Search for Squark Production in R-Parity Violating Supersymmetry at HERA

TL;DR

This paper reports a search for squarks in R-parity violating supersymmetry at HERA, setting mass limits up to 275 GeV for certain coupling strengths, with no evidence of squark production found.

Contribution

First search at HERA for squarks via R-parity violation considering multiple decay modes, establishing new mass limits within the MSSM and supergravity frameworks.

Findings

No evidence for squark production in analyzed channels.

Mass limits exclude squarks up to 275 GeV for electromagnetic strength coupling.

Constraints on supersymmetric model parameters derived from null results.

Abstract

A search for squarks in R-parity violating supersymmetry is performed in e+/- p collisions at HERA using the H1 detector. The data were taken at a centre-of-mass energy of 319 GeV and correspond to an integrated luminosity of 64.3 pb-1 for e+p collisions and 13.5 pb-1 for e-p collisions. The resonant production of squarks via a Yukawa coupling lambda' is considered, taking into account direct and indirect R-parity violating decay modes. No evidence for squark production is found in the multi-lepton and multi-jet final state topologies investigated. Mass dependent limits on lambda' are obtained in the framework of the Minimal Supersymmetric Standard Model. In addition, the results are interpreted in terms of constraints on the parameters of the minimal Supergravity model. At the 95% confidence level squarks of all flavours with masses up to 275 GeV are excluded in a large part of the parameter space for a Yukawa coupling of electromagnetic strength. For a coupling strength 100 times smaller, masses up to 220 GeV can be ruled out.