Skeleton outline for the physics case document M. Shochet December 15, 2005

Physics Case for the FTK Fast Track Finder I.Introduction The general argument: unknown new physics  best toolbox Importance of the 3 rd generation to new physics: EWK symmetry breaking, SUSY, … Challenge of efficiency, rapid identification of b and  jets in the trigger because of large backgrounds oEarly access to high quality tracks can give rapid rejection in L2  lower deadtime  can reduce the L1 threshold to increase physics efficiency Rapid tracking can be useful for many purposes including calibration: ex, single isolated track trigger for calorimeter calibration (low P T & W→  ) Here we focus on 3 rd generation partons Remaining sections:

–b-jet ID –  -jet ID (1 & 3 prong) –Z→bb –bbH/A→ 4 b’s (& 2 b’s 2  ’s ?) –VBF production of H→  –H→hh→4b’s –B s →  –(generic l  triggers ?) –Summary & conclusions * As we go, we have to keep tabs on the total requested additional L1 jet trigger rate (use common thresholds when possible).

II.The CDF Experience ex: early predicted trigger rates vs. reality; SVT success – B physics expectation before run I vs. what was done (SVT needed for unanticipated physics); Z  bb – bb purity after trigger III.Overview of FTK (technical details elsewhere) IV.Rapid selection of b-jets Simulation samples used Optimization procedure b-jet efficiency vs light quark & gluon rejection factor Comparison with planned trigger and offline algorithms IV.Rapid selection of  jets Same bullets as in III with addition of –Triggering on 3-prong  decay (for polarization information) V.Z→bb Measure b-jet response of ATLAS calorimeter, check the shift when b semileptonic decay is identified, additional check of overall ATLAS jet energy scale Problem: maintaining low enough L1 rate and having low M JJ turn- on to get background shape

Solution: high P T Z’s (3-jet trigger) Background & signal after trigger Z mass uncertainty & width vs. integrated luminosity VI.bbH/A→4 b’s pick a few points in parameter space (just) outside ATLAS sensitivity region Signal & background samples used (describe use of ATLFast and use of transfer functions) Background rate & signal efficiency vs selection criteria Observation significance vs integrated luminosity & comparison to ATLAS baseline result VII.VBF production of H  Same as above, with discussion of forward jets &/or rapidity gaps.