Search for pair production of first or second generation leptoquarks in proton-proton collisions at sqrt(s)=7 TeV using the ATLAS detector at the LHC

TL;DR

This study searches for pair-produced first and second generation scalar leptoquarks in proton-proton collisions at 7 TeV using the ATLAS detector, setting mass exclusion limits based on observed data and background predictions.

Contribution

It provides the first ATLAS search for first and second generation scalar leptoquarks at 7 TeV, establishing new mass exclusion limits.

Findings

No evidence of leptoquark production was observed.

Masses below 376 GeV for first generation and 319 GeV for second generation are excluded at 95% CL.

Limits depend on the assumed branching fractions of leptoquarks.

Abstract

This paper describes searches for the pair production of first or second generation scalar leptoquarks using 35/pb of proton-proton collision data recorded by the ATLAS detector at sqrt(s)=7 TeV. Leptoquarks are seached in events with two oppositely charged muons or electrons and at least two jets, and in events with one muon or electron, missing transverse momentum and at least two jets. After event selection, the observed yields are consistent with the predicted backgrounds. Leptoquark production is excluded at the 95% CL for masses mLQ<376 (319) GeV and mLQ<422 (362) GeV for first and second generation scalar leptoquarks, respectively, when assuming the branching fraction of a leptoquark to a charged lepton is equal to 1.0 (0.5).