat qee_hlt2_and_spruce_bandwidth_test__qeeupgrade.log | grep DecisionWithOutput | grep Hlt2QEE | grep ZTo
   LAZY_AND: Hlt2QEE_ZToEEFullDecisionWithOutput                                                                       #=10000   Sum=0           Eff=|( 0.000000 +- 0.00000 )%|
   LAZY_AND: Hlt2QEE_ZToMuMuFullDecisionWithOutput                                                                     #=10000   Sum=0           Eff=|( 0.000000 +- 0.00000 )%|
   LAZY_AND: Hlt2QEE_ZToMuMu_DoubleNoMuIDFullDecisionWithOutput                                                        #=10000   Sum=1           Eff=|(0.01000000 +- 0.00999950)%|
   LAZY_AND: Hlt2QEE_ZToMuMu_SingleNoMuIDFullDecisionWithOutput                                                        #=10000   Sum=1           Eff=|(0.01000000 +- 0.00999950)%|

# After
[stack]$ cat qee_hlt2_and_spruce_bandwidth_test__withchanges.log | grep DecisionWithOutput | grep Hlt2QEE | grep ZTo
   LAZY_AND: Hlt2QEE_ZToEEFullDecisionWithOutput                                                                       #=10000   Sum=0           Eff=|( 0.000000 +- 0.00000 )%|
   LAZY_AND: Hlt2QEE_ZToMuMuFullDecisionWithOutput                                                                     #=10000   Sum=0           Eff=|( 0.000000 +- 0.00000 )%|
   LAZY_AND: Hlt2QEE_ZToMuMu_DoubleNoMuIDFullDecisionWithOutput                                                        #=10000   Sum=0           Eff=|( 0.000000 +- 0.00000 )%|
   LAZY_AND: Hlt2QEE_ZToMuMu_SingleNoMuIDFullDecisionWithOutput                                                        #=10000   Sum=0           Eff=|( 0.000000 +- 0.00000 )%|

ToDo

  • Local BW Test
Edited by Luke Grazette

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