Please use this identifier to cite or link to this item:
https://hdl.handle.net/2440/115193
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Type: | Journal article |
Title: | Search for flavour-changing neutral current top quark decays t → Hq in pp collisions at √s=8 TeV with the ATLAS detector |
Other Titles: | Search for flavour-changing neutral current top quark decays t -> Hq in pp collisions at root s=8 TeV with the ATLAS detector |
Author: | The, A.C. Aad, G. Abbott, B. Abdallah, J. Abdinov, O. Aben, R. Abolins, M. AbouZeid, O. Abramowicz, H. Abreu, H. Abreu, R. Abulaiti, Y. Acharya, B. Adamczyk, L. Adams, D. Adelman, J. Adomeit, S. Adye, T. Affolder, A. Agatonovic-Jovin, T. et al. |
Citation: | The Journal of High Energy Physics, 2015; 2015(12):061-1-061-65 |
Publisher: | Springer |
Issue Date: | 2015 |
ISSN: | 1126-6708 1029-8479 |
Statement of Responsibility: | G. Aad ... P. Jackson … L. Lee … A. Petridis … N. Soni … M.J. White … et al. (ATLAS Collaboration) |
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 bb¯¯, 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 s√=8 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 tt¯→WbWb 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 |λ tcH | and |λ tuH | 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. |
Keywords: | Hadron-Hadron Scattering; Top Physics; Higgs Physics; FCNC Interactions |
Rights: | © The Author(s) 2015. This article is published under an open access license. Please check the 'Copyright Information' section for details of this license and what re-use is permitted. If your intended use exceeds what is permitted by the license or if you are unable to locate the licence and re-use information, please contact the Rights and Permissions team. |
DOI: | 10.1007/JHEP12(2015)061 |
Published version: | http://dx.doi.org/10.1007/jhep12(2015)061 |
Appears in Collections: | Aurora harvest 3 Physics publications |
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hdl_115193.pdf | Published version | 1.14 MB | Adobe PDF | View/Open |
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