Presentation on theme: "Data/Monte Carlo disagreement for Rustem’s Signal Fluctuation variable in the Far Detector (Working Title) Part 2 Philip Rodrigues Oxford MINOS Group Meeting."— Presentation transcript:
Data/Monte Carlo disagreement for Rustem’s Signal Fluctuation variable in the Far Detector (Working Title) Part 2 Philip Rodrigues Oxford MINOS Group Meeting 5 Feb 08
2 Low/High variable Rationale: muon tracks small variation between planes, non-muon tracks larger variation Construction: 1.Exclude first 30% of track planes (to veto shower) 2.Find window around reco’d track: ±4 strips, ±40ns 3.Take all strips in this window (track and non-track) 4.Sort these strips by PH 5.Find mean PH of lower half, mean PH of upper half 6.Low/High = mean of lower half / mean of upper half
3 Outline ND Low/High problem fairly well studied FD still uncertain –Various ad hoc cuts help –Crosstalk looks promising This week: –Is it track modelling or detector modelling?
4 Crosstalk Fixes up low/high distribution Doesn’t fix up everything else Not conclusive: –model is more complicated than the one param I changed!
5 A suggestive distribution Additional small hits are at ± 1 -2 strips from track Diagonal xtalk can jump 1 strip But so can physics
6 A mini mystery Excess of tiny (<0.6 pe) hits in data Looks like crosstalk
8 Crosstalk vs Physics Muxing pattern helps: Simplistic way: P(hit on pixel i | hit on pixel j ) Data/MC:
9 Crosstalk vs Physics 2 Less simplistic: P(small hit on pixel i | track hit on pixel j) 9/6 pair goes opposite way on different tubes! Not very significant (see backup slides)
10 More stats! Cosmics could improve significance, but angular dist, etc ND PMTs, electronics different, but physics should still show… No ±1 strip excess! NN xtalk/afterpulsing (Normalized to #events)
11 Tentative conclusion Extra hits at ±1 strip consistent with crosstalk –But low stats crosstalk map seems to disagree ND shows no extra hits at ±1 strip –Not physics Believe the ND over my ad hoc crosstalk map: –Effect is not physics