Differential branching fraction and angular analysis of the decay $B^0\to K^{\ast 0}\hat{I}{¼}^{+}\hat{I}{¼}^{-}$

Abstract

The angular distribution and differential branching fraction of the decay $B^0\to K^{\ast 0}\hat{I}{¼}^{+}\hat{I}{¼}^{-}$ are studied using a data sample, collected by the LHCb experiment in $pp$ collisions at $\sqrt{s}=7\mathrm{TeV}$, corresponding to an integrated luminosity of $1.0{\mathrm{fb}}^{-1}$. Several angular observables are measured in bins of the dimuon invariant mass squared, $q^2$. A first measurement of the zero-crossing point of the forward-backward asymmetry of the dimuon system is also presented. The zero-crossing point is measured to be $q_0^2=4.9\pm 0.9{\mathrm{GeV}}^2/c^4$, where the uncertainty is the sum of statistical and systematic uncertainties. The results are consistent with the Standard Model predictions.