Search for vector-like B quarks in events with one isolated lepton, missing transverse momentum and jets at √s = 8 TeV with the ATLAS detector

ATLAS, Collaboration; Beck, Hans Peter; Cervelli, Alberto; Ereditato, Antonio; Haug, Sigve; Kabana, Sonja; Meloni, Federico; Mullier, Geoffrey André Adrien; Pretzl, Klaus-Peter; Stramaglia, Maria Elena; Stucci, Stefania; Weber, Michael (2015). Search for vector-like B quarks in events with one isolated lepton, missing transverse momentum and jets at √s = 8 TeV with the ATLAS detector. Physical review. D - particles, fields, gravitation, and cosmology, D91(11), p. 112011. American Physical Society 10.1103/PhysRevD.91.112011

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A search has been performed for pair production of heavy vector-like down-type (B ) quarks. The analysis explores the lepton-plus-jets final state, characterized by events with one isolated charged lepton (electron or muon), significant missing transverse momentum and multiple jets. One or more jets are required to be tagged as arising from b -quarks, and at least one pair of jets must be tagged as arising from the hadronic decay of an electroweak boson. The analysis uses the full data sample of pp collisions recorded in 2012 by the ATLAS detector at the LHC, operating at a center-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 20.3 fb −1 . No significant excess of events is observed above the expected background. Limits are set on vector-like B production, as a function of the B branching ratios, assuming the allowable decay modes are B→Wt/Zb/Hb . In the chiral limit with a branching ratio of 100% for the decay B→Wt , the observed (expected) 95% CL lower limit on the vector-like B mass is 810 GeV (760 GeV). In the case where the vector-like B quark has branching ratio values corresponding to those of an SU(2) singlet state, the observed (expected) 95% CL lower limit on the vector-like B mass is 640 GeV (505 GeV). The same analysis, when used to investigate pair production of a colored, charge 5/3 exotic fermion T 5/3 , with subsequent decay T 5/3 →Wt , sets an observed (expected) 95% CL lower limit on the T 5/3 mass of 840 GeV (780 GeV).

Item Type:

Journal Article (Original Article)

Division/Institute:

10 Strategic Research Centers > Albert Einstein Center for Fundamental Physics (AEC)
08 Faculty of Science > Physics Institute > Laboratory for High Energy Physics (LHEP)

UniBE Contributor:

Beck, Hans Peter; Cervelli, Alberto; Ereditato, Antonio; Haug, Sigve; Meloni, Federico; Mullier, Geoffrey André Adrien; Pretzl, Klaus-Peter; Stramaglia, Maria Elena; Stucci, Stefania and Weber, Michael

Subjects:

500 Science > 530 Physics

ISSN:

1550-7998

Publisher:

American Physical Society

Language:

English

Submitter:

Annette Krebs-Wegenast

Date Deposited:

07 Sep 2016 15:24

Last Modified:

11 Sep 2016 02:11

Publisher DOI:

10.1103/PhysRevD.91.112011

ArXiv ID:

1503.05425

Additional Information:

Kollaboration - Es sind nur die Berner Autoren namentlich erwähnt

BORIS DOI:

10.7892/boris.87643

URI:

https://boris.unibe.ch/id/eprint/87643

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