Measurement of form-factor independent observables in the decay $B^{0} \to K^{*0} \mu^+ \mu^-$

TL;DR

This paper reports measurements of angular observables in the decay B0 to K*0 mu+ mu-, testing Standard Model predictions and finding one significant local discrepancy in a specific q^2 bin.

Contribution

First measurement of form-factor independent angular observables in B0 to K*0 mu+ mu- decay using LHCb data at 7 TeV.

Findings

23 out of 24 measurements agree with Standard Model

A 3.7 sigma local discrepancy in one q^2 bin

Probability of such a discrepancy occurring by chance is 0.5%

Abstract

We present a measurement of form-factor independent angular observables in the decay \mbox{$B^0\to K^{*}(892)^{0}\mu^+ \mu^-$}. 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 $0.5\%$.