Some D0 Meeting December 2003 Muon Isolation Update Ken Johns University of Arizona

Some D0 Meeting December 2003 Conclusions  p13 vs p14 (not42) u ~2x events in p14 u Halo11 efficiency improves (70% vs 55%) u Little effect on Trkpt and Rat efficiency  p14 (t42) vs p14 (not42) u 25% less events u Halo11 and Rat efficiency unchanged (70%) u Trkpt efficiency improves?? (75% vs 55%)  Background efficiency u 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 Meeting December 2003 Conclusions  Rat = Halo11 / Ptmu u Let Ptmu = 6, 10, 12, 15 GeV/c u 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 u => Slowly varying with Ptcut u => But other variables change with Ptmu cut as well (statistics?)  Signal efficiency for 10% background efficiency u Use 12 GeV/c cut sample for all background variables u For comparison, set background efficiency to 10%  Halo11 efficiency for signal = 75%  Trkpt efficiency for signal = 50%  Rat efficiency for signal = 92%  dR efficiency for signal = 75%

Some D0 Meeting December 2003 Z, Zj, Zjj Data  Sample u Emily Z skim u Cuts  Good vertex  2 muons with P T > 15 GeV/c  1 isolated muon  Same vertex  Muon phi (highest P T ) – metphi < 165 degrees  Corrected MET < 15 GeV  75 < dimu mass < 105 GeV/c 2  0, 1, >1 jets with E T > 20 GeV u Look at distributions of the “other” muon

Some D0 Meeting December 2003 Halo 11 (p13 vs p14-not42)

Some D0 Meeting December 2003 Trkpt (p13 vs p14-not42)

Some D0 Meeting December 2003 Rat (p13 vs p14-not42)

Some D0 Meeting December 2003 Halo11 p14 (not42 vs t42)

Some D0 Meeting December 2003 Trkpt p14 (not42 vs t42)

Some D0 Meeting December 2003 Rat p14 (not42 vs t42)

Some D0 Meeting December 2003 bb p13 Data  Sample u Dimu p13 skim u Cuts  Good vertex  2 muons with P T > 6 GeV/c  // ΔR > 0.5 between the two muons  1 muon with an associated jet  Same vertex  Muon phi (highest P T ) – metphi < 165 degrees  Corrected MET < 15 GeV  0 < dimu mass < 70 GeV/c 2  >1 jets with E T > 20 GeV u Look at distributions of the “other” muon

Some D0 Meeting December 2003 Halo11 (Zjj vs bb)

Some D0 Meeting December 2003 Trkpt (Zjj vs bb)

Some D0 Meeting December 2003 Rat (Zjj vs bb)

Some D0 Meeting December 2003 dr (Zjj vs bb)

Some D0 Meeting December 2003 Next Steps  With signal and background efficiencies we can proceed to the using the matrix method u tt to mumu cuts with no H T cut and MET > 20 GeV cut u Like sign and unlike sign  Develop muon isolation likelihood  Cross-check bb distributions using single muon sample