1. Update FTK Meeting 05/02/06 Erik Brubaker U of Chicago

2. May 2, 2006FTK Meeting2 Physics Case Overview LVL1 LVL2 No FTK (TDR) FTK 1j290 3j130 4j90  Thresh To ?? 0.6 kHz~5 kHz 1j290 3j130 4j90  Thresh + b-tags +  ID 280 Hz 100 kHz total 2000 Hz total More modern baseline has tracking at LVL2. Time budget is 10 ms/evt at LVL2. Even regional tracking may exceed this…

3. May 2, 2006FTK Meeting3 Physics Case Statement #1 FTK vs TDR menus, i.e. no tracking at LVL2—ignore timing. Statement #2 FTK vs nominal LVL2, incl. tracking. Need: FTK allows b-jet (  ) ID w/  b,  c,  q,  . Correlation w/ offline? Depends on environment LVL1 trigger rate, driven by multijet evts, estimated using modern generator + parametrization of full ATLAS LVL1 simulation. Fix LVL2 output rate. Limit LVL1 output rate to sth reasonable. Optimize LVL1 cuts & LVL2 tagging reqs, maximizing signal acceptance/ significance. Same as stmt #1, but add trigger timing into the eqs. Hard to estimate, large uncertainties. But more realistic, stronger case.

4. May 2, 2006FTK Meeting4 Estimating LVL1 rates LVL1 rate ≈ LVL1 QCD rate. Jets 3 & 4 important for our processes  Use generator w/ ME description of these jets; also need appropriate ME/PS matching: Sherpa. Rates may be dominated by tails of LVL1 response.  Use fast simulation of multijets, parametrize response of LVL1 using fully simulated dijet events.

5. May 2, 2006FTK Meeting5 Sherpa+ATLFAST status 10M evts produced using 2  2 + 2  3 ME processes, with y cut = [20, 25] GeV. –Also 10M with just 2  2 ME, y cut = 25 GeV for comparison. –2  2 + 2  3 + 2  4 ME is ready for production, but tier2 condor problems causing delay. Known problems/questions (waiting to hear from authors): –ME does not include b quarks. Should be easy to add. –UE/MPI turned off by default. Does Sherpa include a model reasonable for LHC? –Error messages on ~2% of events. Relevant?

6. May 2, 2006FTK Meeting6 LVL1 Jet Trigger Response Updated parametrization for jet response available, using 11.0.42. http://hep.uchicago.edu/~brubaker/misc/useFitFunction.C The total pass rate is dominated by a small fraction of the Sherpa events. So statistics can still be a problem. 10M looks OK, here for a 4j40 LVL1 trigger. Now using uncalibrated, unsmeared ATLFAST jets as starting point. –Calibration made biggest difference. New CSC dijet samples are finishing up on CAFs around the world. –Big problems getting at data in ATLAS…

7. May 2, 2006FTK Meeting7 LVL1 Jet Trigger Response (2) 10.3.0 11.0.41 J6 LVL1 jet trig resp

8. May 2, 2006FTK Meeting8 LVL1 Tau Trigger Response Tau-trigger response fit in progress. –Could LVL1 trig rate get sizeable contribution from real taus? If so, need  parametrization. ATLFAST jet p T (GeV)  cluster E T response LVL1 t E T (GeV) ATLFAST jet p T (GeV)

9. May 2, 2006FTK Meeting9 Trigger Timing Issues http://hepunx.rl.ac.uk/atlasuk/simulation/level2/ meetings/PESAlvl2IDswReview2005/TIMENOT E/l2time_note.pdf : LVL2 tracking timing note, summer 2005.

10. May 2, 2006FTK Meeting10 Timing prospects Table on previous page is time per RoI, using 0.2x0.2 size. –They show potential factor of 2 improvements. –Adjust for larger RoI size to do b-tagging: x5. –Adjust for # of RoI per typical event: x4. So that makes 120 ± 100 ms per event—budget is 10 ms! John Baines guesses another factor of 2 possible. $1MQ: What is the irreducible time per event, even if FTK provides tracks? Must be < 10 ms…

11. May 2, 2006FTK Meeting11 Next steps Physics case note started. Apply everything to H  hh  4b channel. Improvements to sherpa samples and parametrizations if not too disruptive or time- consuming. Incoming UC grad student can work on VBF H  bb.

12. May 2, 2006FTK Meeting12 Reconstructed m h/H for bkgd New large Sherpa sample w/ new LVL1 parametrization StartTrigB tagsmhmh mHmH # Events1.08e+0753070.00690.00530.00089 Cut eff. 0.0% 77.4%16.6%