Search for third-generation scalar leptoquarks in the t-tau channel in proton-proton collisions at sqrt(s) = 8 TeV

TL;DR

This paper reports a search for third-generation scalar leptoquarks decaying into top quarks and tau leptons using 8 TeV proton-proton collision data, setting the first direct mass limit at 685 GeV.

Contribution

It provides the first direct experimental limit on third-generation scalar leptoquarks decaying to top and tau, using CMS data at 8 TeV.

Findings

Excluded leptoquark masses up to 685 GeV at 95% CL.

First direct limit for leptoquarks decaying into top quark and tau lepton.

Results also constrain bottom squark pair production with R-parity violation.

Abstract

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 inverse femtobarns. 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].