Searches for Lepton Flavor Universality Violation at CMS

In this talk recent new results from CMS on the search for New Physics effects in heavy flavor decays are presented. Particularly, lepton flavor unification violation was searched for by measuring $$R(K)$$ and $$R(J/\psi)$$ ratios. Also, lepton flavor violating decay $$\tau\rightarrow 3\mu$$ was searched for and upper limit on its branching fraction was extracted. The discussed results were obtained with the RUN II data of pp collisions at $$\sqrt{s}=13$$ TeV.