The LHCb experiment has measured the isospin asymmetry (AI) in B->K(*)MuMu decays with 1fb-1 of integrated luminosity collected during 2011. The SM prediction for AI is O(1%). Previous measurements, particularly by BaBar collaboration have measured a significantly negative AI in the low di-muon invariant mass region. This measurement has been an anomaly in B physics for the last few years (the latest HFAG average is over 4sigma from zero). The large b-bbar cross section at the LHC gives LHCb the sensitivity to either confirm this anomaly or finally put this unexpected result to rest.
