We present generalizations of the Crystal-Ball function to describe mass peaks in which the per-event mass resolution is unknown and marginalized over. The presented probability density functions are tested using a series of toy-MC samples generated
with Pythia and smeared with different amounts of multiple scattering and for different detector resolutions.
The rare B decays Bs(d)-->mumu, B-->K*mumu and Bs-->phigamma are studied using up to sim 0.41 fb^{-1} of pp collisions at sqrt{s} = 7 TeV collected by the lhcb experiment in 2010 and 2011. A search for the decays Bs(d)-->mumu, is performed with 0.41
fb^{-1} . The absence of significant signal leads to BR(Bs-->mumu<1.4 x 10^{-8} and BR(Bd-->mumu<3.2 x 10^{-9} at 95% confidence level. The forward-backward asymmetry, fraction of longitudinal polarization and differential branching fraction of B-->K*mumu, as a function of dimuon invariant mass, are measured in 0.31 fb^{-1}. The ratio of branching ratios of the radiative B decays B--> K*gamma and Bs-->phigamma h as been measured using 0.34fb^{-1}. The obtained value for the ratio is 1.52 pm 0.14 (stat) pm 0.10 (syst) pm 0.12 (f_s/f_d). Using the HFAG value for BR(Bd --> K^*gamma), BR(Bs-->phigamma) has been found to be (2.8 pm 0.5)times 10^{-5}.
