Search for pair production of first- and second-generation scalar leptoquarks in pp collisions at sqrt(s) = 7 TeV

TL;DR

This study searches for pair-produced scalar leptoquarks in proton-proton collisions at 7 TeV, setting new mass exclusion limits up to 840 GeV based on CMS detector data, with different assumptions on decay branching ratios.

Contribution

It provides the most stringent limits to date on first- and second-generation scalar leptoquark masses using CMS data at 7 TeV.

Findings

Excluded leptoquark masses below 830-840 GeV for beta=1.

Excluded leptoquark masses below 640-650 GeV for beta=0.5.

Set new upper limits on leptoquark production cross sections.

Abstract

Results are presented from a search for the pair production of first- and second-generation scalar leptoquarks in proton-proton collisions at sqrt(s) = 7 TeV. The data sample corresponds to an integrated luminosity of 5.0 inverse femtobarns, collected by the CMS detector at the LHC. The search signatures involve either two charged leptons of the same-flavor (electrons or muons) and at least two jets, or a single charged lepton (electron or muon), missing transverse energy, and at least two jets. If the branching fraction of the leptoquark decay into a charged lepton and a quark is assumed to be beta = 1, leptoquark pair production is excluded at the 95% confidence level for masses below 830 GeV and 840 GeV for the first and second generations, respectively. For beta = 0.5, masses below 640 GeV and 650 GeV are excluded. These limits are the most stringent to date.