Study of CP asymmetry in B0-B0bar mixing with inclusive dilepton events

Abstract

We present a measurement of the asymmetry $A_{CP}$ between same-sign inclusive dilepton samples ${\ell }^{+}{\ell }^{+}$ and ${\ell }^{-}{\ell }^{-}$ ($\ell =e,\hat{I}¼$) from semileptonic B decays in Y(4S) --> BBbar events, using the complete data set recorded by the BABAR experiment near the Y(4S) resonance, corresponding to 471 million BBbar pairs. The asymmetry A_{CP} allows comparison between the mixing probabilities P(B0bar --> B0) and P(B0 --> B0bar), and therefore probes CP and T violation. The result, $A_{CP}=(-3.9\pm 3.5(stat)\pm 1.9(syst))\times 10^{-3}$, is consistent with the Standard Model expectation.

7 pages, 3 figures, submitted to Phys. Rev. Lett