Projects per year
Abstract
A search for the Standard Model Higgs boson produced in association with a top-quark pair, tt¯H, is presented. The analysis uses 20.3 fb−1 of pp collision data at s√=8TeV, collected with the ATLAS detector at the Large Hadron Collider during 2012. The search is designed for the H→bb¯ decay mode and uses events containing one or two electrons or muons. In order to improve the sensitivity of the search, events are categorised according to their jet and b-tagged jet multiplicities. A neural network is used to discriminate between signal and background events, the latter being dominated by tt¯+jets production. In the single-lepton channel, variables calculated using a matrix element method are included as inputs to the neural network to improve discrimination of the irreducible tt¯+bb¯ background. No significant excess of events above the background expectation is found and an observed (expected) limit of 3.4 (2.2) times the Standard Model cross section is obtained at 95 % confidence level. The ratio of the measured tt¯H signal cross section to the Standard Model expectation is found to be μ=1.5±1.1 assuming a Higgs boson mass of 125GeV.
Original language | English |
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Article number | 349 |
Pages (from-to) | 1-50 |
Number of pages | 50 |
Journal | European Physical Journal C: Particles and Fields |
Volume | 75 |
DOIs | |
Publication status | Published - 29 Jul 2015 |
Projects
- 4 Finished
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Observation of the Higgs production mode in the ttH channel at ATLAS Marie Curie Fellow – Dr Michele Faucci Giannelli
Teixeira-Dias, P. (PI)
1/01/14 → 31/12/15
Project: Research
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GridPP4 Tranche-2 LondonGrid RHUL h/w grant
Teixeira-Dias, P. (PI)
Science and Technology Facilities Council
1/11/13 → 31/03/14
Project: Research
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Particle Physics STFC Consolidated Grant 2012
Cowan, G. (PI), Teixeira-Dias, P. (CoI), Berry, T. (CoI), Boisvert, V. (CoI), Monroe, J. (CoI) & Nikkel, J. A. (CoI)
Science and Technology Facilities Council
1/10/12 → 30/09/16
Project: Research