Search for third generation leptoquarks in tau+b

A search for third generation leptoquarks and stops using events from a data sample of pp collisions corresponding to an integrated luminosity of 4.8~\fbinv, collected by the CMS detector at the LHC with $\sqrt{s}=7$~\TeV is presented. The number of observed events containing two taus and two b jets is found to be in agreement with the standard model prediction. A 95\% CL limit is set on the scalar (vector) leptoquark pair production cross section times $\beta^2$, where $\beta$ is the branching fraction of leptoquark to a tau and a b quark. The third generation leptoquarks with masses below 525~\GeV (for $\beta=1$) and SU(5) vector leptoquarks with masses below 760~GeV are excluded at 95\% CL. Limits are also set on the cross section for pair production of the supersymmetric partner of the top quark (stop) in R-parity violating supersymmetric scenario. Stops with masses below 453~\GeV are excluded at 95\%~CL for a typical benchmark scenario, assuming coupling between stop, tau, and b quark, $\lambda^{\prime}_{333}=1$. Both of these results represent the most stringent mass limits on these particles to date. The stringent limits on $\lambda^{\prime}_{333}$ are also set excluding coupling values not ruled out by indirect bounds.