cross-check of lepton track momentum
DESCRIPTION
Cross-check of lepton track momentum. Andrea Venturi. Renaud’s results. About 100-170 MeV discrepancy in electron TPC momentum observed in Z Bhabha events (1998) Cross-check with my ntuples used for track distortion measurements and with di-muon events. Event selection and reconstruction. - PowerPoint PPT PresentationTRANSCRIPT
11/12/2002 Lepton momentum- Andrea Venturi - W meeting
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Cross-check of lepton track momentum
Andrea Venturi
11/12/2002 Lepton momentum- Andrea Venturi - W meeting
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Renaud’s results
• About 100-170 MeV discrepancy in electron TPC momentum observed in Z Bhabha events (1998)
• Cross-check with my ntuples used for track distortion measurements and with di-muon events
11/12/2002 Lepton momentum- Andrea Venturi - W meeting
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Event selection and reconstruction
• Preselection:– 2-6 good charged tracks– two leading tracks with |cos|<0.95
• Bhabha selection: 4 selections1. E(ecal)/P > 0.7 for at least one track2. E(ecal)/Ebeam > 0.7 for both tracks3. as 2. + P/Ebeam > 0.4 for both tracks4. “Renaud’s selection”:
• P1+P2 > 0.2*sqrt(s)• E(ecal)1+E(ecal)2> 0,45*sqrt(s)• sum(E(ecal)+E(hcal)+P) > 1.4*sqrt(s)• |cos *|<0.9
• Di-muon selection: 2 selections1. mu-id or ECAL mips for both tracks2. as 1. + P/Ebeam > 0.7 for both tracks
• No background (so far)• Sagitta correction applied to data and no
change to MC– sagitta corrections and distortion simulation are
relevant only if charge is looked at.
11/12/2002 Lepton momentum- Andrea Venturi - W meeting
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data no PCORMC with distortionsMC std
+ve
-ve
11/12/2002 Lepton momentum- Andrea Venturi - W meeting
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data with PCORMC with distortions and PCORMC std
+ve
-ve
11/12/2002 Lepton momentum- Andrea Venturi - W meeting
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To be investigated
• Dependence on the selection– background– correlations among sub-detectors
• Tails– lower tail
• background
– upper tail• resolution: 1/p is gaussian non-linearity
• Fit distribution peak– resume already existing results
• Polar angle biases pz
• B field ?
• Aim to simulate the effect for systematic studies