ISSN - 15507998, Physical Review D - Particles, Fields, Gravitation and Cosmology, 2003, vol. 68, p. 111031-111036
Improved measurement of the partial-rate CP asymmetry in B +→K0π+ and B -→K̄0π- decays
We report an improved measurement of the partial-rate CP asymmetry in B±→K(-)0π± decays. The analysis is based on a data sample of 85×106 BB̄ pairs collected at the Γ(4S) resonance with the Belle detector at the KEKB e+e- storage ring. We measure A CP((K(-)0π± = 0.07 -0.08 -0.03 +0.09 +0.01, where the first and second errors are statistical and systematic, respectively; the corresponding 90% confidence-level interval is -0.10 <ACP(K(-) 0π±)<0.22.