Rare Decays in LHCb.

The rare B decays B(s)0 → μ+μ-, B0 → K*0 μ+μ- and Bs0 → Φγ are studied using up to ∼ 0 41 fb-1 of pp collisions at √s = 7 TeV collected by the LHCb experiment in 2010 and 2011. A search for the decays B(s)0 → μ+μ- is performed with 0.41 fb-1. The absence of significant signal leads to B(B(s)0 → μ+μ-) 1.4 x 10-8 and B(B0 → μ+μ-) 3.2 x 10-9 at 95% confidence level. The forward-backward asymmetry, fraction of longitudinal polarization and differential branching fraction of B0 → K*0 μ+μ-, as a function of dimuon invariant mass, are measured in 0 31 fb-1. The ratio of branching ratios of the radiative B decays B0 → K*0 and Bs0 → has been measured using 0.34 fb-1. The obtained value for the ratio is 1.52 ± 0.14(stat) ± 0.10(syst) ± 0.12( fs/fd). Using the HFAG value for B(B0 → K*0 γ), B(Bs0 → Φγ) has been found to be (2.8 ± 0.5) x 10-5. [ABSTRACT FROM AUTHOR]