Search for Scalar Leptoquark Pairs Decaying to Electrons and Jets in pbarp Collisions

TL;DR

This study searches for pair-produced first-generation scalar leptoquarks decaying to electrons and jets in proton-antiproton collisions, setting a mass limit of 225 GeV/c^2 and ruling out certain interpretations of HERA data.

Contribution

First search for scalar leptoquark pairs in the eejj channel at the Tevatron, establishing new mass limits and constraining leptoquark models.

Findings

No candidate events observed against expected background.

Set a 95% CL lower mass limit of 225 GeV/c^2 for scalar leptoquarks.

Ruled out leptoquark explanation for HERA high Q^2 excess.

Abstract

We have searched for the pair production of first generation scalar leptoquarks in the eejj channel using the full data set (123 pb-1) collected with the D0 detector at the Fermilab Tevatron during 1992--1996. We observe no candidates with an expected background of approximately 0.4 events. Comparing the experimental 95% confidence level upper limit to theoretical calculations of the cross section with the assumption of a 100% branching fraction to eq, we set a lower limit on the mass of a first generation scalar leptoquark of 225 GeV/c^2. The results of this analysis rule out the interpretation of the excess of high Q^2 events at HERA as leptoquarks which decay exclusively to eq.