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Combined search for the quarks of a sequential fourth generation
Chatrchyan S., Besancon M., Choudhury S., Dejardin M., Denegri D. et al
Physical Review D 86 (2012) 112003 - http://hal.in2p3.fr/in2p3-00730454
Physique/Physique des Hautes Energies - Expérience
Combined search for the quarks of a sequential fourth generation
S. Chatrchyan, M. Besancon1, S. Choudhury1, M. Dejardin1, D. Denegri1, B. Fabbro1, J.L. Faure1, F. Ferri1, S. Ganjour1, A. Givernaud1, P. Gras1, G. Hamel de Monchenault1, P. Jarry1, E. Locci1, J. Malcles1, L. Millischer1, A. Nayak1, J. Rander1, A. Rosowsky1, I. Shreyber1, M. Titov1, S. Baffioni2, F. Beaudette2, L. Benhabib2, L. Bianchini2, M. Bluj2, C. Broutin2, Pierre Busson ()2, C. Charlot2, N. Daci2, T. Dahms2, L. Dobrzynski2, R. Granier de Cassagnac2, M. Haguenauer2, P. Mine2, C. Mironov2, I.N. Naranjo2, M. Nguyen2, C. Ochando2, P. Paganini2, D. Sabes2, R. Salerno2, Y. Sirois2, C. Veelken2, A. Zabi2, J.-L. Agram3, J. Andrea3, D. Bloch3, D. Bodin3, J.-M. Brom3, M. Cardaci3, E.C. Chabert3, C. Collard3, E. Conte3, F. Drouhin3, C. Ferro3, J.-C. Fontaine3, D. Gele3, U. Goerlach3, P. Juillot3, A.-C. Le Bihan3, P. Van Hove3, F. Fassi4, D. Mercier4, S. Beauceron5, N. Beaupere5, O. Bondu5, G. Boudoul5, J. Chasserat5, R. Chierici5, D. Contardo5, P. Depasse5, H. El Mamouni5, J. Fay5, S. Gascon5, M. Gouzevitch5, B. Ille5, T. Kurca5, M. Lethuillier5, L. Mirabito5, S. Perries5, V. Sordini5, Y. Tschudi5, P. Verdier5, S. Viret5
1 :  IRFU - Institut de Recherches sur les lois Fondamentales de l'Univers (ex DAPNIA)
CEA : DSM/IRFU
France
2 :  LLR - Laboratoire Leprince-Ringuet
http://polywww.in2p3.fr/
CNRS : UMR7638 – IN2P3 – Polytechnique - X
Route de Saclay - 91128 Palaiseau Cedex
France
3 :  IPHC - Institut Pluridisciplinaire Hubert Curien
CNRS : UMR7178 – Université de Strasbourg
France
4 :  CC IN2P3 - Centre de Calcul de l'inst. national de phy. nucléaire et de phy. des particules
http://cc.in2p3.fr/
CNRS : USR6402 – IN2P3
12-14, boulevard Niels Bohr 69622 VILLEURBANNE CEDEX
France
5 :  IPNL - Institut de Physique Nucléaire de Lyon
http://www.ipnl.in2p3.fr/
CNRS : UMR5822 – IN2P3 – Université Claude Bernard - Lyon I (UCBL)
France
Results are presented from a search for a fourth generation of quarks produced singly or in pairs in a data set corresponding to an integrated luminosity of 5 inverse femtobarns recorded by the CMS experiment at the LHC in 2011. A novel strategy has been developed for a combined search for quarks of the up- and down-type in decay channels with at least one isolated muon or electron. Limits on the mass of the fourth-generation quarks and the relevant CKM matrix elements are derived in the context of a simple extension of the standard model with a sequential fourth generation of fermions. The existence of mass-degenerate fourth-generation quarks with masses below 685 GeV is excluded at 95% confidence level for minimal off-diagonal mixing between the third- and the fourth-generation quarks. With a mass difference of 25 GeV between the quark masses, the obtained limit on the masses of the fourth-generation quarks shifts by about +/- 20 GeV. This result significantly reduces the allowed parameter space for a fourth generation of fermions.
CMS

Articles dans des revues avec comité de lecture
2012
Physical Review D (Phys. Rev. D)
Publisher American Physical Society
ISSN 1550-7998 (eISSN : 1550-2368)
86
112003

Submitted to Phys. Rev. D, see paper for full list of authors
Lien vers le texte intégral : 
http://fr.arXiv.org/abs/1209.1062