TY  - JOUR
T1  - Search for a heavy Higgs boson decaying into a \(Z\) boson and another heavy Higgs boson in the \({llbb}\) final state in \({pp}\) collisions at root \(s\)=13 TeV with the ATLAS detector
JF  - Physics Letters B
N2  - A search for a heavy neutral Higgs boson, A, decaying into a Z boson and another heavy Higgs boson, H, is performed using a data sample corresponding to an integrated luminosity of 36.1 fb(-1) from proton-proton collisions at root s = 13 TeV recorded in 2015 and 2016 by the ATLAS detector at the Large Hadron Collider. The search considers the Z boson decaying to electrons or muons and the H boson into a pair of b-quarks. No evidence for the production of an A boson is found. Considering each production process separately, the 95% confidence-level upper limits on the pp -> A -> ZH production cross-section times the branching ratio H -> bb are in the range of 14-830 fb for the gluon-gluon fusion process and 26-570 fb for the b-associated process for the mass ranges 130-700 GeV of the H boson and 230-800 GeV of the A boson. The results are interpreted in the context of two-Higgs-doublet models. (C) 2018 Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Funded by SCOAP(3).
KW  - Hadron Colliders
KW  - Parton Distributions
KW  - MASS
Y1  - 2018
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-226098
VL  - 783
ER  - 
TY  - JOUR
T1  - Direct top-quark decay width measurement in the t(t)over-bar lepton+jets channel at root \(s\)=8 TeV with the ATLAS experiment
JF  - European Physical Journal C
N2  - This paper presents a direct measurement of the decay width of the top quark using t (t) over bar events in the lepton+jets final state. The data sample was collected by the ATLAS detector at the LHC in proton-proton collisions at a centre-of-mass energy of 8 TeV and corresponds to an integrated luminosity of 20.2 fb(-1). The decay width of the top quark is measured using a template fit to distributions of kinematic observables associated with the hadronically and semileptonically decaying top quarks. The result, Gamma(t) = 1.76 +/- 0.33 (stat.) (+0.79)(-0.68) (syst.) GeV for a top-quark mass of 172.5 GeV, is consistent with the prediction of the Standard Model.
KW  - Parton Distributions
KW  - Hadron Colliders
KW  - Pair Production
KW  - Cross-Section
KW  - pp Collisions
Y1  - 2018
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-226805
VL  - 78
IS  - 129
ER  - 
TY  - JOUR
T1  - Search for dark matter produced in association with bottom or top quarks in root s=13 TeV \({pp}\) collisions with the ATLAS detector
JF  - European Physical Journal C
N2  - A search for weakly interacting massive dark matter particles produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and missing transverse momentum are considered. The analysis uses 36.1 fb(-1) of proton proton collision data recorded by the ATLAS experiment at root s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are interpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour-neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross-section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour-charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements.
KW  - Production Cross-Section
KW  - Pair Prodution
KW  - Parton Distributions
KW  - Hadron Colliders
KW  - Measuring Masses
KW  - LHC
Y1  - 2018
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-225937
VL  - C 78
IS  - 18
ER  -