Progress on FTK Studies FTK Physics Case Meeting 07/20/05 Erik Brubaker University of Chicago.
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Transcript of Progress on FTK Studies FTK Physics Case Meeting 07/20/05 Erik Brubaker University of Chicago.
July 20, 2005 FTK Physics Case Meeting 2
Reminder: Purpose• Making the physics case for FTK means studying
signal and background trigger rates for several processes.
• ATLAS full simulation is very slow.
• Solution: use fully simulated events to parameterize the L1 jet and tau trigger response vs ATLFAST jet pT. Then all the various processes for physics studies can be studied using ATLFAST.
July 20, 2005 FTK Physics Case Meeting 3
Upgrade to 10.3.0—Why?• Bug causing energy to disappear in L1 fixed.
– Caused second band in response plot below.– Affected low-pt jets? Not clear…
– L1 ET > 1 TeV also a bug, not fixed yet, but minor effect.
• Rerun jobs anyway to loosen thresholds on jet, tau triggers.– Allow parameterization of
response w/o arbitrary cutoff.– Allow investigation of tau
trigger iso cuts.
July 20, 2005 FTK Physics Case Meeting 4
Upgrade to 10.3.0—How?• One of the first to use 10.3.0 for running many
jobs in parallel.• This is not necessarily a good idea… ATLAS
software releases X.Y.Z with Y=0 are production releases. With Y>0 are development releases.
• Besides patches found on the TWiki, I needed– IOVDbSvc-00-02-18-COOL-1-1-0
• Otherwise ~50 simultaneous jobs overwhelm the ATLAS database server.
– AtlfastAlgs-00-01-84• Otherwise random crashes occur in Atlfast.
July 20, 2005 FTK Physics Case Meeting 5
Upgrade to 10.3.0—Results• Second band gone
from jet response plot:
• Interesting tau triggers to look at.
J2 only J1-J8
?
July 20, 2005 FTK Physics Case Meeting 6
Response parameterization—Old• Problems with previous parameterization as
shown last time by Catalin.– Discontinuities: Pathological behavior such as
Landau0, etc.
– Odd behavior atlow pT, due toLandau.
July 20, 2005 FTK Physics Case Meeting 7
Response parameterization—New• Improved
functional form: tried & true double Gaussian.– No pathological
behaviors– Second Gaussian
can take care of high tails (?)
July 20, 2005 FTK Physics Case Meeting 8
Response parameterization—New• Trigger turn-on curves vs “truth” from
simulation.
Still used inthe same wayas last time.
Updated macrofile to be sentafter the mtg.
July 20, 2005 FTK Physics Case Meeting 9
Response parameterization—taus• Tau energy response
not as Gaussian as jets.– Not a surprise
• Need to decide how to treat iso cut!– Given iso cuts,
parameterize energy response.
– Or parameterize also iso response (harder).
– Need to study iso cuts for tau triggers?
July 20, 2005 FTK Physics Case Meeting 10
Double Higgs—Process• Resonant production of
lightest MSSM neutral scalar Higgs h0 through the heavier H0.
• Previous study (ATL-PHYS-97-104)– For MH=300 GeV and tan(=3, S/sqrt(B) of 5.7 can
be reached using 300 fb-1; this requires 4 jets with ET>40 GeV and ||<2.5.
– For lower integrated luminosity, more tricks are needed and jets down to 20 GeV are preferred.
– They concluded trigger rates probably prohibitive.
July 20, 2005 FTK Physics Case Meeting 11
Double Higgs—Signal MC• Initial intel was that double Higgs production not
implemented in Pythia.– Seems to be generally true, but this specific process is
available. Developing…
• Instructions available for modifying Pythia to include the relevant MSSM Higgs processes, if needed.– Claim is that it’s very complicated avoid if
possible!
July 20, 2005 FTK Physics Case Meeting 12
Double Higgs—Background MC• RomeBackgroundWiki: Multijet sample for
Rome production cancelled due to “insufficient resources”.
• Trying to find out details of what was planned, will produce this at UChicago Tier2.– ME for 3- or 4-jet production?– Or just Pythia 22 + parton shower with generator
cuts to ensure additional hard partons?– This will be a useful sample to have available!
• For now, look at dijet samples…
July 20, 2005 FTK Physics Case Meeting 13
Double Higgs—Background rates• Use J1-J8 dijet samples.• Require at least 4 ATLFAST jets inside ||<2.8.• Find the probability for the event to have four jets
passing a 40 GeV trigger.
Sample J1 J2 J3 J4
pT range 17-35 35-70 70-140 140-280
N Events 16527 19851 19807 892
N Passed 1e-9 3e-4 30.2 49.4
Fraction 7e-14 1.6e-8 1.5e-3 6e-2
July 20, 2005 FTK Physics Case Meeting 14
Future plans• Keep up with improvements in L1 trigger
simulation as needed (nothing now).
• Improve parameterizations as needed.– Regions where tails must be well described.– Tau param. w/ different iso cuts? As function of iso?– Event pass function.
• Get real signal, bkgd MC for double Higgs, continue study.
• Expand into other processes as appropriate.