@article{cbc252a5280d4bb295467f2d0ac6d004,
title = "Analysis of the Wtb vertex from the measurement of triple-differential angular decay rates of single top quarks produced in the t-channel at √s=8 TeV with the ATLAS detector",
abstract = "The electroweak production and subsequent decay of single top quarks in the t-channel is determined by the properties of the Wtb vertex, which can be described by the complex parameters of an effective Lagrangian. An analysis of a triple-differential decay rate in t-channel production is used to simultaneously determine five generalised helicity fractions and phases, as well as the polarisation of the produced top quark. The complex parameters are then constrained. This analysis is based on 20.2 fb−1 of proton-proton collision data at a centre-of-mass energy of 8 TeV collected with the ATLAS detector at the LHC. The fraction of decays containing transversely polarised W bosons is measured to be f1 = 0.30 ± 0.05. The phase between amplitudes for transversely and longitudinally polarised W bosons recoiling against left-handed b-quarks is measured to be δ− = 0.002π+ 0.017π + 0.016π, giving no indication of CP violation. The fractions of longitudinal or transverse W bosons accompanied by right-handed b-quarks are also constrained. Based on these measurements, limits are placed at 95% CL on the ratio of the complex coupling parameters Re [gR/VL ∈ [−0.12, 0.17] and Im [gR/VL ∈ [−0.07, 0.06]. Constraints are also placed on the ratios |VR/VL| and |gL/VL|. In addition, the polarisation of single top quarks in the t-channel is constrained to be P > 0.72 (95% CL). None of the above measurements make assumptions about the value of any of the other parameters or couplings and all of them are in agreement with the Standard Model.[Figure not available: see fulltext.].",
keywords = "Electroweak interaction, Hadron-Hadron scattering (experiments), Top physics",
author = "{The ATLAS collaboration} and M. Aaboud and G. Aad and B. Abbott and J. Abdallah and O. Abdinov and B. Abeloos and Abidi, {S. H.} and AbouZeid, {O. S.} and Abraham, {N. L.} and H. Abramowicz and H. Abreu and R. Abreu and Y. Abulaiti and Acharya, {B. S.} and S. Adachi and L. Adamczyk and J. Adelman and M. Adersberger and T. Adye and Affolder, {A. A.} and T. Agatonovic-Jovin and C. Agheorghiesei and Aguilar-Saavedra, {J. A.} and Ahlen, {S. P.} and F. Ahmadov and G. Aielli and S. Akatsuka and H. Akerstedt and {\AA}kesson, {T. P.A.} and E. Akilli and Akimov, {A. V.} and Alberghi, {G. L.} and J. Albert and P. Albicocco 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 B. Ali and M. Aliev and G. Alimonti and J. Alison and Alkire, {S. P.} and Allbrooke, {B. M.M.} and Allen, {B. W.} and Allport, {P. P.} and A. Aloisio and A. Alonso and F. Alonso and C. Alpigiani and Alshehri, {A. A.} and Alstaty, {M. I.} and {Alvarez Gonzalez}, B. and {{\'A}lvarez Piqueras}, D. and Alviggi, {M. G.} and Amadio, {B. T.} and {Amaral Coutinho}, Y. and C. Amelung and D. Amidei and {Amor Dos Santos}, {S. P.} and A. Amorim and S. Amoroso and G. Amundsen and C. Anastopoulos and Ancu, {L. S.} and N. Andari and T. Andeen and Anders, {C. F.} and Anders, {J. K.} and Anderson, {K. J.} and A. Andreazza and V. Andrei and S. Angelidakis and I. Angelozzi and A. Angerami and Anisenkov, {A. V.} and N. Anjos and A. Annovi and C. Antel and M. Antonelli and A. Antonov and Antrim, {D. J.} and F. Anulli and M. Aoki and {Aperio Bella}, L. and G. Arabidze and Y. Arai and Araque, {J. P.} and {Araujo Ferraz}, V. and Arce, {A. T.H.} and Ardell, {R. E.} and Arduh, {F. A.} and Arguin, {J. F.} and S. Argyropoulos and M. Arik and Armbruster, {A. J.} and Armitage, {L. J.} and O. Arnaez and H. Arnold and M. Arratia and O. Arslan and A. Artamonov and G. Artoni and S. Artz and S. Asai and N. Asbah and A. Ashkenazi and L. Asquith and K. Assamagan and R. Astalos and M. Atkinson and Atlay, {N. B.} and K. Augsten and G. Avolio and B. Axen and Ayoub, {M. K.} and G. Azuelos and Baas, {A. E.} and Baca, {M. J.} and H. Bachacou and K. Bachas and M. Backes and M. Backhaus and P. Bagnaia and H. Bahrasemani and Baines, {J. T.} and M. Bajic and Baker, {O. K.} and Baldin, {E. M.} and P. Balek 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 Barisits, {M. S.} and Barkeloo, {J. T.} and T. Barklow and N. Barlow and Barnes, {S. L.} and Barnett, {B. M.} and Barnett, {R. M.} and Z. Barnovska-Blenessy and A. Baroncelli and G. Barone and Barr, {A. J.} and {Barranco Navarro}, L. 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 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 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 M. Bedognetti and Bee, {C. P.} and Beermann, {T. A.} and M. Begalli and M. Begel and Behr, {J. K.} and Bell, {A. S.} and G. Bella and L. Bellagamba and A. Bellerive and M. Bellomo and K. Belotskiy and O. Beltramello and Belyaev, {N. L.} and O. Benary and D. Benchekroun and M. Bender and X. Zhao",
note = "Publisher Copyright: {\textcopyright} 2017, The Author(s).",
year = "2017",
month = dec,
day = "1",
doi = "10.1007/JHEP12(2017)017",
language = "English",
volume = "2017",
journal = "Journal of High Energy Physics",
issn = "1126-6708",
number = "12",
}