Some D0 MeetingDecember 2003

Muon Isolation Update

Ken JohnsUniversity of Arizona

Some D0 MeetingDecember 2003

Conclusions

p13 vs p14 (not42) ~2x events in p14 Halo11 efficiency improves (70% vs 55%) Little effect on Trkpt and Rat efficiency

p14 (t42) vs p14 (not42) 25% less events Halo11 and Rat efficiency unchanged (70%) Trkpt efficiency improves?? (75% vs 55%)

Background efficiency For comparison, set background efficiency to 10%

Halo11 efficiency for signal = 55% Trkpt efficiency for signal = 38% Rat efficiency for signal = 92% dR efficiency for signal = 50%

Some D0 MeetingDecember 2003

Conclusions

Rat = Halo11 / Ptmu Let Ptmu = 6, 10, 12, 15 GeV/c Find Rat cut where background efficiency = 10%

6 GeV/c = 0.32 10 GeV/c = 0.30 12 GeV/c = 0.28 15 GeV/c = 0.25

=> Slowly varying with Ptcut => But other variables change with Ptmu cut as well

(statistics?) Signal efficiency for 10% background efficiency

Use 12 GeV/c cut sample for all background variables For comparison, set background efficiency to 10%

Halo11 efficiency for signal (@3.8) = 75% Trkpt efficiency for signal (@2.0) = 50% Rat efficiency for signal (@0.28) = 92% dR efficiency for signal (@0.5) = 75%

Some D0 MeetingDecember 2003

Z, Zj, Zjj Data

Sample Emily Z skim Cuts

Good vertex 2 muons with PT > 15 GeV/c 1 isolated muon Same vertex Muon phi (highest PT) – metphi < 165

degrees Corrected MET < 15 GeV 75 < dimu mass < 105 GeV/c2

0, 1, >1 jets with ET > 20 GeV Look at distributions of the “other” muon

Some D0 MeetingDecember 2003

Halo 11 (p13 vs p14-not42)

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Trkpt (p13 vs p14-not42)

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Rat (p13 vs p14-not42)

Some D0 MeetingDecember 2003

Halo11 p14 (not42 vs t42)

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Trkpt p14 (not42 vs t42)

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Rat p14 (not42 vs t42)

Some D0 MeetingDecember 2003

bb p13 Data

Sample Dimu p13 skim Cuts

Good vertex 2 muons with PT > 6 GeV/c // ΔR > 0.5 between the two muons 1 muon with an associated jet Same vertex Muon phi (highest PT) – metphi < 165 degrees Corrected MET < 15 GeV 0 < dimu mass < 70 GeV/c2

>1 jets with ET > 20 GeV Look at distributions of the “other” muon

Some D0 MeetingDecember 2003

Halo11 (Zjj vs bb)

Some D0 MeetingDecember 2003

Trkpt (Zjj vs bb)

Some D0 MeetingDecember 2003

Rat (Zjj vs bb)

Some D0 MeetingDecember 2003

dr (Zjj vs bb)

Some D0 MeetingDecember 2003

Next Steps

With signal and background efficiencies we can proceed to the using the matrix method tt to mumu cuts with no HT cut and MET >

20 GeV cut Like sign and unlike sign

Develop muon isolation likelihood Cross-check bb distributions using

single muon sample