14-sep-2004 Midwest Physics Group University of Indiana Triggering and Luminosity Scenarios Maris Abolins Michigan State University

The ATLAS Trigger  Three Level Trigger  Lvl1 - Hardware  Lvl2 - Regions of Interest + Processors  Lvl3 - Processor Farm  Lvl2 + Lvl3 = HLT (High Level Trigger)

Features Lvl1 Trigger Calorimeter electromagnetic - cluster with hadronic veto jet trigger - hadronic cluster & window algorithm particle trigger - jet trigger with isolation  system HLT Trigger - Data available at full readout resolution

Rate Limitations on Lvl1 75 kHz upper limit due to front end electronics ->100 kHz with deadtime ~44 kHz with safety factor due to uncertainty in rates ~25 kHz with cost-driven deferrals of system components ~10 kHz with deferrals and safety factor

Rate Limitations on HLT HLT/DAQ TP (2000) ~540 Hz to storage New Guidelines ~200 Hz to storage due to offline computing considerations

Luminosity Scenarios ATLAS Level1 TDR L~1x10 33 cm -2 s -1 for first year of operation Low luminosity - b-physics program L~1x10 34 cm -2 s -1 thereafter High luminosity - discovery physics Post Initial L~2x10 33 cm -2 s -1

Nomenclature Lvl1 - Capital letters HLT - small letters Isolation -> I E -> E T J -> Jet xE -> Missing E T Number in front indicates no. of objects e.g. 2J55 is 2 jets with E T > 55 GeV at Lvl1 2em15i is 2 isolated em deposits with E T >15 GeV in HLT

Lvl1 Rates (from F. Gianotti before the LHCC on 2-Oct-2002) Selection 95% eff. Thresh. Lvl1 rate (kHz); L=1x10 33 (no def.) Lvl1 rate (kHz); L=2x10 33 (no def.) Lvl1 rate (kHz); L=2x10 33 (def.) MU6,8, MU EM20i,25, EM15i,15,15244 J180,200, J75,90, J55,65,650.2

Lvl1 Rates Continued Selection 95% eff. Thresh. Lvl1 rate (kHz); L=1x10 33 (no def.) Lvl1 rate (kHz); L=2x10 33 (no def.) Lvl1 rate (kHz); L=2x10 33 (def.) J50+xE50,60,600.4 TAU20,25,25+x30222 MU10+EM15i Others(pre-scaled etc.) 555 Total~44~43~25

Things to note Rates are dominated by single  and e To reduce rates these thresholds must be raised Light Higgs is impacted and B physics program is jeopardized Monitoring and calibration triggers ~ %. CDF & DØ Run II are higher~30%

General Physics Trigger Menu for L=2x10 33 from T. Schorner-Sadenius and S. Tapproge, ATL-DAQ Lvl1 SelectionLvl1 Rate [kHz]HLT SelectionHLT Rate [Hz]Examples MU200.8  20i 40 ttH,H->WW,ZZ,qq , W’,Z’,top,Z->ll 2MU”5”0.2 2  10 2  ”5”+ mass etc 10 H->WW,ZZ, Z->ll, B physics EM25i12e25i40ttH,H->WW,W’,Z,top, W->l,Z->ll,H->  2EM15i42e15i 2  20i <1 2 H->WW,ZZ,Z->ll, H->  J2000.2j40010QCD, new phys. 3J900.23j16510“ 4J650.24j11010“ MU10+EM15i0.1  10+e15i 1H->WW,ZZ,tt->4l EM20i+xE20-30?e20i+xE W->e  TAU25+xE302  35+xE45 5 W-> ,Z-> ,new phys J50+xE600.4j70+xE7020SUSY Monitoring520 Total25200

More but rates uncertain Lvl1 SelectionLvl1 Rate [kHz]HLT SelectionHLT Rate [Hz]Examples TAU60?  60 ? H ± ->  2J170?2j350?QCD, new phys FWDJ?fwdj?? xE150?xE200?? E1000? ?? JE1000?jE1000?? EM??+N  J ? e??+N  j ?low rate; thresh. & N tbd MU??+N  J ?  ??+N  j ?low rate; thresh. & N tbd

Additional Triggers High priority, unprescaled, discovery potential, minimal additions to rate Most prominent at Lvl1: EM30,40,50,60 and 2EM30 with partly relaxed isolation criteria Additional Jet, Energy and  triggers are under study

Prescaled Physics, Calibration and Monitoring Triggers Extend physics measurements to lower E T, for example Calibrate efficiency of more restrictive triggers Calibration triggers for energy scale, J/ , .Z- >ee, ,W->jj etc. Minimum bias triggers Monitor triggers for luminosity, vertex position This subject is just starting to be addressed

Conclusions Trigger Menus exist for most likely scenarios at beginning of run Absolute rate estimates are thought to be known within a factor of 2. There are uncertainties due to QCD processes and machine backgrounds Work on Monitoring and Calibration Triggers is just starting