Search for First-Generation Scalar Leptoquarks in $\bm{p \bar{p}}$ collisions at $\sqrt{s}$=1.96 TeV

TL;DR

This paper reports a search for first-generation scalar leptoquarks in proton-antiproton collisions at 1.96 TeV, setting mass limits based on non-observation in various decay channels using data from the Fermilab Tevatron.

Contribution

It provides the first combined limits on leptoquark masses as a function of branching ratio using Tevatron data, improving constraints on their existence.

Findings

No evidence for leptoquark production was observed.

Mass limits of 236, 205, and 145 GeV/c^2 were set for different branching ratios.

The results constrain models predicting first-generation scalar leptoquarks.

Abstract

We report on a search for pair production of first-generation scalar leptoquarks ($LQ$) in $p \bar{p}$ collisions at $\sqrt{s}$=1.96 TeV using an integrated luminosity of 203 $pb^{-1}$ collected at the Fermilab Tevatron collider by the CDF experiment. We observe no evidence for $LQ$ production in the topologies arising from $LQ \bar{LQ} \to eqeq$ and $LQ \bar{LQ} \to eq \nu q$, and derive 95% C.L. upper limits on the $LQ$ production cross section. %as a function of $\beta$, where $\beta$ is the branching fraction for $LQ \to eq$. The results are combined with those obtained from a separately reported CDF search in the topology arising from $LQ\bar{LQ} \to \nu q \nu q$ and 95% C.L. lower limits on the LQ mass as a function of $\beta = BR(LQ \to eq) $ are derived. The limits are 236, 205 and 145 GeV/c$^2$ for $\beta$ = 1, $\beta$ = 0.5 and $\beta$ = 0.1, respectively.