Search for Third Generation Scalar Leptoquarks in the t-tau Channel with the CMS Detector

A search for pair production of third generation scalar leptoquarks decaying to a top quark and a tau lepton is presented using 19.5/fb of proton-proton collision data at a center-of-mass energy of 8 TeV collected by the CMS detector at the LHC. The search is performed using events that contain a same-sign muon and hadronically decaying tau lepton pair, 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 550 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, as well as the first CMS result in the same-sign muon - hadronically decaying tau lepton final state at 8 TeV. The result is also directly applicable to pair produced bottom squarks decaying via the R-parity violating coupling lambda-prime-333.