A search for neutral Higgs bosons of the minimal supersymmetric standard model (MSSM) and for a heavneutral [Formula: see text] boson is performed using a data sample corresponding to an integrated luminosity of 3.2 fb[Formula: see text] from proton-proton collisions at [Formula: see text] [Formula: see text] recorded by the ATLAS detector at the LHC. The heavy resonance is assumed to decay to a [Formula: see text] pair with at least one [Formula: see text] lepton decaying to final states with hadrons and a neutrino. The search is performed in the mass range of 0.2-1.2 [Formula: see text] for the MSSM neutral Higgs bosons and 0.5-2.5 [Formula: see text] for the heavy neutral [Formula: see text] boson. The data are in good agreement with the background predicted by the Standard Model. The results are interpreted in MSSM and [Formula: see text] benchmark scenarios. The most stringent constraints on the MSSM [Formula: see text]-[Formula: see text] space exclude at 95 % confidence level (CL) [Formula: see text] for [Formula: see text] [Formula: see text] in the [Formula: see text] MSSM scenario. For the Sequential Standard Model, a [Formula: see text] mass up to 1.90 [Formula: see text] is excluded at 95 % CL and masses up to 1.82-2.17 [Formula: see text] are excluded for a [Formula: see text] of the strong flavour model.

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• časopisecké články MeSH

Combined analyses of the Higgs boson production and decay rates as well as its coupling strengths to vector bosons and fermions are presented. The combinations include the results of the analyses of the [Formula: see text] and [Formula: see text] decay modes, and the constraints on the associated production with a pair of top quarks and on the off-shell coupling strengths of the Higgs boson. The results are based on the LHC proton-proton collision datasets, with integrated luminosities of up to 4.7 [Formula: see text] at [Formula: see text] TeV and 20.3 [Formula: see text] at [Formula: see text] TeV, recorded by the ATLAS detector in 2011 and 2012. Combining all production modes and decay channels, the measured signal yield, normalised to the Standard Model expectation, is [Formula: see text]. The observed Higgs boson production and decay rates are interpreted in a leading-order coupling framework, exploring a wide range of benchmark coupling models both with and without assumptions on the Higgs boson width and on the Standard Model particle content in loop processes. The data are found to be compatible with the Standard Model expectations for a Higgs boson at a mass of 125.36 GeV for all models considered.

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• časopisecké články MeSH

A search for Higgs boson pair production [Formula: see text] is performed with 19.5 fb[Formula: see text] of proton-proton collision data at [Formula: see text] TeV, which were recorded by the ATLAS detector at the Large Hadron Collider in 2012. The decay products of each Higgs boson are reconstructed as a high-momentum [Formula: see text] system with either a pair of small-radius jets or a single large-radius jet, the latter exploiting jet substructure techniques and associated b-tagged track-jets. No evidence for resonant or non-resonant Higgs boson pair production is observed. The data are interpreted in the context of the Randall-Sundrum model with a warped extra dimension as well as the two-Higgs-doublet model. An upper limit on the cross-section for [Formula: see text] of 3.2 (2.3) fb is set for a Kaluza-Klein graviton [Formula: see text] mass of 1.0 (1.5) TeV, at the 95 % confidence level. The search for non-resonant Standard Model hh production sets an observed 95 % confidence level upper limit on the production cross-section [Formula: see text] of 202 fb, compared to a Standard Model prediction of [Formula: see text] fb.

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• časopisecké články MeSH