Search for long-lived stopped R-hadrons decaying out of time with pp collisions using the ATLAS detector

An updated search is performed for gluino, top squark, or bottom squark R-hadrons that have come to
rest within the ATLAS calorimeter, and decay at some later time to hadronic jets and a neutralino, using
5.0 and 22:9 fb1 of pp collisions at 7 and 8 TeV, respectively. Candidate decay events are triggered in
selected empty bunch crossings of the LHC in order to remove pp collision backgrounds. Selections
based on jet shape and muon system activity are applied to discriminate signal events from cosmic ray and
beam-halo muon backgrounds. In the absence of an excess of events, improved limits are set on gluino,
stop, and sbottom masses for different decays, lifetimes, and neutralino masses. With a neutralino of mass
100 GeV, the analysis excludes gluinos with mass below 832 GeV (with an expected lower limit of
731 GeV), for a gluino lifetime between 10 s and 1000 s in the generic R-hadron model with equal
branching ratios for decays to q q~0 and g~0. Under the same assumptions for the neutralino mass and
squark lifetime, top squarks and bottom squarks in the Regge R-hadron model are excluded with masses
below 379 and 344 GeV, respectively.