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

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 103 seconds and a
neutralino mass of 100 GeV.