Search for decays of stopped, long-lived particles from 7 TeV pp collisions with the ATLAS detector

TL;DR

This paper reports a search for long-lived, stopped gluino-based R-hadrons in 7 TeV proton-proton collisions using the ATLAS detector, setting mass and lifetime exclusion limits.

Contribution

First search for stopped, long-lived gluino R-hadrons in ATLAS data, establishing new mass and lifetime constraints.

Findings

No significant signal observed.

Excluded gluino R-hadrons with masses below 341 GeV.

Set limits on particle lifetimes from 10^-5 to 10^3 seconds.

Abstract

New metastable massive particles with electric and colour charge are features of many theories beyond the Standard Model. A search is performed for long-lived gluino-based R-hadrons with the ATLAS detector at the LHC using a data sample corresponding to an integrated luminosity of 31 pb^-1. We search for evidence of particles that have come to rest in the ATLAS detector and decay at some later time during the periods in the LHC bunch structure without proton-proton collisions. No significant deviations from the expected backgrounds are observed, and a cross-section limit is set. It can be interpreted as excluding gluino-based R-hadrons with masses less than 341 GeV at the 95% C.L., for lifetimes from 10^-5 to 10^3 seconds and a neutralino mass of 100 GeV.