Differential branching fraction and angular analysis of the decay $B_s^0\to\phi\mu^{+}\mu^{-}$

TL;DR

This paper reports the first measurement of the differential branching fraction and angular observables of the decay $B_s^0\to\phi\mu^{+}\mu^{-}$ using LHCb data, finding results consistent with the Standard Model.

Contribution

The study provides the first angular analysis of the decay $B_s^0\to\phi\mu^{+}\mu^{-}$ and measures its differential branching fraction across $q^2$ bins.

Findings

Total branching fraction measured as (7.07^{+0.64}_{-0.59}±0.17±0.71)×10^{-7}

Angular observables $F_L$, $S_3$, $A_6$, $A_9$ are consistent with Standard Model

First angular analysis of this decay mode

Abstract

The determination of the differential branching fraction and the first angular analysis of the decay $B_s^0\to\phi\mu^{+}\mu^{-}$ are presented using data, corresponding to an integrated luminosity of $1.0\,{\rm fb}^{-1}$, collected by the LHCb experiment at $\sqrt{s}=7\,{\rm TeV}$. The differential branching fraction is determined in bins of $q^{2}$, the invariant dimuon mass squared. Integration over the full $q^{2}$ range yields a total branching fraction of ${\cal B}(B_s^0\to\phi\mu^{+}\mu^{-}) = (7.07\,^{+0.64}_{-0.59}\pm 0.17 \pm 0.71)\times 10^{-7}$, where the first uncertainty is statistical, the second systematic, and the third originates from the branching fraction of the normalisation channel. An angular analysis is performed to determine the angular observables $F_{\rm L}$, $S_3$, $A_6$, and $A_9$. The observables are consistent with Standard Model expectations.