We report a measurement of CP violating asymmetries in B0(B0)→K+K−KS0 decays with a time-dependent Dalitz approach. This analysis
is based on a data sample of 657×106BB pairs accumulated
at the Υ(4S) resonance with the Belle detector at the KEKB
asymmetric-energy e+e− collider. As the result of an unbinned maximum
likelihood fit to the selected candidates, the mixing-induced and direct CP
violation parameters, ϕ1eff and ACP are obtained for
B0→ϕ(1020)KS0, B0→f0(980)KS0 and other B0→K+K−KS0 decays. We find four solutions that describe the data. There are
\{eqnarray*} \phi_1^{\rm eff}(B^0\to \phi(1020) K^0_S) & = & (32.2 \pm 9.0 \pm
2.6 \pm 1.4)^{\circ}; \phi_1^{\rm eff}(B^0\to \phi(1020) K^0_S) & = & (26.2 \pm
8.8 \pm 2.7 \pm 1.2)^{\circ};\\ \phi_1^{\rm eff}(B^0\to \phi(1020) K^0_S) & = &
(27.3 \pm 8.6 \pm 2.8 \pm 1.3)^{\circ}\; {\rm and}\\ \phi_1^{\rm eff}(B^0\to
\phi(1020) K^0_S) & = & (24.3 \pm 8.0 \pm 2.9 \pm 5.2)^{\circ}.{eqnarray*}\ The
values for the CP violating phase in B0→ϕ(1020)KS0 are similar
but other properties of the Dalitz plot are quite different for the four
solutions. These four solutions have consistent ϕ1eff values for
all three B meson decay channels and none of them deviates significantly from
the values measured in B→(ccˉ)K0 decays with the currently
available statistics. In addition, we find no significant direct CP
violation.Comment: submitted to PR