TY - JOUR
T1 - Search for long-lived stopped R-hadrons decaying out of time with pp collisions using the ATLAS detecto
AU - Aad, G.
AU - Abajyan, T.
AU - Abbott, B.
AU - Abdallah, J.
AU - Khalek, S.A.
AU - Dam, Mogens
AU - Hansen, Jørgen Beck
AU - Hansen, Peter Henrik
AU - Hansen, John Renner
AU - Hansen, Jørn Dines
AU - Heisterkamp, Simon Johann Franz
AU - Jørgensen, Morten Dam
AU - Boelaert, Nele Maria Philomena
AU - Klinkby, Esben Bryndt
AU - Løvschall-Jensen, Ask Emil
AU - Mehlhase, Sascha
AU - Nilsson, Björn Stefan
AU - Petersen, Troels Christian
AU - Xella, Stefania
PY - 2013/12/3
Y1 - 2013/12/3
N2 - 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 fb-1 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 μs and 1000 s in the generic R-hadron model with equal branching ratios for decays to (formula presented) and (formula presented). 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.
AB - 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 fb-1 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 μs and 1000 s in the generic R-hadron model with equal branching ratios for decays to (formula presented) and (formula presented). 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.
U2 - 10.1103/PhysRevD.88.112003
DO - 10.1103/PhysRevD.88.112003
M3 - Journal article
SN - 1550-7998
VL - 88
SP - 88
JO - Physical Review D (Particles, Fields, Gravitation and Cosmology)
JF - Physical Review D (Particles, Fields, Gravitation and Cosmology)
IS - 11
M1 - 112003
ER -