出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：We report an improved measurements of direct CP violation in the decay B0 !K+p using 350
fb1 of data and measurements of B meson decays to two kaons using 253 fb1 of data. The
measured CP violating asymmetries are ACP(K+p) = 0:113 0:022(stat:) 0:008(syst:),
ACP(K+p0)=0:040:04(stat:)0:02(syst:) andACP(p+p0)=0:020:08(stat:)0:01(syst:),
where the latter correspond to the intervals 0:03 < ACP(K+p0) < 0:11 and 0:12 <
ACP(p+p0) < 0:15 at 90% condence level. We also nd evidence for signals in B+ ! K0K+
and B0 ! K0K0 with signicances of 3:0s and 3:5s , respectively. (Charge-conjugate modes
included) The corresponding branching fractions are measured to be B(B+ !K0K+) = (1:0
0:40:1)106 and B(B0 !K0K0
) = (0:80:30:1)106. No signal is observed in the
decay B0!K+K and we set an upper limit of 3:7107 at 90% condence level. These results
are obtained from a data sample collected near the ¡(4S) resonance, with the Belle detector at the
KEKB asymmetric energy e+e collider.
