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Abstract:

A search for single top-quark production via flavour-changing neutral current processes from gluon plus up- or charm-quark initial states in proton–proton collisions at the LHC is presented. Data collected with the ATLAS detector in 2012 at a centre-of-mass energy of 8 TeV and corresponding to an integrated luminosity of 20.3 fb (Formula presented.) are used. Candidate events for a top quark decaying into a lepton, a neutrino and a jet are selected and classified into signal- and background-like candidates using a neural network. No signal is observed and an upper limit on the production cross-section multiplied by the (Formula presented.) branching fraction is set. The observed 95 % CL limit is (Formula presented.) and the expected 95 % CL limit is (Formula presented.). The observed limit can be interpreted as upper limits on the coupling constants of the flavour-changing neutral current interactions divided by the scale of new physics (Formula presented.) and (Formula presented.) and on the branching fractions (Formula presented.) and (Formula presented.). © 2016, CERN for the benefit of the ATLAS collaboration.

Registro:

Documento: Artículo
Título:Search for single top-quark production via flavour-changing neutral currents at 8 TeV with the ATLAS detector
Autor:Aad, G. et al.
Este artículo contiene 2858 autores, consultelos en el artículo en formato pdf.
Filiación: Este artículo contiene 2858 autores con sus filiaciones, consultelas en el artículo en formato pdf.
Año:2016
Volumen:76
Número:2
Página de inicio:1
Página de fin:30
DOI: http://dx.doi.org/10.1140/epjc/s10052-016-3876-4
Título revista:European Physical Journal C
Título revista abreviado:Eur. Phys. J. C
ISSN:14346044
Registro:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_14346044_v76_n2_p1_Aad

Referencias:

  • ATLAS, CDF, CMS, D0 Collaborations, First combination of Tevatron and LHC measurements of the top-quark mass (2014). [hep-ex]; G. Eilam, J.L. Hewett and A. Soni, Rare decays of the top quark in the standard and two-Higgs-doublet models. Phys. Rev. D 44, 1473 (1991) 59 (1999) 039901); J.A. Aguilar-Saavedra, B.M. Nobre, Rare top decays (Formula presented.) and CKM unitarity. Phys. Lett. B 553, 251 (2003); F. del Aguila, J.A. Aguilar-Saavedra, R. Miquel, Constraints on top couplings in models with exotic quarks. Phys. Rev. Lett. 82, 1628 (1999); J.A. Aguilar-Saavedra, Effects of mixing with quark singlets. Phys. Rev. D 67, 035003 (2003). (Erratum-ibid. D 69, 099901 (2004); Cheng, T.P., Sher, M., Mass matrix ansatz and flavor nonconservation in models with multiple Higgs doublets (1987) Phys. Rev. D, 35, p. 3484
  • Grzadkowski, B., Gunion, J.F., Krawczyk, P., Neutral current flavor changing decays for the Z boson and the top quark in two Higgs doublet models (1991) Phys. Lett. B, 268, p. 106
  • M.E. Luke, M.J. Savage, Flavor changing neutral currents in the Higgs sector and rare top decays. Phys. Lett. B 307, 387 (1993); D. Atwood, L. Reina, A. Soni, Probing flavor changing top-charm-scalar interactions in (Formula presented.) collisions. Phys. Rev. D 53, 1199 (1996); D. Atwood, L. Reina, A. Soni, Phenomenology of two Higgs doublet models with flavor changing neutral currents. Phys. Rev. D 55, 3156 (1997); S. Bejar, J. Guasch, J. Sola, Loop induced flavor changing neutral decays of the top quark in a general two-Higgs-doublet model. Nucl. Phys. B 600, 21 (2001); C.S. Li, R.J. Oakes, J.M. Yang, Rare decay of the top quark in the minimal supersymmetric model. Phys. Rev. D 49, 293 (1994). 56, 3156 (1997); G.M. de Divitiis, R. Petronzio, L. Silvestrini, Flavour changing top decays in supersymmetric extensions of the standard model. Nucl. Phys. B 504, 45 (1997); J.L. Lopez, D.V. Nanopoulos, R. Rangarajan, New supersymmetric contributions to (Formula presented.). Phys. Rev. D 56, 3100 (1997); J. Guasch, J. Sola, FCNC top quark decays: A door to SUSY physics in high luminosity colliders? Nucl. Phys. B 562, 3 (1999); D. Delepine, S. Khalil, Top flavour violating decays in general supersymmetric models. Phys. Lett. B 599, 62 (2004); J.J. Liu et al., (Formula presented.) via SUSY FCNC couplings in the unconstrained MSSM. Phys. Lett. B 599, 92 (2004); J.J. Cao et al., SUSY-induced FCNC top-quark processes at the Large Hadron Collider. Phys. Rev. D 75, 075021 (2007); J.M. Yang, B.-L. Young, X. Zhang, Flavor-changing top quark decays in R-parity violating SUSY. Phys. Rev. D 58, 055001 (1998); G. Eilam et al., Top quark rare decay (Formula presented.) in R-parity-violating SUSY. Phys. Lett. B 510, 227 (2001); Diaz-Cruz, J., Flavor-changing radiative decay of the t quark (1990) Phys. Rev. D, 41, p. 891
  • A. Arhrib, W.-S. Hou, Flavor changing neutral currents involving heavy quarks with four generations. JHEP 0607, 009 (2006); Branco, G., Rebelo, M., New physics in the flavour sector in the presence of flavour changing neutral currents PoS(Corfu2012) 024 (2013). arXiv, p. 4639
  • G. Lu et al., The rare top quark decays (Formula presented.) in the topcolor-assisted technicolor model. Phys. Rev. D 68, 015002 (2003); Aguilar-Saavedra, J., Top flavor-changing neutral interactions: theoretical expectations and experimental detection (2004) Acta Phys. Polon. B, 35, p. 2695. , arXiv:hep-ph/0409342
  • F. Larios, R. Martinez, M. Perez, New physics effects in the flavor-changing neutral couplings of the top quark. Int. J. Mod. Phys. A 21, 3473–3494 (2006); Buchmüller, W., Wyler, D., Effective lagrangian analysis of new interactions and flavour conservation (1986) Nucl. Phys. B, 268, p. 621
  • P. Ferreira, R. Santos, Strong flavor changing effective operator contributions to single top quark production. Phys. Rev. D 73, 054025 (2006); R. Coimbra et al., MEtop - a generator for single top production via FCNC interactions. Eur. Phys. J. C 72, 2222 (2012); Z.E.U.S. Collaboration, H. Abramowicz et al., Search for single-top production in ep collisions at HERA. Phys. Lett. B 708, 27 (2012); (2012) Phys. Lett. B, , ATLAS Collaboration, Search for FCNC single top-quark production at (Formula presented.) with the ATLAS detector. 712, 351
  • C.M.S. Collaboration, Search for flavor-changing neutral currents in top-quark decays (Formula presented.) in pp collisions (Formula presented.) TeV. Phys. Rev. Lett. 112, 171802 (2014); Search for top quark decays (Formula presented.) with (Formula presented.) using the ATLAS detector JHEP 1406, 008 (2014). doi:10.1007/JHEP06(2014)008. arXiv, 1403, p. 6293
  • The ATLAS experiment at the CERN Large Hadron Collider (2008) JINST, 3, p. S08003
  • Eur. Phys. J. C 72, 1849 (2012). doi:10.1140/epjc/s10052-011-1849-1 (2010) arXiv:1110.1530
  • ATLAS Collaboration, Performance of the ATLAS muon trigger in (Formula presented.). Eur. Phys. J. C 75, 120 (2015); Lai, H.-L., New parton distributions for collider physics. Phys. Rev D 82, 074024 (2010). doi:10.1103/PhysRevD.82.074024. arXiv, 1007, p. 2241
  • S. Frixione, P. Nason, C. Oleari, Matching NLO QCD computations with Parton Shower simulations: the POWHEG method. JHEP 0711, 070 (2007); S. Frixione, P. Nason, B.R. Webber, Matching NLO QCD and parton showers in heavy flavor production. JHEP 0308, 007 (2003); R. Frederix, E. Re, P. Torrielli, Single-top (Formula presented.) -channel hadroproduction in the four-flavour scheme with POWHEG and aMC@NLO. JHEP 1209, 130 (2012); S. Alioli et al., NLO single-top production matched with shower in POWHEG: (Formula presented.) -channel contributions. JHEP 0909, 111 (2009); E. Re, Single-top (Formula presented.) -channel production matched with parton showers using the POWHEG method. Eur. Phys. J. C 71, 1547 (2011); T. Sjostrand, S. Mrenna, P.Z. Skands, PYTHIA 6.4 Physics and Manual. JHEP 05, 026 (2006); P.Z. Skands, Tuning Monte Carlo generators: the Perugia tunes. Phys. Rev. D 82, 074018 (2010); T. Gleisberg et al., Event generation with SHERPA 1.1, JHEP 0902, 007 (2009); S. Hoeche et al., QCD matrix elements and truncated showers. JHEP 0905, 053 (2009); M.L. Mangano et al., ALPGEN, a generator for hard multiparton processes in hadronic collisions. JHEP 0307, 001 (2003); J. Pumplin et al., New generation of parton distributions with uncertainties from global QCD analysis. JHEP 0207, 012 (2002); G. Corcella et al., HERWIG 6: an event generator for hadron emission reactions with interfering gluons (including supersymmetric processes). JHEP 0101, 010 (2001); J. Butterworth, J.R. Forshaw, M. Seymour, Multiparton interactions in photoproduction at HERA. Z. Phys. C 72, 637–646 (1996); New ATLAS event generator tunes to 2010 data (2011) ATL-PHYS-PUB-2011-008, , http://cds.cern.ch/record/1345343
  • ATLAS Collaboration, The ATLAS simulation infrastructure. Eur. Phys. J. C 70, 823 (2010); Agostinelli, S., GEANT4: a simulation toolkit (2003) Nucl. Instrum. Meth. A, 506, p. 250
  • LHC proton–proton collision data. Eur. Phys. J. C 72, 1909 (2012). doi:10.1140/epjc/s10052-012-1909-1 (2010) arXiv:1110.3174 [hep-ex]
  • LHC proton–proton collision data. Eur. Phys. J. C 74, 3130 (2014). doi:10.1140/epjc/s10052-014-3130-x (2012) arXiv:1407.3935 [hep-ex]
  • Rehermann, K., Tweedie, B., Efficient identification of boosted semileptonic top quarks at the LHC (2011) JHEP, 1103, p. 059. , arXiv:1007.2221 [hep-ph]
  • Cacciari, M., Salam, G.P., Soyez, G., The anti- (Formula presented.) jet clustering algorithm (2008) JHEP, 804, p. 063. , arXiv:0802.1189 [hep-ph]
  • Calorimeter clustering algorithms: description and performance (2008) ATL-LARG-PUB-2008-002, , http://cds.cern.ch/record/1099735
  • ATLAS Collaboration, Jet energy measurement and its systematic uncertainty in proton–proton collisions at (Formula presented.) with the ATLAS detector. Eur. Phys. J. C 75, 17 (2015); Commissioning of the ATLAS high performance (Formula presented.) tagging algorithms in the 7 TeV collision data (2011) ATLAS-CONF-2011-102, , http://cdsweb.cern.ch/record/1369219
  • Calibration of the performance of (Formula presented.) -tagging for (Formula presented.) and light-flavour jets in the 2012 ATLAS data (2014) ATLAS-CONF-2014-046, , http://cdsweb.cern.ch/record/1741020
  • Calibration of (Formula presented.) -tagging using dileptonic top pair events in a combinatorial likelihood approach with the ATLAS experiment (2014) ATLAS-CONF-2014-004, , http://cdsweb.cern.ch/record/1664335
  • ATLAS Collaboration, Performance of missing transverse momentum reconstruction in proton–proton collisions at (Formula presented.) with ATLAS. Eur. Phys. J. C 72, 1844 (2012); Kidonakis, N., Next-to-next-to-leading-order collinear and soft gluon corrections for (Formula presented.) -channel single top quark production (2011) Phys. Rev. D, 83, p. 091503. , arXiv:1103.2792 [hep-ph]
  • Kidonakis, N., Two-loop soft anomalous dimensions for single top quark associated production with a (Formula presented.) or (Formula presented.) (2010) Phys. Rev. D, 82, p. 054018. , arXiv:1005.4451 [hep-ph]
  • Kidonakis, N., NNLL resummation for (Formula presented.) -channel single top quark production (2010) Phys. Rev. D, 81, p. 054028. , arXiv:1001.5034 [hep-ph]
  • M. Cacciari et al., Top-pair production at hadron colliders with next-to-next-to-leading logarithmic soft-gluon resummation. Phys. Lett. B 710, 612-622 (2012); Bärnreuther, P., Czakon, M., Mitov, A., Percent level precision physics at the Tevatron: first genuine NNLO QCD corrections to (Formula presented.) (2012) Phys. Rev. Lett., 109, p. 132001. , arXiv:1204.5201 [hep-ph]
  • Czakon, M., Mitov, A., NNLO corrections to top-pair production at hadron colliders: the all-fermionic scattering channels (2012) JHEP, 1212, p. 054. , arXiv:1207.0236 [hep-ph]
  • Czakon, M., Mitov, A., NNLO corrections to top pair production at hadron colliders: the quark–gluon reaction (2013) JHEP, 1301, p. 080. , arXiv:1210.6832 [hep-ph]
  • Czakon, M., Fiedler, P., Mitov, A., the total top quark pair production cross-section at hadron colliders through (Formula presented.) (2013) Phys. Rev. Lett., 110, p. 252004. , arXiv:1303.6254 [hep-ph]
  • Czakon, M., Mitov, A., Top++: a program for the calculation of the top-pair cross-section at hadron colliders (2014) Comput. Phys. Commun., 185, p. 2930. , arXiv:1112.5675 [hep-ph]
  • M. Botje et al., The PDF4LHC Working Group interim recommendations (2011); A. Martin et al., Parton distributions for the LHC. Eur. Phys. J. C 63, 189–285 (2009); A. Martin et al., Uncertainties on (Formula presented.) in global PDF analyses and implications for predicted hadronic cross sections. Eur. Phys. J. C 64, 653–680 (2009); Gao, J., The CT10 NNLO global analysis of QCD (2014) Phys. Rev. D, 89, p. 033009. , arXiv:1302.6246 [hep-ph]
  • R.D. Ball et al., Parton distributions with LHC data. Nucl. Phys. B 867, 244–289 (2013); K. Melnikov, F. Petriello, Electroweak gauge boson production at hadron colliders through (Formula presented.). Phys. Rev. D 74, 114017 (2006); Gavin, R., FEWZ 2.0: FEWZ 2.0: a code for hadronic (Formula presented.) production at next-to-next-to-leading order. Comput. Phys Commun. 182, 2388 (2011). doi:10.1016/j.cpc.2011.06.008. arXiv, 1011, p. 3540
  • J.M. Campbell, R. Ellis, MCFM for the Tevatron and the LHC. Nucl. Phys. Proc. Suppl. 205–206, 10–15 (2010); ATLAS Collaboration, Estimation of non-prompt and fake lepton backgrounds in final states with top quarks produced in proton–proton collisions at (Formula presented.) with the ATLAS detector. ATLAS-CONF-2014-058 (2014); Feindt, M., Kerzel, U., The NeuroBayes neural network package (2006) Nucl. Instrum. Meth. A, 559, p. 190
  • ATLAS Collaboration, Comprehensive measurements of (Formula presented.) -channel single top quark production cross section at (Formula presented.) TeV with the ATLAS detector. Phys. Rev. D 90, 112006 (2014); ATLAS Collaboration, Measurement of the (Formula presented.) -channel single top quark production cross section at (Formula presented.) with the ATLAS detector. Phys. Lett. B 717, 330 (2012); ATLAS Collaboration, Electron and photon energy calibration with the ATLAS detector using LHC Run 1 data. Eur. Phys. J. C 74, 3071 (2014); ATLAS Collaboration, Measurement of (Formula presented.) production with a veto on additional central jet activity in (Formula presented.) collisions at (Formula presented.) TeV using the ATLAS detector. Eur. Phys. J. C 72, 2043 (2012); ATLAS Collaboration, Improved luminosity determination in (Formula presented.) collisions using the ATLAS detector at the LHC. Eur. Phys. J. C 73, 2518 (2013); Read, A.L., Presentation of search results: the CL (Formula presented.) technique (2002) J. Phys. G, 28, p. 2693
  • Gao, J., Search for anomalous top quark production at the early LHC (2011) Phys. Rev. Lett., 107, p. 092002. , arXiv:1104.4945 [hep-ph]
  • Liu, J.J., Next-to-leading order QCD corrections to the direct top quark production via model-independent FCNC couplings at hadron colliders (2005) Phys. Rev. D, 72, p. 074018. , arXiv:hep-ph/0508016
  • Zhang, J.J., Next-to-leading order QCD corrections to the top quark decay via model-independent FCNC couplings (2009) Phys. Rev. Lett., 102, p. 072001. , arXiv:0810.3889 [hep-ph]

Citas:

---------- APA ----------
(2016) . Search for single top-quark production via flavour-changing neutral currents at 8 TeV with the ATLAS detector. European Physical Journal C, 76(2), 1-30.
http://dx.doi.org/10.1140/epjc/s10052-016-3876-4
---------- CHICAGO ----------
Aad, G. "Search for single top-quark production via flavour-changing neutral currents at 8 TeV with the ATLAS detector" . European Physical Journal C 76, no. 2 (2016) : 1-30.
http://dx.doi.org/10.1140/epjc/s10052-016-3876-4
---------- MLA ----------
Aad, G. "Search for single top-quark production via flavour-changing neutral currents at 8 TeV with the ATLAS detector" . European Physical Journal C, vol. 76, no. 2, 2016, pp. 1-30.
http://dx.doi.org/10.1140/epjc/s10052-016-3876-4
---------- VANCOUVER ----------
Aad, G. Search for single top-quark production via flavour-changing neutral currents at 8 TeV with the ATLAS detector. Eur. Phys. J. C. 2016;76(2):1-30.
http://dx.doi.org/10.1140/epjc/s10052-016-3876-4