Update

FTK Meeting

05/02/06

Erik Brubaker

U of Chicago

May 2, 2006 FTK Meeting 2

Physics Case Overview

LVL1

LVL2

No FTK(TDR)

FTK

1j2903j1304j90

ThreshTo ??

0.6 kHz ~5 kHz

1j2903j1304j90

Thresh+ b-tags+ ID

280 Hz280 Hz

100 kHztotal

2000 Hztotal

More modernbaseline hastracking atLVL2.

Time budgetis 10 ms/evtat LVL2.Even regionaltracking mayexceed this…

May 2, 2006 FTK Meeting 3

Physics CaseStatement #1

FTK vs TDR menus,i.e. no tracking atLVL2—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, drivenby multijet evts, estimatedusing modern generator +parametrization of fullATLAS LVL1 simulation.

Fix LVL2 outputrate.

Limit LVL1 outputrate to sth reasonable.

Optimize LVL1 cuts& LVL2 tagging reqs, maximizing signal acceptance/significance.

Same as stmt #1,but add triggertiming into the eqs.

Hard to estimate,large uncertainties.

But more realistic,stronger case.

May 2, 2006 FTK Meeting 4

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.

May 2, 2006 FTK Meeting 5

Sherpa+ATLFAST status• 10M evts produced using 22 + 23 ME processes, with

ycut = [20, 25] GeV.

– Also 10M with just 22 ME, ycut = 25 GeV for comparison.

– 22 + 23 + 24 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?

May 2, 2006 FTK Meeting 6

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…

May 2, 2006 FTK Meeting 7

LVL1 Jet Trigger Response (2)

10.3.0

11.0.41

J6 LVL1 jet trig resp

May 2, 2006 FTK Meeting 8

LVL1 Tau Trigger Response• Tau-trigger response fit in progress.

– Could LVL1 trig rate get sizeable contribution from real taus? If so, need parametrization.

ATLFASTjet pT (GeV)

cluster ET response

LVL1

t E

T (

GeV

)

ATLFASTjet pT (GeV)

May 2, 2006 FTK Meeting 9

Trigger Timing Issues• http://hepunx.rl.ac.uk/atlasuk/simulation/

level2/meetings/PESAlvl2IDswReview2005/TIMENOTE/l2time_note.pdf : LVL2 tracking timing note, summer 2005.

May 2, 2006 FTK Meeting 10

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…

May 2, 2006 FTK Meeting 11

Next steps• Physics case note started.

• Apply everything to Hhh4b channel.

• Improvements to sherpa samples and parametrizations if not too disruptive or time-consuming.

• Incoming UC grad student can work on VBF Hbb.

May 2, 2006 FTK Meeting 12

Reconstructed mh/H for bkgdNew large Sherpa sample w/ new LVL1 parametrization

  Start Trig B tags mh mH

# Events 1.08e+07 5307 0.0069 0.0053 0.00089

Cut eff.   0.0% 0.0% 77.4% 16.6%