Measurement of form-factor independent observables in the decay $B^0\to K^{\ast 0}\hat{I}{¼}^{+}\hat{I}{¼}^{-}$

Abstract

We present a measurement of form-factor independent angular observables in the decay \mbox{$B^0\to K^{\ast }(892{)}^0\hat{I}{¼}^{+}\hat{I}{¼}^{-}$}. The analysis is based on a data sample corresponding to an integrated luminosity of 1.0fb${}^{-1}$, collected by the LHCb experiment in $pp$ collisions at a center-of-mass energy of 7TeV. Four observables are measured in six bins of the dimuon invariant mass squared, $q^2$, in the range $0.1<q^2<19.0$GeV${}^2$/c${}^4$. Agreement with Standard Model predictions is found for 23 of the 24 measurements. A local discrepancy, corresponding to $3.7$ Gaussian standard deviations, is observed in one $q^2$ bin for one of the observables. Considering the 24 measurements as independent, the probability to observe such a discrepancy, or larger, in one is $0.5\%$.