TY - JOUR
T1 - Search for the Standard Model Higgs boson produced in association with top quarks and decaying into in collisions at with the ATLAS detector
AU - Aad, A.
AU - Abbott, B.
AU - Abdallah, J.
AU - Abdinov, O.
AU - Aben, R.
AU - Abolins, M.
AU - AbouZeid, O.S.
AU - Abramowicz, H.
AU - Abreu, H.
AU - Abreu, R.
AU - Dam, Mogens
AU - Hansen, Jørn Dines
AU - Hansen, Jørgen Beck
AU - Xella, Stefania
AU - Hansen, Peter Henrik
AU - Petersen, Troels Christian
AU - Galster, Gorm Aske Gram Krohn
AU - Thomsen, Lotte Ansgaard
AU - Mehlhase, Sascha
AU - Jørgensen, Morten Dam
AU - Pingel, Almut Maria
AU - Løvschall-Jensen, Ask Emil
AU - Alonso Diaz, Alejandro
AU - Monk, James William
AU - Pedersen, Lars Egholm
AU - Wiglesworth, Graig
PY - 2015/7/30
Y1 - 2015/7/30
N2 - A search for the Standard Model Higgs boson produced in association with a top-quark pair, ttH, is presented. 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 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 StandardModel cross section is obtained at 95% confidence level. The ratio of the measured ttH signal cross section to the StandardModel expectation is found to be µ = 1.5±1.1 assuming a Higgs boson mass of 125 GeV.
AB - A search for the Standard Model Higgs boson produced in association with a top-quark pair, ttH, is presented. 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 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 StandardModel cross section is obtained at 95% confidence level. The ratio of the measured ttH signal cross section to the StandardModel expectation is found to be µ = 1.5±1.1 assuming a Higgs boson mass of 125 GeV.
U2 - 10.1140/epjc/s10052-015-3543-1
DO - 10.1140/epjc/s10052-015-3543-1
M3 - Journal article
C2 - 26269691
SN - 1434-6044
VL - 75
JO - European Physical Journal C
JF - European Physical Journal C
IS - 7
M1 - 349
ER -