Search for R-Parity Violating Decays of Scalar Fermions at LEP

TL;DR

This paper reports a search for R-parity violating decays of scalar fermions at LEP, finding no evidence and setting limits on production cross-sections and mass ranges within supersymmetric models.

Contribution

It provides the first experimental limits on scalar fermion production with R-parity violation at LEP energies, under specific decay assumptions.

Findings

No significant excess of R-parity violating events observed

Limits established on scalar fermion production cross-sections

Mass exclusion regions defined within the CMSSM framework

Abstract

A search for pair produced scalar fermions with couplings that violate R-parity has been performed using a data sample corresponding to an integrated luminosity of 56 pb-1 at a centre-of-mass energy of sqrt{s}= 183 GeV collected with the OPAL detector at LEP. An important consequence of R-parity breaking interactions is that the lightest supersymmetric particle is expected to be unstable. Searches for R-parity violating decays of charged sleptons, sneutrinos and stop quarks have been performed under the assumptions that the lightest supersymmetric particle decays promptly and that only one of the R-parity violating couplings is dominant for each of the decay modes considered. Such processes would yield multi-leptons, jets plus leptons or multi-jets, with or without missing energy, in the final state. No significant excess of such events has been observed. Limits on the production cross-sections of scalar fermions in R-parity violating scenarios are obtained. Mass exclusion regions are also presented in the framework of the Constrained Minimal Supersymmetric Standard Model.