Search for decays of stopped long-lived particles produced in proton-proton collisions at sqrt(s) = 8 TeV

V. Khachatryan , M. Besancon (1) , F. Couderc (1) , M. Dejardin (1) , D. Denegri (1) , B. Fabbro (1) , J.L. Faure (1) , C. Favaro (1) , F. Ferri (1) , S. Ganjour (1) , A. Givernaud (1) , P. Gras (1) , G. Hamel De Monchenault (1) , P. Jarry (1) , E. Locci (1) , J. Malcles (1) , J. Rander (1) , A. Rosowsky (1) , M. Titov (1) , S. Baffioni (2) , F. Beaudette (2) , P. Busson (2) , C. Charlot (2) , T. Dahms (2) , M. Dalchenko (2) , L. Dobrzynski (2) , N. Filipovic (2) , A. Florent (2) , R. Granier De Cassagnac (2) , L. Mastrolorenzo (2) , P. Mine (2) , C. Mironov (2) , I.N. Naranjo (2) , M. Nguyen (2) , C. Ochando (2) , G. Ortona (2) , P. Paganini (2) , S. Regnard (2) , R. Salerno (2) , J.B. Sauvan (2) , Y. Sirois (2) , C. Veelken (2) , Y. Yilmaz (2) , A. Zabi (2) , J.-L. Agram (3) , J. Andrea (3) , A. Aubin (3) , D. Bloch (3) , J.-M. Brom (3) , E.C. Chabert (3) , C. Collard (3) , E. Conte (3) , J.-C. Fontaine (3) , D. Gele (3) , U. Goerlach (3) , C. Goetzmann (3) , A.-C. Le Bihan (3) , K. Skovpen (3) , P. Van Hove (3) , S. Gadrat (4) , S. Beauceron (5) , N. Beaupere (5) , C. Bernet (5) , G. Boudoul (5) , E. Bouvier (5) , S. Brochet (5) , C.A. Carrillo Montoya (5) , J. Chasserat (5) , R. Chierici (5) , D. Contardo (5) , P. Depasse (5) , H. El Mamouni (5) , J. Fan (5) , J. Fay (5) , S. Gascon (5) , M. Gouzevitch (5) , B. Ille (5) , T. Kurca (5) , M. Lethuillier (5) , L. Mirabito (5) , S. Perries (5) , J.D. Ruiz Alvarez (5) , D. Sabes (2) , L. Sgandurra (5) , V. Sordini (5) , M. Vander Donckt (5) , P. Verdier (5) , S. Viret (5) , H. Xiao (5)

1 IRFU - Institut de Recherches sur les lois Fondamentales de l'Univers
2 LLR - Laboratoire Leprince-Ringuet
3 IPHC - Institut Pluridisciplinaire Hubert Curien
4 CC-IN2P3 - Centre de Calcul de l'IN2P3
5 IPNL - Institut de Physique Nucléaire de Lyon

A search has been performed for long-lived particles that could have come to rest within the CMS detector, using the time intervals between LHC beam crossings. The existence of such particles could be deduced from observation of their decays via energy deposits in the CMS calorimeter appearing at times that are well separated from any proton-proton collisions. Using a data set corresponding to an integrated luminosity of 18.6 inverse femtobarns of 8 TeV proton-proton collisions, and a search interval corresponding to 281 hours of trigger livetime, 10 events are observed, with a background prediction of 13.2+3.6-2.5 events. Limits are presented at 95% confidence level on gluino and top squark production, for over 13 orders of magnitude in the mean proper lifetime of the stopped particle. Assuming a cloud model of R-hadron interactions, a gluino with mass <1000 GeV and a top squark with mass <525 GeV are excluded, for lifetimes between 1 microsecond and 1000 s. These results are the most stringent constraints on stopped particles to date.

Domaines: Physique des Hautes Energies - Expérience [hep-ex]

V. Khachatryan, M. Besancon, F. Couderc, M. Dejardin, D. Denegri, et al.. Search for decays of stopped long-lived particles produced in proton-proton collisions at sqrt(s) = 8 TeV. European Physical Journal C: Particles and Fields, 2015, 75, pp.151. ⟨10.1140/epjc/s10052-015-3367-z⟩. ⟨in2p3-01128342⟩