Search for the associated production of the Higgs boson with a top quark pair in multilepton final states with the ATLAS detector

Allbrooke, B M M, Asquith, L, Cerri, A, Chavez Barajas, C A, De Santo, A, Salvatore, F, Santoyo Castillo, I, Suruliz, K, Sutton, M R, Vivarelli, I and The ATLAS Collaboration, et al. (2015) Search for the associated production of the Higgs boson with a top quark pair in multilepton final states with the ATLAS detector. Physics Letters B, 749. pp. 519-541. ISSN 0370-2693

[img] PDF (©2015 CERN for the benefit of the ATLAS Collaboration) - Published Version
Available under License Creative Commons Attribution.

Download (1MB)

Abstract

A search for the associated production of the Higgs boson with a top quark pair is performed in multilepton final states using 20.3 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s=8 TeV at the Large Hadron Collider. Five final states, targeting the decays H→WW⁎H→WW⁎, ττ, and ZZ⁎, are examined for the presence of the Standard Model (SM) Higgs boson: two same-charge light leptons (e or μ) without a hadronically decaying τ lepton; three light leptons; two same-charge light leptons with a hadronically decaying τ lepton; four light leptons; and one light lepton and two hadronically decaying τ leptons. No significant excess of events is observed above the background expectation. The best fit for the tt¯H production cross section, assuming a Higgs boson mass of 125 GeV, is 2.1 −1.2+1.4 times the SM expectation, and the observed (expected) upper limit at the 95% confidence level is 4.7 (2.4) times the SM rate. The p-value for compatibility with the background-only hypothesis is 1.8σ; the expectation in the presence of a Standard Model signal is 0.9σ.

Item Type: Article
Schools and Departments: School of Mathematical and Physical Sciences > Physics and Astronomy
Research Centres and Groups: Experimental Particle Physics Research Group
Subjects: Q Science > QC Physics
Depositing User: Billy Wichaidit
Date Deposited: 26 Apr 2017 09:34
Last Modified: 26 Apr 2017 10:03
URI: http://sro.sussex.ac.uk/id/eprint/67492

View download statistics for this item

📧 Request an update
Project NameSussex Project NumberFunderFunder Ref
ATLASG0275STFC-SCIENCE AND TECHNOLOGY FACILITIES COUNCILST/I006048/1