Study of rare and suppressed processes in B meson decays with the ATLAS experiment

The large amount of Heavy Flavor data collected by the ATLAS experiment is potentially sensitive to New Physics, which could be evident in processes that are naturally suppressed in the Standard Model. The most recent results on the search for the rare decay Bs (B0) -> mu+mu- are presented, as well as results of the angular analysis of the semileptonic rare decay Bd → K*0 mu+mu- -> K+pi-mu+mu-, extracting the distribution parameter AFB and FL (the accuracy obtained from data collected in 2011 is comparable to the best previous measurement in the region q^2(mu+mu-) -> 16 GeV^2)