Presentation on theme: "K fake rates from D ⁰ →K - + Vs D ⁰ →K ± ∓ Sadia Khalil & Sheldon Stone EHEP Group Meeting Oct 2007."— Presentation transcript:
K fake rates from D ⁰ →K - + Vs D ⁰ →K ± ∓ Sadia Khalil & Sheldon Stone EHEP Group Meeting Oct 2007
Objective Study the RICH efficiency and fake rates for kaons and pions. Method D 0 D 0 → K - +, K ± (CC is implied) Selection Criteria TagSide Signal Side < E 1 < < E 2 <
Kaon with RICH
Pion with RICH
To ascertain the backgrounds we checked m bc (Kpi) Vs m bc (Kpi) plot The signal side is described with the RICH applied.
No PIDSingle K Single Double ID K - +, K ± RSWSRSWSRSWSRSWS Result(600pb -1 ) The 2 events in WS-Double ID can be only from mixing as doubly Cabbibo decays are forbidden due to Bose-Einsitien statistics or they can be background. We subtract these 2 (actually RS) events from the other WS candidates. Efficiencies and Fake Rates ε K = 90.6 %, ε = 97.4 % f K→ = (2.41± 0.52) % f →K = (1.08± 0.34) %