Search for gauge mediated SUSY breaking topologies in e+e- collisions at centre-of-mass energies up to 209GeV

TL;DR

This study analyzed 628 pb^-1 of data from ALEPH at energies up to 209 GeV to search for gauge mediated SUSY breaking signatures, setting new mass limits on supersymmetric particles and the NLSP.

Contribution

First comprehensive search for multiple GMSB topologies at LEP energies, establishing new lower mass limits for NLSP and SUSY particles independent of NLSP lifetime.

Findings

No evidence for SUSY signals was observed.

Lower limit on NLSP mass set at 77 GeV/c^2.

Excluded SUSY mass scale parameter Λ up to 16 TeV/c^2.

Abstract

A total of 628$\invpb$ of data collected with the ALEPH detector at centre-of-mass energies from 189 to 209 GeV is analysed in the search for gauge mediated SUSY breaking (GMSB) topologies. These topologies include two acoplanar photons, non-pointing single photons, acoplanar leptons, large impact parameter leptons, detached slepton decay vertices, heavy stable charged sleptons and multi-leptons plus missing energy final states. No evidence is found for new phenomena, and lower limits on masses of supersymmetric particles are derived. A scan of a minimal GMSB parameter space is performed and lower limits are set for the next-to-lightest supersymmetric particle (NLSP) mass at 54$\gevcc$ and for the mass scale parameter $\Lambda$ at 10$\tevcc$, independently of the NLSP lifetime. Including the results from the neutral Higgs boson searches, a NLSP mass limit of 77$\gevcc$ is obtained and values of $\Lambda$ up to 16$\tevcc$ are excluded.