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InDet Tracking Performance. Stephen Haywood RAL. Overview. Introduction Performance presented in the ATLAS Detector Paper First Data. Introduction. Inner Detector Tracking Performance: Understand , Monitor and Optimise the ID performance .
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InDet TrackingPerformance Stephen Haywood RAL
Overview • Introduction • Performance presented in the ATLAS Detector Paper • First Data InDet Tracking Performance 2
Introduction • Inner Detector Tracking Performance: • Understand, • Monitor and • OptimisetheID performance. • Inner Detector Tracking Performance is a "forum" for bringing together various groups: • ID Software • Physics and Combined Performance Working Groups • Validation, ID Alignment and Calibration, Data Prep, etc • See TWiki: InDetTrackingPerformance • Group started work in Sep 07 … but dominated by Detector Paper. InDet Tracking Performance 3
Relationships Validation Software Data Prep Physics Commissioning Tracking Performance Data Quality Align activity Hardware Trigger working group InDet Tracking Performance 4
Detector Hardware & its expected Performance. Eva Bouhova Markus Elsing Daniel Froidevaux Grant Gorfine Stephen Haywood Vato Kartvelishvili Thomas Koffas Jason Lee Michael Leyton Giacinto Piacquadio Troels Petersen Darren Price Christoph Ruwiedel Andi Salzberger Laurent Vacavant Jean-Baptiste de Vivie Seth Zenz Hongbo Zhu Detector Paper InDet Tracking Performance 5
pT Resolution • s(pT) = s() (1 pMS/pT) • MS significant up to 40-80 GeV • High-pT resolution degraded by lack of TRT C-Wheels • Improvement compared to TDR due to • Use of Pixel ToT • Reduced TRT jitter InDet Tracking Performance 6
Impact Parameter Resolutions InDet Tracking Performance 7
Summary of Resolutions • In the Barrel region: 1/pT: s = 0.34×10-3 (1 44/pT) GeV-1 d0: s = 10 (1 14/pT) mm z0: s = 90 (1 2.3/pT) mm f: s = 70 (1 39/pT) mrad cotq: s = 0.7×10-3 (1 5/pT) GeV-1 • So for a 1 TeV muon, pT resolution is 34%. InDet Tracking Performance 8
Charge-sign Misidentification • Right: pT = 2 TeV • Sign identification important for high-pT electrons (muons measured by MuSpect) • Electrons suffer from confusion caused by brem and subsequent conversions • When resolution very poor (high pT and high |h|), brem reduces pT improving sign identification InDet Tracking Performance 9
Reconstruction Efficiency • Left: pT= 5 GeV Right: Pions • See effect of material • Efficiencies O(85)% for medium energy electrons & pions InDet Tracking Performance 10
Efficiency in Jets • Left: • Efficiency for: Reconstruction, Standard Cuts, b-tagging Cuts • Fake Rate for: Standard Cuts, b-tagging Cuts • Right: • Efficiency & Fake Rate for: ET < 50 GeV, ET > 100 GeV • See effect of material • See effect of PR confusion in jet core InDet Tracking Performance 11
Primary Vertex Resolution • With no beam-constraint: • t-tbar:sx,y = 18 mm sz = 41 mm • Hgg:sx,y = 36 mm sz = 72 mm • Reconstruct PV with 100% (96%) eff for t-tbar (Hgg) • Identify PV at 1033 cm-2s-1with 99% (79%) eff for t-tbar (Hgg) InDet Tracking Performance 12
Secondary Vertex Resolution • Left: tau decays Right: J/y decays • Tau decays are more collimated; gives rise to non-Gaussian distributions InDet Tracking Performance 13
K0s Reconstruction • Studied with VKalVrt & V0Fitter (and initially with CTVMFT) • Radial resolution sensitive to silicon layers InDet Tracking Performance 14
Material Effects • Left: Electrons Right: Photons • Geometry: • CSC-01 – used for Detector Paper studies • CSC-02 – includes improved estimates for services inside Tracking Volumes • CSC-03 – includes improved estimates for services outside Tracking Volumes • Detector Paper includes X0 plots made with CSC-03 InDet Tracking Performance 15
Bremsstrahlung Recovery • Left: pT = 25 GeV, End-caps Right: J/yee • Without additional info (eg Calo Cluster), it is difficult to improve measurements – information has been lost ! • Investigate how to apply Brem Rec depending on hypothesis (fit, TR) for particle InDet Tracking Performance 16
Conversion Recovery • Benefit from identification of single-track conversions in TRT • To be tested with real events: what is fake rate of conversions? InDet Tracking Performance 17
TRT TR Performance • Improved determination of TR threshold function from CTB • Pion Rejections between 10 and 100 are expected • The performance has degraded since the TDR’s InDet Tracking Performance 18
First Data • Organisation to be understood … at Ringberg Workshop 14-18 Apr. • Data Quality = Commissioning Team. • Strong connection with Alignment Team. • Will discuss and receive input from Beate Heinemann (CDF) at next InDet TrackPerf Meeting on 17 Jan. • Where possible, need to establish performance from Data, rather than MC. InDet Tracking Performance 19
Efficiencies • Min Bias – low pT • PR in Jets • HLT … for Trigger Community • Look at electrons identified in Calo, esp Wen, Zee • Look at muons identified in MuSpect, esp Wmn, Zmm • Look at taus in Ztt • … Oxford work from Maria & Guillaume – see Helen’s talk • Conversions: x-check single tracks conversions with reconstructed pairs InDet Tracking Performance 20
Resolutions • Look at pulls for hit residuals confirmation of hit errors nominal track resolutions (bar systematics, such as global distortions) • d0 & z0 from PV reconstruction • J/ymm & Zmm to confirm pT resolution • Strong overlap with Alignment & Calibration, since some of these distributions will be used to determine constants/corrections. InDet Tracking Performance 21
Alignment • Right: • Difference in pT spectra between m+ and m- – sensitive to global distortions (eg sagitta effects) • Huge effort, in particular in UK • With unaligned detector (build precision), Z mm peak is completely washed out InDet Tracking Performance 22
Alignment & Calibration • Alignment will have significant effect on: • PR in Jets • Vertexing • pT Resolution • Alignment – need Level-1 (ECA-B-ECC) alignment asap (Cosmics, beam-gas) • B-field – start with measured Solenoidal field • Material – start with estimated material; study in collaboration with e/g WG • Brem • Conversions • V0’s – energy loss InDet Tracking Performance 23
Conclusions • Post Detector Paper: CSC Note & Back-up Notes • Understand relationships with Commissioning & Alignment Teams • Get ready to look at First Data InDet Tracking Performance 24