Measurement of $CP$ asymmetries in the decays $B^0\to K^{\ast 0}\hat{I}{¼}^{+}\hat{I}{¼}^{-}$ and $B^{+}\to K^{+}\hat{I}{¼}^{+}\hat{I}{¼}^{-}$

Abstract

The direct $CP$ asymmetries of the decays $B^0\to K^{\ast 0}\hat{I}{¼}^{+}\hat{I}{¼}^{-}$ and $B^{+}\to K^{+}\hat{I}{¼}^{+}\hat{I}{¼}^{-}$ are measured using $pp$ collision data corresponding to an integrated luminosity of 3.0$\mbox{fb}^{-1}$ collected with the LHCb detector. The respective control modes $B^0\to J/\ddot{I}ˆK^{\ast 0}$ and $B^{+}\to J/\ddot{I}ˆK^{+}$ are used to account for detection and production asymmetries. The measurements are made in several intervals of $\hat{I}{¼}^{+}\hat{I}{¼}^{-}$ invariant mass squared, with the $\ddot{I}•(1020)$ and charmonium resonance regions excluded. Under the hypothesis of zero $CP$ asymmetry in the control modes, the average values of the asymmetries are \begin{align} {\cal A}_{C\!P}(B^0 \rightarrow K^{*0} μ^+ μ^-) &= -0.035 \pm 0.024 \pm 0.003, \cr {\cal A}_{C\!P}(B^+ \rightarrow K^{+} μ^+ μ^-) &= \phantom{-}0.012 \pm 0.017 \pm 0.001, \end{align} where the first uncertainties are statistical and the second are due to systematic effects. Both measurements are consistent with the Standard Model prediction of small $CP$ asymmetry in these decays.

19 pages including author list, 4 figures