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Paolo Massarotti K charged meeting 29 July 2004. Charged kaon lifetime. F. Ambrosino, P. De Simone, P. Massarotti, V. Patera. Measure ot T : length. •.
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Paolo Massarotti K charged meeting 29 July 2004 Charged kaon lifetime F. Ambrosino, P. De Simone, P. Massarotti, V. Patera.
Measure ot T: length • Paolo Massarotti K charged meeting 29 July 2004
Daughter P* with kaon mass hypothesis Background analisys • Four falimies: • good vertex (~ 69%) • kaon hits associated to daughter track (~ 20%) • Daughter hits associated to kaon track (~ 5%) • kaon broken track(~ 6%) Cut on 100 MeV Paolo Massarotti K charged meeting 29 July 2004
Measure of T on MC aG = (101.2 0.6) x10-2 bG = (.15 .27) x10-3 MC true MC reco T+true = 12.37 ns c2 = 1.3 c2 = 0.6 T+MC = (12.35±0.08) ns T-MC = (12.37±0.11) ns Paolo Massarotti K charged meeting 29 July 2004
We use neutral and charged vertex Measure of T: time g from p0 kaon Paolo Massarotti K charged meeting 29 July 2004
daughter kaon • g on time Paolo Massarotti K charged meeting 29 July 2004 Neutral vertex efficiency • we look for a vertex with: • 1 g on time • P* < 220 MeV
Paolo Massarotti K charged meeting 29 July 2004 Neutral vertex efficiency: MC true and reco aNV = (104.7 1.1) x10-2 bNV = (2.0 .43) x10-3 MC true MC reco
Paolo Massarotti K charged meeting 29 July 2004 g from p0 recostruction efficiency aNV = (96.15 .7) x10-2 bNV = (.33 .03) x10-3
Paolo Massarotti K charged meeting 29 July 2004 Contamination: d aNV = (1.7 0.3) x10-2 bNV = (.91 .11)x10-3 aNV = (2.6 0.3) x10-2 bNV = (.50 .12) x10-3 plus minus
Paolo Massarotti K charged meeting 29 July 2004 Neutral and charged vertex efficiency: MC true and reco aNV CV = (106.3 .2) x10-2 bNV CV= (1.8 .8) x10-3
Measure of T: MC T-MC = (12.38 ± 0.02) ns T+MC = (12.35 ± 0.04) ns Paolo Massarotti K charged meeting 29 July 2004
Paolo Massarotti K charged meeting 29 July 2004 Conclusions • Two different methods to measure charged kaon lifetime have been implemented • The studies on systematics must be performed on a larger sample of data • Data have to be analyzed