@article{7a91af86def043058b9fc22771cdbefa,
title = "Search for production of vector-like quark pairs and of four top quarks in the lepton-plus-jets final state in pp collisions at √s = 8 TeV with the ATLAS detector",
abstract = "A search for pair production of vector-like quarks, both up-type (T) and down-type (B), as well as for four-top-quark production, is presented. The search is based on pp collisions at (Formula presented.) TeV recorded in 2012 with the ATLAS detector at the CERN Large Hadron Collider and corresponding to an integrated luminosity of 20.3 fb−1. Data are analysed in the lepton-plus-jets final state, characterised by an isolated electron or muon with high transverse momentum, large missing transverse momentum and multiple jets. Dedicated analyses are performed targeting three cases: a T quark with significant branching ratio to a W boson and a b-quark (TT¯→Wb+X), and both a T quark and a B quark with significant branching ratio to a Higgs boson and a third-generation quark (TT¯→Ht+XandBB¯→Hb+X respectively). No significant excess of events above the Standard Model expectation is observed, and 95% CL lower limits are derived on the masses of the vector-like T and B quarks under several branching ratio hypotheses assuming contributions from T → Wb, Zt, Ht and B → Wt, Zb, Hb decays. The 95% CL observed lower limits on the T quark mass range between 715 GeV and 950 GeV for all possible values of the branching ratios into the three decay modes, and are the most stringent constraints to date. Additionally, the most restrictive upper bounds on four-top-quark production are set in a number of new physics scenarios.",
keywords = "Hadron-Hadron Scattering",
author = "{The ATLAS collaboration} and G. Aad and B. Abbott and J. Abdallah and O. Abdinov and R. Aben and M. Abolins and AbouZeid, {O. S.} and H. Abramowicz and H. Abreu and R. Abreu and Y. Abulaiti and Acharya, {B. S.} and L. Adamczyk and Adams, {D. L.} and J. Adelman and S. Adomeit and T. Adye and Affolder, {A. A.} and T. Agatonovic-Jovin and Aguilar-Saavedra, {J. A.} and Ahlen, {S. P.} and F. Ahmadov and G. Aielli and H. Akerstedt and {\AA}kesson, {T. P.A.} and G. Akimoto and Akimov, {A. V.} and Alberghi, {G. L.} and J. Albert and S. Albrand and {Alconada Verzini}, {M. J.} and M. Aleksa and Aleksandrov, {I. N.} and C. Alexa and G. Alexander and T. Alexopoulos and M. Alhroob and G. Alimonti and L. Alio and J. Alison and Alkire, {S. P.} and Allbrooke, {B. M.M.} and Allport, {P. P.} and A. Aloisio and A. Alonso and F. Alonso and C. Alpigiani and A. Altheimer and {Alvarez Gonzalez}, B. and {{\'A}lvarez Piqueras}, D. and Alviggi, {M. G.} and Amadio, {B. T.} and K. Amako and {Amaral Coutinho}, Y. and C. Amelung and D. Amidei and {Amor Dos Santos}, {S. P.} and A. Amorim and S. Amoroso and N. Amram and G. Amundsen and C. Anastopoulos and Ancu, {L. S.} and N. Andari and T. Andeen and Anders, {C. F.} and G. Anders and Anders, {J. K.} and Anderson, {K. J.} and A. Andreazza and V. Andrei and S. Angelidakis and I. Angelozzi and P. Anger and A. Angerami and F. Anghinolfi and Anisenkov, {A. V.} and N. Anjos and A. Annovi and M. Antonelli and A. Antonov and J. Antos and F. Anulli and M. Aoki and {Aperio Bella}, L. and G. Arabidze and Y. Arai and Araque, {J. P.} and Arce, {A. T.H.} and Arduh, {F. A.} and Arguin, {J. F.} and S. Argyropoulos and M. Arik and Armbruster, {A. J.} and O. Arnaez and V. Arnal and H. Arnold and M. Arratia and O. Arslan and A. Artamonov and G. Artoni and S. Asai and N. Asbah and A. Ashkenazi and B. {\AA}sman and L. Asquith and K. Assamagan and R. Astalos and M. Atkinson and Atlay, {N. B.} and B. Auerbach and K. Augsten and M. Aurousseau and G. Avolio and B. Axen and Ayoub, {M. K.} and G. Azuelos and Baak, {M. A.} and Baas, {A. E.} and C. Bacci and H. Bachacou and K. Bachas and M. Backes and M. Backhaus and P. Bagiacchi and P. Bagnaia and Y. Bai and T. Bain and Baines, {J. T.} and Baker, {O. K.} and P. Balek and T. Balestri and F. Balli and E. Banas and Sw Banerjee and Bannoura, {A. A.E.} and Bansil, {H. S.} and L. Barak and Barberio, {E. L.} and D. Barberis and M. Barbero and T. Barillari and M. Barisonzi and T. Barklow and N. Barlow and Barnes, {S. L.} and Barnett, {B. M.} and Barnett, {R. M.} and Z. Barnovska and A. Baroncelli and G. Barone and Barr, {A. J.} and F. Barreiro and {Barreiro Guimar{\~a}es da Costa}, J. and R. Bartoldus and Barton, {A. E.} and P. Bartos and A. Basalaev and A. Bassalat and A. Basye and Bates, {R. L.} and Batista, {S. J.} and Batley, {J. R.} and M. Battaglia and M. Bauce and F. Bauer and Bawa, {H. S.} and Beacham, {J. B.} and Beattie, {M. D.} and T. Beau and Beauchemin, {P. H.} and R. Beccherle and P. Bechtle and Beck, {H. P.} and K. Becker and M. Becker and S. Becker and M. Beckingham and C. Becot and Beddall, {A. J.} and A. Beddall and Bednyakov, {V. A.} and Bee, {C. P.} and Beemster, {L. J.} and Beermann, {T. A.} and M. Begel and Behr, {J. K.} and C. Belanger-Champagne and Bell, {W. H.} and G. Bella and L. Bellagamba and A. Bellerive and M. Bellomo and K. Belotskiy and O. Beltramello and O. Benary and D. Benchekroun and M. Bender and K. Bendtz and X. Zhao",
note = "Publisher Copyright: {\textcopyright} 2015, The Author(s).",
year = "2015",
month = aug,
day = "31",
doi = "10.1007/JHEP08(2015)105",
language = "English",
volume = "2015",
journal = "Journal of High Energy Physics",
issn = "1126-6708",
number = "8",
}