@article{6fa25949ea5f4deab13d204caa4ec53e,

title = "Search for flavour-changing neutral current top quark decays t → Hq in pp collisions at √s=8 TeV with the ATLAS detector",

abstract = "Abstract: A search for flavour-changing neutral current decays of a top quark to an uptype quark (q = u, c) and the Standard Model Higgs boson, where the Higgs boson decays to(Formula Presented.), is presented. The analysis searches for top quark pair events in which one top quark decays to Wb, with the W boson decaying leptonically, and the other top quark decays to Hq. 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 uses 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 and at least four jets. The search exploits the high multiplicity of b-quark jets characteristic of signal events, and employs a likelihood discriminant that uses the kinematic differences between the signal and the background, which is dominated by (Formula Presented.) decays. No significant excess of events above the background expectation is found, and observed (expected) 95% CL upper limits of 0.56% (0.42%) and 0.61% (0.64%) are derived for the t → Hc and t → Hu branching ratios respectively. The combination of this search with other ATLAS searches in the H → γγ and H → WW*, ττ decay modes significantly improves the sensitivity, yielding observed (expected) 95% CL upper limits on the t → Hc and t → Hu branching ratios of 0.46% (0.25%) and 0.45% (0.29%) respectively. The corresponding combined observed (expected) upper limits on the |λtcH| and |λtuH| couplings are 0.13 (0.10) and 0.13 (0.10) respectively. These are the most restrictive direct bounds on tqH interactions measured so far.[Figure not available: see fulltext.]",

keywords = "FCNC Interactions, Hadron-Hadron Scattering, Higgs Physics, Top Physics",

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 J. Agricola 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 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 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 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 Baca, {M. J.} 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 Baldin, {E. M.} and P. Balek and T. Balestri and F. Balli and Balunas, {W. K.} and E. Banas and Sw Banerjee and Bannoura, {A. A.E.} 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 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 N. Benekos and X. Zhao",

note = "Publisher Copyright: {\textcopyright} 2015, The Author(s).",

year = "2015",

month = dec,

day = "1",

doi = "10.1007/JHEP12(2015)061",

language = "English",

volume = "2015",

pages = "1--65",

journal = "Journal of High Energy Physics",

issn = "1126-6708",

number = "12",

}