FAMUS Special Run 148451 (this slide is from previous meeting)

1. FAMUS Special Run 148451(this slide is from previous meeting) • Run is collected early March with 1mu and 2mu forward muon triggers • Total number of events is 402k • Good beam conditions, trigger rates, Examine plots during the run • Reconstructed on the farms with P10.15.01 • Preliminary results of scanning • Two major classes of events: • combinatoric • muon tracks: ~64% of events • ~2% of events with 1mu trigger have no scintillator hits in A or B layers (?) • Selected “gold” scanned sample to estimate muon efficiency • with “loose” cuts the efficiency is below 50% ?! Was about 90% for 10.11 • two reco samples: • “original” with 23k events (reco ~mid. March) • “latest” with ~120k events (reco ~early April) • clear difference for these two samples in almost all distributions • Summary • raw data looks OK • something is affecting muon reconstruction on the farms (crashes? Different versions?)

2. FAMUS Reco in p10.15.01 • Major reason for difference with previous scanning • large admixture of events with no fast_z requirement • this trigger has larger backgrounds in low Pt region (below 3GeV/c) • above 3GeV/c backgrounds are well below 10% • most problematic area is below 2GeV/c • If we select events from run 148451 with 1mu&fz requirement (“apples to apples”) • medium cuts efficiency for gold “scanned” events is 91+-4% • similar to run 131798 reco’ed with p10.11 • about 50% of events have muon reconstructed off line (L1 muon trigger “purity”) • Summary • within errors there is no difference in single muon reconstruction efficiency on the farms between p10.11 (run 131798) and p10.15.01 (run 148451) • reconstruction efficiency for p10.15.01 for “medium” cuts is reasonably high ~91% • could be even higher, as some backgrounds might be even in fz sample • scanning has to be used with caution • still could not reco all files from 148451 - large number of crashes on the farm