Search for 1st-Generation Leptoquarks Using the ATLAS Detector

TL;DR

This paper reports a search for first-generation scalar leptoquarks in proton-proton collision data from the ATLAS detector, setting mass exclusion limits based on the absence of observed excess events.

Contribution

It presents the first search for first-generation scalar leptoquarks using 7 TeV ATLAS data, establishing new mass exclusion limits.

Findings

No excess events observed in the analyzed channels.

Excluded scalar leptoquark masses below 660 GeV at 95% confidence level.

Set limits for different decay branching fractions.

Abstract

A search for the pair-production of scalar leptoquarks in 1/fb of 7 TeV ATLAS data recorded at the LHC is presented. Leptoquarks are hypothetical color-triplet bosons which carry both quark and lepton flavor, and thus decay to a quark and a lepton, unlike any of the Standard Model particles. Leptoquarks arise from many beyond the Standard Model theories. The channels examined in this analysis require at least one leptoquark decay to an electron, which includes the final states eejj and evjj. No excess of events is observed, thus limits on allowed leptoquark masses are determined. We exclude at 95% confidence level the production of first-generation scalar leptoquarks with mass m < 660 (607) GeV when assuming a branching fraction of leptoquark decay to an electron of 1.0 (0.5).