Search for Zgamma events with large missing transverse energy in ppbar collisions at sqrt(s)=1.96 TeV

TL;DR

This paper reports the first search for supersymmetry in Zgamma final states with large missing energy in proton-antiproton collisions, setting new limits on SUSY models with gauge-mediated breaking.

Contribution

It introduces a novel search for SUSY in Zgamma + missing energy channels at Tevatron energies, providing the first experimental constraints on this scenario.

Findings

Excluded SUSY models with Lambda < 87 TeV at 95% C.L.

Set limits on neutralino masses below 151 GeV.

Demonstrated the feasibility of searching for gauge-mediated SUSY at Tevatron.

Abstract

We present the first search for supersymmetry (SUSY) in Zgamma final states with large missing transverse energy using data corresponding to an integrated luminosity of 6.2 fb-1 collected with the D0 experiment in ppbar collisions at sqrt(s)=1.96 TeV. This signature is predicted in gauge-mediated SUSY-breaking models, where the lightest neutralino is the next-to-lightest supersymmetric particle (NLSP) and is produced in pairs, possibly through decay from heavier supersymmetric particles. The NLSP can decay either to a Z boson or a photon and an associated gravitino that escapes detection. We exclude this model at the 95% C.L. for SUSY breaking scales of Lambda < 87 TeV, corresponding to neutralino masses of < 151 GeV.