Search For Third Generation Scalar Leptoquarks Decaying Into A Top Quark And A Tau Lepton With The Cms Detector

Search for Third-generation Scalar Leptoquarks Decaying Into a Top Quark and a Tau Lepton with the CMS Detector

Search for Third-Generation Scalar Leptoquarks in the T$\tau$ Channel in Proton-Proton Collisions at $\sqrt{s}$

A search for pair production of third-generation scalar leptoquarks decaying to top quark and $\tau$ lepton pairs is presented using proton-proton collision data at a center-of-mass energy of $\sqrt{s}$ = 8 TeV collected with the CMS detector at the LHC and corresponding to an integrated luminosity of 19.7 fb-1. The search is performed using events that contain an electron or a muon, a hadronically decaying $\tau$ lepton, and two or more jets. The observations are found to be consistent with the standard model predictions. Assuming that all leptoquarks decay to a top quark and a $\tau$ lepton, the existence of pair produced, charge -1/3, third-generation leptoquarks up to a mass of 685 GeV is excluded at 95% confidence level. This result constitutes the first direct limit for leptoquarks decaying into a top quark and a $\tau$ lepton, and may also be applied directly to the pair production of bottom squarks decaying predominantly via the R-parity violating coupling [lambda]' 333.

Search for Pair Production of Third-generation Scalar Leptoquarks and Top Squarks in Proton-proton Collisions at [arrow]"

A search for pair production of third-generation scalar leptoquarks and supersymmetric top quark partners, top squarks, in final states involving tau leptons and bottom quarks is presented. The search uses events from a data sample of proton-proton collisions corresponding to an integrated luminosity of 19.7 fb-1, collected with the CMS detector at the LHC with [arrow]" = 8 TeV. The number of observed events is found to be in agreement with the expected standard model background. Third-generation scalar leptoquarks with masses below 740 GeV are excluded at 95% confidence level, assuming a 100% branching fraction for the leptoquark decay to a tau lepton and a bottom quark. In addition, this mass limit applies directly to top squarks decaying via an R-parity violating coupling [lambda]'333. The search also considers a similar signature from top squarks undergoing a chargino-mediated decay involving the R-parity violating coupling [lambda]'3jk. Each top squark decays to a tau lepton, a bottom quark, and two light quarks. Top squarks in this model with masses below 580 GeV are excluded at 95% confidence level. The constraint on the leptoquark mass is the most stringent to date, and this is the first search for top squarks decaying via [lambda]'3jk.