$B_{d} -> K^{*} mu mu$ with ATLAS

A measurement of the forward-backward asymmetry $A_{FB}$ and the fraction of the longitudinal polarisation $F_{L}$ in the decay $B_{d} -> K^{*}mu mu$ as a function of the dimuon invariant mass is presented. A data sample of 4.9$fb^{-1}$ of integrated luminosity collected with the ATLAS detector at LHC at CERN taken in the year 2011 is used. The measurement is compared to the expectations from the Standard Model and no deviation is observed.