A search for the Standard Model Higgs boson produced in association with a top-quark pair, tt H¯ , is pre sented. The analysis uses 20.3 fb−1 of pp collision data at √s = 8 TeV, 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 dis criminate 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 dis crimination of the irreducible tt¯+bb¯ background. No signif icant 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 125 GeV

Search for the standard model higgs boson produced in association with top quarks and decaying into bb in pp collisions at √s = 8 TeV with the ATLAS detector / G. Aad, B.A.. - In: THE EUROPEAN PHYSICAL JOURNAL. C, PARTICLES AND FIELDS. - ISSN 1434-6044. - ELETTRONICO. - 75:(2015), pp. 349.1-349.50. [10.1140/epjc/s10052-015-3543-1]

Search for the standard model higgs boson produced in association with top quarks and decaying into bb in pp collisions at √s = 8 TeV with the ATLAS detector

A. Calandri;
2015

Abstract

A search for the Standard Model Higgs boson produced in association with a top-quark pair, tt H¯ , is pre sented. The analysis uses 20.3 fb−1 of pp collision data at √s = 8 TeV, 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 dis criminate 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 dis crimination of the irreducible tt¯+bb¯ background. No signif icant 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 125 GeV
2015
75
1
50
G. Aad, B. Abbott, J. Abdallah, O. Abdinov, R. Aben, M. Abolins, O. S. AbouZeid, H. Abramowicz, H. Abreu, R. Abreu, Y. Abulaiti, B. S. Acharya, L. Ada...espandi
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Utilizza questo identificatore per citare o creare un link a questa risorsa: https://hdl.handle.net/2158/1418442
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