@article{OPUS4-22070, title = {Search for supersymmetry in events with four or more leptons in root s=13 TeV \({pp}\) collisions with ATLAS}, series = {Physical Review D}, volume = {98}, journal = {Physical Review D}, number = {3}, organization = {The ATLAS Collaboration}, doi = {10.1103/PhysRevD.98.032009}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-220705}, pages = {1-31}, year = {2018}, abstract = {Results from a search for supersymmetry in events with four or more charged leptons (electrons, muons and taus) are presented. The analysis uses a data sample corresponding to 36.1 fb(-1) of proton-proton collisions delivered by the Large Hadron Collider at root s = 13 TeV and recorded by the ATLAS detector. Four-lepton signal regions with up to two hadronically decaying taus are designed to target a range of supersymmetric scenarios that can be either enriched in or depleted of events involving the production and decay of a Z boson. Data yields are consistent with Standard Model expectations and results are used to set upper limits on the event yields from processes beyond the Standard Model. Exclusion limits are set at the 95\% confidence level in simplified models of general gauge mediated supersymmetry, where Higgsino masses are excluded up to 295 GeV. In R-parity-violating simplified models with decays of the lightest supersymmetric particle to charged leptons, lower limits of 1.46, 1.06, and 2.25 TeV are placed on wino, slepton and gluino masses, respectively.}, language = {en} } @article{OPUS4-22087, title = {Measurement of differential cross sections and W\(^+\)/W\(^-\) cross-section ratios for W boson production in association with jets at root s=8 TeV with the ATLAS detector}, series = {Journal of High Energy Physics}, volume = {77}, journal = {Journal of High Energy Physics}, number = {5}, organization = {The ATLAS collaboration}, doi = {10.1007/JHEP05(2018)077}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-220872}, pages = {1-61}, year = {2018}, abstract = {This paper presents a measurement of the W boson production cross section and the W+/W- cross-section ratio, both in association with jets, in proton-proton collisions at root s = 8 TeV with the ATLAS experiment at the Large Hadron Collider. The measurement is performed in final states containing one electron and missing transverse momentum using data corresponding to an integrated luminosity of 20.2 fb(-1). Differential cross sections for events with at least one or two jets are presented for a range of observables, including jet transverse momenta and rapidities, the scalar sum of transverse momenta of the visible particles and the missing transverse momentum in the event, and the transverse momentum of the W boson. For a subset of the observables, the differential cross sections of positively and negatively charged W bosons are measured separately. In the cross-section ratio of W+/W- the dominant systematic uncertainties cancel out, improving the measurement precision by up to a factor of nine. The observables and ratios selected for this paper provide valuable input for the up quark, down quark, and gluon parton distribution functions of the proton.}, language = {en} } @article{OPUS4-22083, title = {Search for squarks and gluinos in final states with jets and missing transverse momentum using 36 fb\(^{-1}\) of root s=13 TeV \({pp}\) collision data with the ATLAS detector}, series = {Physical Review D}, volume = {97}, journal = {Physical Review D}, number = {11}, organization = {The ATLAS Collaboration}, doi = {10.1103/PhysRevD.97.112001}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-220835}, pages = {1-47}, year = {2018}, abstract = {A search for the supersymmetric partners of quarks and gluons (squarks and gluinos) in final states containing hadronic jets and missing transverse momentum, but no electrons or muons, is presented. The data used in this search were recorded in 2015 and 2016 by the ATLAS experiment in root s = 13 TeV proton-proton collisions at the Large Hadron Collider, corresponding to an integrated luminosity of 36.1 fb(-1). The results are interpreted in the context of various models where squarks and gluinos are pair produced and the neutralino is the lightest supersymmetric particle. An exclusion limit at the 95\% confidence level on the mass of the gluino is set at 2.03 TeV for a simplified model incorporating only a gluino and the lightest neutralino, assuming the lightest neutralino is massless. For a simplified model involving the strong production of mass-degenerate first-and second-generation squarks, squark masses below 1.55 TeVare excluded if the lightest neutralino is massless. These limits substantially extend the region of supersymmetric parameter space previously excluded by searches with the ATLAS detector.}, language = {en} } @article{OPUS4-22586, title = {Search for \(B\) - \(L\) \(R\)-parity-violating top squarks in root s=13 TeV \({pp}\) collisions with the ATLAS experiment}, series = {Physical Review D}, volume = {97}, journal = {Physical Review D}, number = {3}, organization = {The ATLAS Collaboration}, doi = {10.1103/PhysRevD.97.032003}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-225863}, pages = {1-42}, year = {2018}, abstract = {A search is presented for the direct pair production of the stop, the supersymmetric partner of the top quark, that decays through an R-parity-violating coupling to a final state with two leptons and two jets, at least one of which is identified as a b-jet. The data set corresponds to an integrated luminosity of 36.1 fb(-1) of proton-proton collisions at a center-of-mass energy of root s = 13 TeV, collected in 2015 and 2016 by the ATLAS detector at the LHC. No significant excess is observed over the Standard Model background, and exclusion limits are set on stop pair production at a 95\% confidence level. Lower limits on the stop mass are set between 600 GeV and 1.5 TeV for branching ratios above 10\% for decays to an electron or muon and a b-quark.}, language = {en} } @article{OPUS4-22545, title = {Search for long-lived, massive particles in events with displaced vertices and missing transverse momentum in root S=13 TeV \({pp}\) collisions with the ATLAS detector}, series = {Physical Review D}, volume = {97}, journal = {Physical Review D}, number = {5}, organization = {The ATLAS Collaboration}, doi = {10.1103/PhysRevD.97.052012}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-225450}, pages = {1-29}, year = {2018}, abstract = {A search for long-lived, massive particles predicted by many theories beyond the Standard Model is presented. The search targets final states with large missing transverse momentum and at least one highmass displaced vertex with five or more tracks, and uses 32.8 fb(-1) of root s = 13 TeV pp collision data collected by the ATLAS detector at the LHC. The observed yield is consistent with the expected background. The results are used to extract 95\% C.L. exclusion limits on the production of long-lived gluinos with masses up to 2.37 TeV and lifetimes of O(10(-2)) - O(10) ns in a simplified model inspired by split supersymmetry.}, language = {en} } @article{OPUS4-22074, title = {Search for supersymmetry in final states with missing transverse momentum and multiple b-jets in proton-proton collisions at root s=13 TeV with the ATLAS detector}, series = {Journal of High Energy Physics}, volume = {107}, journal = {Journal of High Energy Physics}, number = {6}, organization = {The ATLAS collaboration}, doi = {10.1007/JHEP06(2018)107}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-220748}, pages = {1-55}, year = {2018}, abstract = {A search for supersymmetry involving the pair production of gluinos decaying via third-generation squarks into the lightest neutralino ((chi) over tilde (0)(1)) is reported. It uses LHC proton-proton collision data at a centre-of-mass energy root s = 13TeV with an integrated luminosity of 36.1 fb(-1) collected with the ATLAS detector in 2015 and 2016. The search is performed in events containing large missing transverse momentum and several energetic jets, at least three of which must be identified as originating from b-quarks. To increase the sensitivity, the sample is divided into subsamples based on the presence or absence of electrons or muons. No excess is found above the predicted background. For (chi) over tilde (0)(1) masses below approximately 300 GeV, gluino masses of less than 1.97 (1.92) TeV are excluded at 95\% confidence level in simplified models involving the pair production of gluinos that decay via top (bottom) squarks. An interpretation of the limits in terms of the branching ratios of the gluinos into third-generation squarks is also provided. These results improve upon the exclusion limits obtained with the 3.2 fb(-1) of data collected in 2015.}, language = {en} } @article{OPUS4-22604, title = {Search for R-parity-violating supersymmetric particles in multi-jet final states produced in \({p-p}\) collisions at root \(s\)=13 TeV using the ATLAS detector at the LHC}, series = {Physics Letters B}, volume = {785}, journal = {Physics Letters B}, organization = {The ATLAS Collaboration}, doi = {10.1016/j.physletb.2018.08.021}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-226047}, pages = {136-158}, year = {2018}, abstract = {Results of a search for gluino pair production with subsequent R-parity-violating decays to quarks are presented. This search uses 36.1 fb(-1) of data collected by the ATLAS detector in proton-proton collisions with a centre-of-mass energy of root s = 13 TeV at the LHC. The analysis is performed using requirements on the number of jets and the number of jets tagged as containing a b-hadron as well as a topological observable formed by the scalar sum of masses of large-radius jets in the event. No significant excess above the expected Standard Model background is observed. Limits are set on the production of gluinos in models with the R-parity-violating decays of either the gluino itself (direct decay) or the neutralino produced in the R-parity-conserving gluino decay (cascade decay). In the gluino cascade decay model, gluino masses below 1850 GeV are excluded for 1000 GeV neutralino mass. For the gluino direct decay model, the 95\% confidence level upper limit on the cross section times branching ratio varies between 0.80 fb at m((g) over tilde) = 900 GeV and 0.011 fb at m((g) over tilde) = 1800 GeV. (c) 2018 The Author. Published by Elsevier B.V. This is an open access article under the CC BY license.}, language = {en} } @article{OPUS4-22560, title = {Search for the direct production of charginos and neutralinos in final states with tau leptons in root s=13 TeV pp collisions with the ATLAS detector}, series = {The European Physical Journal C}, volume = {78}, journal = {The European Physical Journal C}, number = {154}, organization = {The ATLAS Collaboration}, doi = {10.1140/epjc/s10052-018-5583-9}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-225602}, pages = {1-33}, year = {2018}, abstract = {A search for the direct production of charginos and neutralinos in final states with at least two hadronically decaying tau leptons is presented. The analysis uses a dataset of pp collisions corresponding to an integrated luminosity of 36.1 fb, recorded with the ATLAS detector at the Large Hadron Collider at a centre-of-mass energy of 13 TeV. No significant deviation from the expected Standard Model background is observed. Limits are derived in scenarios of pair production and of and production in simplified models where the neutralinos and charginos decay solely via intermediate left-handed staus and tau sneutrinos, and the mass of the state is set to be halfway between the masses of the and the (chi) over tilde (0.)(1) . Chargino masses up to 630 GeV are excluded at 95\% confidence level in the scenario of direct production of for a massless (chi) over tilde (0.)(1). Common and masses up to 760 GeV are excluded in the case of production of and assuming a massless . Exclusion limits for additional benchmark scenarios with large and small mass-splitting between the and the are also studied by varying the mass between the masses of the and the (chi) over tilde (0.)(1)}, language = {en} } @article{OPUS4-22542, title = {Search for heavy \({ZZ}\) resonances in the l\(^+\)l\(^-\)l\(^+\)l\(^-\) and l\(^+\)l\(^-\) nu(nu)over-bar final states using proton-proton collisions at root s=13 TeV with the ATLAS detector}, series = {The European Physical Journal C}, volume = {78}, journal = {The European Physical Journal C}, number = {293}, organization = {The ATLAS Collaboration}, doi = {10.1140/epjc/s10052-018-5686-3}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-225421}, pages = {1-34}, year = {2018}, abstract = {A search for heavy resonances decaying into a pair of Z bosons leading to l(+) l(-) l(+) l(-) and l(+) l(-) nu(nu) over bar final states, where l stands for either an electron or a muon, is presented. The search uses proton-proton collision data at a centre-of-mass energy of 13 TeV corresponding to an integrated luminosity of 36.1 fb(-1) collected with the ATLAS detector during 2015 and 2016 at the Large Hadron Collider. Different mass ranges for the hypothetical resonances are considered, depending on the final state and model. The different ranges span between 200 and 2000 GeV. The results are interpreted as upper limits on the production cross section of a spin-0 or spin-2 resonance. The upper limits for the spin-0 resonance are translated to exclusion contours in the context of Type-I and Type-II two-Higgs-doublet models, while those for the spin-2 resonance are used to constrain the Randall-Sundrum model with an extra dimension giving rise to spin-2 graviton excitations.}, language = {en} } @article{OPUS4-22610, title = {Search for new phenomena using the invariant mass distribution of same-flavour opposite-sign dilepton pairs in events with missing transverse momentum in root \(s\)=13 TeV \(pp\) collisions with the ATLAS detector}, series = {European Physical Journal C}, volume = {78}, journal = {European Physical Journal C}, organization = {The ATLAS Collaboration}, doi = {10.1140/epjc/s10052-018-6081-9}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-226109}, pages = {1-38}, year = {2018}, abstract = {A search for new phenomena in final states containing an e(+)e(-) or m(+)m(-) pair, jets, and large missing transverse momentum is presented. This analysis makes use of proton-proton collision data with an integrated luminosity of 36.1 fb(-1), collected during 2015 and 2016 at a centre of-mass energy Os = 13 TeV with the ATLAS detector at the Large Hadron Collider. The search targets the pair production of supersymmetric coloured particles (squarks or gluinos) and their decays into final states containing an e(+)e(-) or m(+)m(-) pair and the lightest neutralino ((c) over tilde (0)(1)) via one of two next-to-lightest neutralino ((c) over tilde (0)(2)) decay mechanisms: (c) over tilde (0)(2) Z (c) over tilde (0)(1), where the Z boson decays leptonically leading to a peak in the dilepton invariant mass distribution around the Z boson mass; and (c) over tilde (0)(2) l(+)1(-) (c) over tilde (0)(1) with no intermediate l(+)l(-) resonance, yielding a kinematic endpoint in the dilepton invariant mass spectrum. The data are found to be consistent with the Standard Model expectation. Results are interpreted using simplified models, and exclude gluinos and squarks with masses as large as 1.85 and 1.3 TeV at 95\% confidence level, respectively.}, language = {en} } @article{OPUS4-22675, title = {Search for supersymmetry in final states with charm jets and missing transverse momentum in 13 TeV \(pp\) collisions with the ATLAS detector}, series = {Journal of High Energy Physics}, volume = {09}, journal = {Journal of High Energy Physics}, organization = {The ATLAS Collaboration}, doi = {10.1007/JHEP09(2018)050}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-226752}, pages = {1-43}, year = {2018}, abstract = {A search for supersymmetric partners of top quarks decaying as (t) over tilde (1) -> c (chi) over tilde (0)(1)and supersymmetric partners of charm quarks decaying as (c) over tilde (1) -> c (chi) over tilde (0)(1) where (chi) over tilde (0)(1) is the lightest neutralino, is presented. The search uses 36.1 fb(-1) pp collision data at a centre-of-mass energy of 13 TeV collected by the ATLAS experiment at the Large Hadron Collider and is performed in final states with jets identified as containing charm hadrons. Assuming a 100\% branching ratio to c (chi) over tilde (0)(1), top and charm squarks with masses up to 850 GeV are excluded at 95\% confidence level for a massless lightest neutralino. For m (t) over tilde (1,(c) over tilde1) - m((chi) over tilde 10)< 100 GeV, top and charm squark masses up to 500 GeV are excluded.}, language = {en} } @article{OPUS4-34679, title = {Constraints on off-shell Higgs boson production and the Higgs boson total width in \(ZZ\) → 4l and \(ZZ\) → 2l2ν final states with the ATLAS detector}, series = {Physics Letters B}, volume = {786}, journal = {Physics Letters B}, organization = {The ATLAS Collaboration}, doi = {10.1016/j.physletb.2018.09.048}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-346791}, pages = {223-244}, year = {2018}, abstract = {A measurement of off-shell Higgs boson production in the ZZ -> 4l and ZZ -> 2l2v decay channels, where stands for either an electron or a muon, is performed using data from proton-proton collisions at a centre-of-mass energy of root s = 13 TeV. The data were collected by the ATLAS experiment in 2015 and 2016 at the Large Hadron Collider, and they correspond to an integrated luminosity of 36.1 fb(-1). An observed (expected) upper limit on the off-shell Higgs signal strength, defined as the event yield normalised to the Standard Model prediction, of 3.8 (3.4) is obtained at 95\% confidence level (CL). Assuming the ratio of the Higgs boson couplings to the Standard Model predictions is independent of the momentum transfer of the Higgs production mechanism considered in the analysis, a combination with the on-shell signal-strength measurements yields an observed (expected) 95\% CL upper limit on the Higgs boson total width of 14.4 (15.2) MeV.}, language = {en} } @article{OPUS4-22546, title = {A search for pair-produced resonances in four-jet final states at root s=13 TeV with the ATLAS detector}, series = {The European Physical Journal C}, volume = {78}, journal = {The European Physical Journal C}, number = {250}, organization = {The ATLAS Collaboration}, doi = {10.1140/epjc/s10052-018-5693-4}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-225465}, pages = {1-28}, year = {2018}, abstract = {A search for massive coloured resonances which are pair-produced and decay into two jets is presented. The analysis uses 36.7 fb(-1) of root s = 13 TeV pp collision data recorded by the ATLAS experiment at the LHC in 2015 and 2016. No significant deviation from the background prediction is observed. Results are interpreted in a SUSY simplified model where the lightest supersymmetric particle is the top squark, (t) over tilde, which decays promptly into two quarks through R-parity-violating couplings. Top squarks with masses in the range 100 GeV < m((T) over tilde) < 410 GeV are excluded at 95\% confidence level. If the decay is into a b-quark and a light quark, a dedicated selection requiring two b-tags is used to exclude masses in the ranges 100 GeV < m((t) over tilde) < 470 GeV and 480 GeV < m(<(t)over tilde>) < 610 GeV. Additional limits are set on the pair-production of massive colour-octet resonances.}, language = {en} } @article{OPUS4-22684, title = {Search for high-mass dilepton resonances using 139 fb\(^{-1}\) of \(pp\) collision data collected at root \(s\)=13 TeV with the ATLAS detector}, series = {Physics Letters B}, volume = {796}, journal = {Physics Letters B}, organization = {The ATLAS Collaboration}, doi = {10.1016/j.physletb.2019.07.016}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-226844}, pages = {68-87}, year = {2019}, abstract = {A search for high-mass dielectron and dimuon resonances in the mass range of 250 GeV to 6TeV is presented. The data were recorded by the ATLAS experiment in proton-proton collisions at a centre-ofmass energy of root s = 13 TeV during Run 2 of the Large Hadron Collider and correspond to an integrated luminosity of 139 fb(-1). A functional form is fitted to the dilepton invariant-mass distribution to model the contribution from background processes, and a generic signal shape is used to determine the significance of observed deviations from this background estimate. No significant deviation is observed and upper limits are placed at the 95\% confidence level on the fiducial cross-section times branching ratio for various resonance width hypotheses. The derived limits are shown to be applicable to spin-0, spin-1 and spin-2 signal hypotheses. For a set of benchmark models, the limits are converted into lower limits on the resonance mass and reach 4.5 TeV for the E-6-motivated Z(psi)' boson. Also presented are limits on Heavy Vector Triplet model couplings. (C) 2019 The Author. Published by Elsevier B.V.}, language = {en} } @article{OPUS4-22683, title = {Search for a heavy charged boson in events with a charged lepton and missing transverse momentum from \(pp\) collisions at √\(s\)=13 TeV with the ATLAS detector}, series = {Physical Review D}, volume = {100}, journal = {Physical Review D}, organization = {The ATLAS Collaboration}, doi = {10.1103/PhysRevD.100.052013}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-226835}, pages = {1-29}, year = {2019}, abstract = {A search for a heavy charged-boson resonance decaying into a charged lepton (electron or muon) and a neutrino is reported. A data sample of 139 fb(-1) of proton-proton collisions at root s = 13 TeV collected with the ATLAS detector at the LHC during 2015-2018 is used in the search. The observed transverse mass distribution computed from the lepton and missing transverse momenta is consistent with the distribution expected from the Standard Model, and upper limits on the cross section for pp -> W'-> lv are extracted (l = e or mu). These vary between 1.3 pb and 0.05 tb depending on the resonance mass in the range between 0.15 and 7.0 TeV at 95\% confidence level for the electron and muon channels combined. Gauge bosons with a mass below 6.0 and 5.1 TeV are excluded in the electron and muon channels, respectively, in a model with a resonance that has couplings to fermions identical to those of the Standard Model W boson. Cross-section limits are also provided for resonances with several fixed Gamma/m values in the range between 1\% and 15\%. Model-independent limits are derived in single-bin signal regions defined by a varying minimum transverse mass threshold. The resulting visible cross-section upper limits range between 4.6 (15) ph and 22 (22) ab as the threshold increases from 130 (110) GeV to 5.1 (5.1) TeV in the electron (muon) channel.}, language = {en} }