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

ATLAS Collaboration

doi: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

ATLAS Collaboration

iThemba Labs
Department of Physics
University of South Africa
Cadi Ayyad University
Moroccan Foundation for Advanced Science Innovation and Research (MAScIR)
Dep Física and CEFITEC of Faculdade de Ciências e Tecnologia
NOVA University Lisbon
CERN
Aix-Marseille Université
University of Oklahoma
Academia Sinica - Institute of Physics
Azerbaijan National Academy of Sciences
University of Amsterdam
Michigan State University
University of Toronto
Tel Aviv University
Technion-Israel Institute of Technology
Stockholm University
Oskar Klein Centre
National Institute for Nuclear Physics
Abdus Salam International Centre for Theoretical Physics
King's College London
AGH University of Krakow
Brookhaven National Laboratory
Northern Illinois University
Ludwig Maximilian University of Munich
Rutherford Appleton Laboratory
University of Liverpool
University of Belgrade
Laboratório de Instrumentação e Física Experimental de Partículas
University of Granada
University of Bern
Boston University
Joint Institute for Nuclear Research
University of Rome Tor Vergata
Lund University
The University of Tokyo
P.N. Lebedev Physical Institute of the Russian Academy of Sciences
University of Bologna
University of Victoria BC
Université Grenoble Alpes
Instituto de Física La Plata
Horia Hulubei National Institute of Physics and Nuclear Engineering
National Technical University of Athens
The University of Chicago
Columbia University
University of Birmingham

Research output: Contribution to journal › Article › peer-review

115 Scopus citations

Abstract

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.

Original language	English
Article number	349
Pages (from-to)	1-50
Number of pages	50
Journal	European Physical Journal C
Volume	75
Issue number	7
DOIs	https://doi.org/10.1140/epjc/s10052-015-3543-1
State	Published - Jul 30 2015

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@article{dc226afc207747c5820400f770139716,

title = "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",

abstract = "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.",

author = "\{ATLAS Collaboration\} and G. Aad and B. Abbott and J. Abdallah and O. Abdinov and R. Aben and M. Abolins and AbouZeid, \{O. S.\} and H. Abramowicz and H. Abreu and R. Abreu and Y. Abulaiti and Acharya, \{B. S.\} and L. Adamczyk and Adams, \{D. L.\} and J. Adelman and S. Adomeit and T. Adye and Affolder, \{A. A.\} and T. Agatonovic-Jovin and Aguilar-Saavedra, \{J. A.\} and M. Agustoni and Ahlen, \{S. P.\} and F. Ahmadov and G. Aielli and H. Akerstedt and {\AA}kesson, \{T. P.A.\} and G. Akimoto and Akimov, \{A. V.\} and Alberghi, \{G. L.\} and J. Albert and S. Albrand and \{Alconada Verzini\}, \{M. J.\} and M. Aleksa and Aleksandrov, \{I. N.\} and C. Alexa and G. Alexander and T. Alexopoulos and M. Alhroob and G. Alimonti and L. Alio and J. Alison and Alkire, \{S. P.\} and Allbrooke, \{B. M.M.\} and H. Arnold and \{Da Via\}, C. and V. Dao and J. Hobbs and J. Jia and G. Piacquadio and D. Tsybychev",

note = "Publisher Copyright: {\textcopyright} CERN for the benefit of the ATLAS collaboration 2015.",

year = "2015",

month = jul,

day = "30",

doi = "10.1140/epjc/s10052-015-3543-1",

language = "English",

volume = "75",

pages = "1--50",

journal = "European Physical Journal C",

issn = "1434-6044",

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TY - JOUR

T1 - 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

AU - ATLAS Collaboration

AU - Aad, G.

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 - Abulaiti, Y.

AU - Acharya, B. S.

AU - Adamczyk, L.

AU - Adams, D. L.

AU - Adelman, J.

AU - Adomeit, S.

AU - Adye, T.

AU - Affolder, A. A.

AU - Agatonovic-Jovin, T.

AU - Aguilar-Saavedra, J. A.

AU - Agustoni, M.

AU - Ahlen, S. P.

AU - Ahmadov, F.

AU - Aielli, G.

AU - Akerstedt, H.

AU - Åkesson, T. P.A.

AU - Akimoto, G.

AU - Akimov, A. V.

AU - Alberghi, G. L.

AU - Albert, J.

AU - Albrand, S.

AU - Alconada Verzini, M. J.

AU - Aleksa, M.

AU - Aleksandrov, I. N.

AU - Alexa, C.

AU - Alexander, G.

AU - Alexopoulos, T.

AU - Alhroob, M.

AU - Alimonti, G.

AU - Alio, L.

AU - Alison, J.

AU - Alkire, S. P.

AU - Allbrooke, B. M.M.

AU - Arnold, H.

AU - Da Via, C.

AU - Dao, V.

AU - Hobbs, J.

AU - Jia, J.

AU - Piacquadio, G.

AU - Tsybychev, D.

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.

UR - https://www.scopus.com/pages/publications/84938308942

U2 - 10.1140/epjc/s10052-015-3543-1

DO - 10.1140/epjc/s10052-015-3543-1

M3 - Article

AN - SCOPUS:84938308942

SN - 1434-6044

VL - 75

SP - 1

EP - 50

JO - European Physical Journal C

JF - European Physical Journal C

IS - 7

M1 - 349

ER -

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

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