Progress on FTK Studies FTK Physics Case Meeting 07/20/05 Erik Brubaker University of Chicago

July 20, 2005FTK Physics Case Meeting2 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 p T. Then all the various processes for physics studies can be studied using ATLFAST.

July 20, 2005FTK Physics Case Meeting3 Upgrade to —Why? Bug causing energy to disappear in L1 fixed. –Caused second band in response plot below. –Affected low-pt jets? Not clear… –L1 E T > 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, 2005FTK Physics Case Meeting4 Upgrade to —How? One of the first to use 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 COOL Otherwise ~50 simultaneous jobs overwhelm the ATLAS database server. –AtlfastAlgs Otherwise random crashes occur in Atlfast.

July 20, 2005FTK Physics Case Meeting5 Upgrade to —Results Second band gone from jet response plot: Interesting tau triggers to look at. J2 only J1-J8 ?

July 20, 2005FTK Physics Case Meeting6 Response parameterization—Old Problems with previous parameterization as shown last time by Catalin. –Discontinuities: Pathological behavior such as  Landau  0, etc. –Odd behavior at low p T, due to Landau.

July 20, 2005FTK Physics Case Meeting7 Response parameterization—New Improved functional form: tried & true double Gaussian. –No pathological behaviors –Second Gaussian can take care of high tails (?)

July 20, 2005FTK Physics Case Meeting8 Response parameterization—New Trigger turn-on curves vs “truth” from simulation. Still used in the same way as last time. Updated macro file to be sent after the mtg.

July 20, 2005FTK Physics Case Meeting9 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, 2005FTK Physics Case Meeting10 Double Higgs—Process Resonant production of lightest MSSM neutral scalar Higgs h 0 through the heavier H 0. Previous study (ATL-PHYS ) –For M H =300 GeV and tan(  =3, S/sqrt(B) of 5.7 can be reached using 300 fb -1 ; this requires 4 jets with E T >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, 2005FTK Physics Case Meeting11 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, 2005FTK Physics Case Meeting12 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 2  2 + 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, 2005FTK Physics Case Meeting13 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. SampleJ1J2J3J4 p T range N Events N Passed1e-93e Fraction7e-141.6e-81.5e-36e-2

July 20, 2005FTK Physics Case Meeting14 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.