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.

Using the reconstructed Energy

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 MC ene. L2 ene. Ene. electron e+ 0.9 1.5 1.37 e- 2.46 2.12 2.6 1.36 1.42 1.44 2.04 ? 2.06 0.749 1.72 1.95 1.99 2.24 2.05 2.34 3.36 3.76 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!)

Energy Resolution, with reco energy

J/y Mass at L2, Mean

J/y Mass at L2, Width

Isolation Cuts, 1-Tower Cluster

Isolation Cuts, 2-Tower Cluster

Isolation Cuts, 3-Tower Cluster

Isolation Cuts, 4-Tower Cluster

Isolation Cuts, 5-Tower Cluster

Isolation Cuts, 6-Tower Cluster

Some numbers on efficiency L0 Reco. Energy> 1.2, L2 Mass > 2.4, 3-Tower Cluster 100-80% 80-60% 60-40% 40-20% 20-0% Events 7970 7436 7673 7676 7751 Accepted J/y 527 513 526 505 L0 Trigger 190 873 4068 7447 7748 L0 Trig. & Accepted 100 165 365 514 L0 & L2 Trigger 113 528 3527 7385 L0 & L2 & Acc 71 139 334 511 L0 Eff. 0.19 0.31 0.71 0.98 1 L2 Eff. 0.84 0.91 0.99 L0 Bg. Rej. 82.7 9.75 1.9 1.03 1.0004 L2 Bg. Rej. 21.14 1.8 1.15 1.01

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