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J/ Y Simulations for Trigger. Dataset Pythia J/ y mixed into AuAu Hijing ~40K events Mixing takes into account some acceptance filtering Have sample of Hijing unmixed and U mixed (see next talk) Studies: Energy at L2: bias, resolution
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J/Y Simulations for Trigger • Dataset • Pythia J/y mixed into AuAu Hijing • ~40K events • Mixing takes into account some acceptance filtering • Have sample of Hijing unmixed and U mixed (see next talk) • Studies: • Energy at L2: bias, resolution • Mass at L2: cluster size dependence, centrality dependence • Preliminary numbers on Efficiency
How well do we get the e Energy in L2? 1 < E < 5 GeV Peripheral, 100-80% Single Tower Cluster 1 < E < 5 GeV Peripheral, 100-80% 3-Tower Cluster Tower energy obtained from reconstructed towers (after slow simulator). Electron energy from original MC track.
Tower Energy at L2: Energy Bias Here, Tower energy obtained from MC Towers in GEANT. Electron energy from original MC track.
Not too much difference? • Check the MC Energy of the tower, the reco energy (seen at L2) and the MC energy of the electron. L2 can be larger Than original energy More worrysome, Calorimeter reco misses two high towers in the same event!
Bias at E=M/2 MC Energy Rec Energy
Slope of Energy Bias MC Energy Rec Energy
Energy Resolution Not the best statistics here! Can improve by looking at the U files, reach to ~8 GeV. (And if the disks at RCF don’t die!)
Some numbers on efficiency L0 Reco. Energy> 1.2, L2 Mass > 2.4, 3-Tower Cluster
Status & To do • Finalize numbers on rejection factors • Multiplicity, how high does it make sense to run the trigger? • Currently estimate that 100-50% • Resolution is still good • Efficiency is high, and background rejection is probably manageable • Explore the efficiency using isolation cuts • Combine the information and figure out how many J/y per triggered event… • Does it make sense to run the trigger without TPC? • Resolution is worse… but might boost statistics by factors of 10-50!!
Goal for next run… • Catch ‘em and bottle ‘em! Yield w/o trigger: 50 J/y per 1M min-bias events 200 J/y per 1M 10% central events