ISSN - 03702693, Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 2002, vol. 546, p. 196-205
Measurement of CP-violating parameters in B → η′ K decays
We present measurements of CP-violating parameters in B0(B0) → η′ KS 0 and B± → η′ K± decays based on a 41.8 fb-1 data sample collected at the Υ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. We fully reconstruct one neutral B meson as a B0(B0) → η′ KS 0 CP eigenstate and identify the flavor of the accompanying B from its decay products. From the distribution of proper time intervals between pairs of B meson decay points, we obtain the CP-violating asymmetry parameters Sη′ KS 0 = 0.28 ± 0.55(stat)-0.08 +0.07(syst), and Aη′ KS 0 = 0.13 ± 0.32(stat)-0.06 +0.09(syst). We also reconstruct charged B± → η′ K± decays and determine a direct-CP-violating asymmetry value of Aη′ K± = (-1.5 ± 7.0(stat) ± 0.9(syst))%. © 2002 Elsevier Science B.V. All rights reserved.