Study of time-dependentCP-violating asymmetries inb→sq¯qdecays

We present a measurement of $\mathrm{CP}$-violation parameters in the $\overrightarrow{b}s\overline{q}q$ penguin transitions $\mathrm{}(q=s,u,d)\mathrm{}$ based on a $78{\mathrm{fb}}^{-1}$ data sample collected at the ${\rm Y}\mathrm{}\left(4S\right)\mathrm{}$ resonance with the Belle detector at the KEKB energy-asymmetric $e^{+}{e}^{-}$ collider. One neutral B meson is reconstructed in the $\phi K_S^0,$ $K^{+}{K}^{-}{K}_S^0,$ or ${\eta }^{\prime }{K}_S^0$ decay channel, and the flavor of the accompanying B meson is identified from its decay products. $\mathrm{CP}$ violation parameters for each of the three modes are obtained from the asymmetries in the distributions of the proper-time intervals between the two B decays.