Results on $B_{s,d}\to\mu\mu$ decays and measurement of $P'_5$ and $P_1$ parameters in $B_0\to K^* \mu \mu$ decay

Phenomena beyond the standard model (SM) can manifest themself indirectly, by affecting the production and decay of SM particles.The features of $B_{d,s}\to\mu\mu$ decays are sensitive probes of physics beyond the Standard Model. This talk will review the results on these decays from the data collected by the CMS experiment. The decay $B_0\to{K^*\mu\mu}$ is a flavor-changing neutral current (FCNC)process particularly sensitive to new physics, since it is heavily suppressed in the SM. Recent results from LHCb collaboration show a tension with respect SM prediction of more than 3 sigmas, and the Belle Collaboration reported a discrepancy almost as large.We will present results of an angular analysis done by the CMS experiment at the LHC, using p-p data collected at $\sqrt{s}=8~TeV$, corresponding to an integrated luminosity of $L=20 fb^{-1}$. The analysis is focused to measure the angular parameter $P_5'$, as well as $P_1$, as a function of the di-muons invariant mass.