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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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

5

data with PCORMC standard

+ve

-ve

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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Bhabha selection 1Barrel

11/12/2002 Lepton momentum- Andrea Venturi - W meeting

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Bhabha selection 2Barrel

11/12/2002 Lepton momentum- Andrea Venturi - W meeting

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Bhabha selection 3Barrel

11/12/2002 Lepton momentum- Andrea Venturi - W meeting

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Bhabha selection 4Barrel

11/12/2002 Lepton momentum- Andrea Venturi - W meeting

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Di-muon s selection 1Barrel

11/12/2002 Lepton momentum- Andrea Venturi - W meeting

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Di-muon s selection 2Barrel

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