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This talk discusses the performance of the detector and physics aspects related to muon identification and reconstruction in the ATLAS experiment. It covers various topics including track matching, pattern recognition, muon spectrometer standalone, and muon performance from data.
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Detector Performance and Physics talks at Bern (very selective!) Pete Watkins
Combined Muon Rec. and Redundancy • I Match tracks from Inner Detector (ID) and Muon Spectrometer (MS) • combine ID and Muon parameters: STACO • fit ID+Muon track, use Calo energy loss:MuId and other modular approaches • II Tag ID tracks with MS segments • match ID track with unassociated or any segment: Mutag, MutagIMO • III Pattern recognition outside ID • E deposits and ID track: CaloTag, CaloLR • seed MS pattern recog. with ID track: MuGirl • IV MuonSpectrometer standalone • full reco chain: MoMuMoore and Muonboy Precisely measure high-pT muons High and robust muon efficiency Low-pT muons, regions with little instrumentation Beyond ID acceptance ||>2.5
Muon Performance from Data • a variety of principles studied to measure efficiency and fake rates from data, as input to physics analyses and MC modelling - see for example CSC note “In-Situ determination of the performance…” • Analyses generally exploit the measurement of µ pairs from J/, or Z decays by more than one detector (redundancy) - tag-and-probe method - (1) tagged combined muon - (2) probe muon from ID track and invariant mass selection • Current activities: • efficiency meas’t, achieve eff<1% • J/ in low-pT region, requiring control of bbXµ(6) background - sig/bg recently improved from 2:1 to ~100:1 by Tile match and IP cuts • fake rate measurement from known non-µ decays, like Ks->π+π- • study fake high momentum of real muons (Z->µµ, sev. 100 GeV) • And: pT resolution, energy scale, muon energy loss in Calo
EtMiss performance Linearity Resolution Angular Resolution From Donatella’s presentation at June Workshop
Standard Performance Plots From k.lohwasser1@physics.ox.ac.uk Wed Jul 2 05:47:10 2008 Date: Wed, 2 Jul 2008 12:47:07 +0200 There is a plan to compile an Athena package, which accommodates various in-situ and MC methods to evaluate Jet Performances. The advantages would be, that various methods/datasets/JetAlgorithms could be compared in a fast and consistent way. The package as implemented so far can run on AOD (using the grid or local batch),delivering ROOT.histogramm output. What would still be needed would be people willing to contribute to the package (some having already expressed interest). A general description with links to slides and doxygen of the latest version can be found here: https://twiki.cern.ch/twiki/bin/view/Atlas/JetPerformancePackage Please let me know any suggestions, ideas, ... People Wanted ! Another advantage is that these might be straightforward to approve for public presentation
EtMiss in Early data • Instrumental effects have be understood first!! EtMiss is sensitive to each instrumental effect (cosmics, beam gas, beam halo, dead/hot/noisy cells/regions…. • Use SM events to validate EtMiss *minimum bias * W ln * Z tt * Z ll * tt • Determine the absolute scale in-situ • Check the resolution Z tt In 100pb-1 expect: ~ 7000 (250 after cuts to suppress backgrounds) Z lepton-hadron with pTe or pTm> 15GeV From Donatella’s Presentation at June Workshop