@article{OPUS4-22602, title = {Measurements of differential cross sections of top quark pair production in association with jets in pp collisions at root s=13 TeV using the ATLAS detector}, series = {Journal of High Energy Physics}, volume = {159}, journal = {Journal of High Energy Physics}, number = {10}, organization = {The ATLAS Collaboration}, doi = {10.1007/JHEP10(2018)159}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-226023}, pages = {1-57}, year = {2018}, abstract = {Measurements of di ff erential cross sections of top quark pair production in association with jets by the ATLAS experiment at the LHC are presented. The measurements are performed as functions of the top quark transverse momentum, the transverse momentum of the top quark-antitop quark system and the out-of-plane transverse momentum using data from pp collisions at p s = 13TeV collected by the ATLAS detector at the LHC in 2015 and corresponding to an integrated luminosity of 3.2 fb. The top quark pair events are selected in the lepton (electron or muon) + jets channel. The measured cross sections, which are compared to several predictions, allow a detailed study of top quark production.}, language = {en} } @article{OPUS4-22611, title = {Search for flavour-changing neutral current top-quark decays \(t\) -> \({qZ}\) in proton-proton collisions at root s=13 TeV with the ATLAS detector}, series = {Journal of High Energy Physics}, volume = {176}, journal = {Journal of High Energy Physics}, number = {7}, organization = {The ATLAS Collaboration}, doi = {10.1007/JHEP07(2018)176}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-226114}, pages = {1-40}, year = {2018}, abstract = {A search for flavour-changing neutral-current processes in top-quark decays is presented. Data collected with the ATLAS detector from proton-proton collisions at the Large Hadron Collider at a centre-of-mass energy of root s = 13TeV, corresponding to an integrated luminosity of 36.1 fb(-1), are analysed. The search is performed using top-quark pair events, with one top quark decaying through the t -> qZ (q = u, c) flavour-changing neutral-current channel, and the other through the dominant Standard Model mode t -> bW. Only Z boson decays into charged leptons and leptonic W boson decays are considered as signal. Consequently, the final-state topology is characterized by the presence of three isolated charged leptons (electrons or muons), at least two jets, one of the jets originating from a b-quark, and missing transverse momentum from the undetected neutrino. The data are consistent with Standard Model background contributions, and at 95\% confidence level the search sets observed (expected) upper limits of 1.7 x 10(-4) (2.4 x 10(-4)) on the t -> uZ branching ratio and 2.4 x 10(-4) (3.2 x 10(-4)) on the t -> cZ branching ratio, constituting the most stringent limits to date.}, language = {en} } @article{OPUS4-22615, title = {Measurement of the production cross section of three isolated photons in \({pp}\) collisions at root \(s\)=8 TeV using the ATLAS detector}, series = {Physics Letters B}, volume = {781}, journal = {Physics Letters B}, organization = {The ATLAS Collaboration}, doi = {10.1016/j.physletb.2018.03.057}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-226154}, pages = {55-76}, year = {2018}, abstract = {A measurement of the production of three isolated photons in proton-proton collisions at a centre-of-mass energy root s = 8 TeV is reported. The results are based on an integrated luminosity of 20.2 fb(-1) collected with the ATLAS detector at the LHC. The differential cross sections are measured as functions of the transverse energy of each photon, the difference in azimuthal angle and in pseudorapidity between pairs of photons, the invariant mass of pairs of photons, and the invariant mass of the triphoton system. A measurement of the inclusive fiducial cross section is also reported. Next-to-leading-order perturbative QCD predictions are compared to the cross-section measurements. The predictions underestimate the measurement of the inclusive fiducial cross section and the differential measurements at low photon transverse energies and invariant masses. They provide adequate descriptions of the measurements at high values of the photon transverse energies, invariant mass of pairs of photons, and invariant mass of the triphoton system. (C) 2018 The Author. Published by Elsevier B.V.}, language = {en} } @article{OPUS4-34784, title = {Measurement of differential cross sections of isolated-photon plus heavy-flavour jet production in \(pp\) collisions at √\(s\) = 8 TeV using the ATLAS detector}, series = {Physics Letters B}, volume = {776}, journal = {Physics Letters B}, organization = {The ATLAS Collaboration}, doi = {10.1016/j.physletb.2017.11.054}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-347841}, pages = {295-317}, year = {2018}, abstract = {This Letter presents the measurement of differential cross sections of isolated prompt photons produced in association with a b-jet or a c-jet. These final states provide sensitivity to the heavy-flavour content of the proton and aspects related to the modelling of heavy-flavour quarks in perturbative QCD. The measurement uses proton-proton collision data at a centre-of-mass energy of 8 TeV recorded by the ATLAS detector at the LHC in 2012 corresponding to an integrated luminosity of up to 20.2 fb-1 . The differential cross sections are measured for each jet flavour with respect to the transverse energy of the leading photon in two photon pseudorapidity regions: |η γ | < 1.37 and 1.56 < |η γ | < 2.37. The measurement covers photon transverse energies 25 < Eγ T < 400 GeV and 25 < Eγ T < 350 GeV respectively for the two |η γ | regions. For each jet flavour, the ratio of the cross sections in the two |η γ | regions is also measured. The measurement is corrected for detector effects and compared to leading-order and next- to-leading-order perturbative QCD calculations, based on various treatments and assumptions about the heavy-flavour content of the proton. Overall, the predictions agree well with the measurement, but some deviations are observed at high photon transverse energies. The total uncertainty in the measurement ranges between 13\% and 66\%, while the central γ + b measurement exhibits the smallest uncertainty, ranging from 13\% to 27\%, which is comparable to the precision of the theoretical predictions.}, language = {en} } @article{OPUS4-22601, title = {Search for pair production of Higgsinos in final states with at least three \(b\)-tagged jets in root \(s\)=13 TeV \(pp\) collisions using the ATLAS detector}, series = {Physical Review D}, volume = {98}, journal = {Physical Review D}, organization = {The ATLAS Collaboration}, doi = {10.1103/PhysRevD.98.092002}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-226010}, pages = {1-34}, year = {2018}, abstract = {A search for pair production of the supersymmetric partners of the Higgs boson (higgsinos (H) over tilde) in gaugemediated scenarios is reported. Each higgsino is assumed to decay to a Higgs boson and a gravitino. Two complementary analyses, targeting high- and low-mass signals, are performed to maximize sensitivity. The two analyses utilize LHC pp collision data at a center-of-mass energy root s = 13 TeV, the former with an integrated luminosity of 36.1 fb(-1) and the latter with 24.3 fb(-1), collected with the ATLAS detector in 2015 and 2016. The search is performed in events containing missing transverse momentum and several energetic jets, at least three of which must be identified as b-quark jets. No significant excess is found above the predicted background. Limits on the cross section are set as a function of the mass of the <(Hover tilde> in simplified models assuming production via mass-degenerate higgsinos decaying to a Higgs boson and a gravitino. Higgsinos with masses between 130 and 230 GeV and between 290 and 880 GeV are excluded at the 95\% confidence level. Interpretations of the limits in terms of the branching ratio of the higgsino to a Z boson or a Higgs boson are also presented, and a 45\% branching ratio to a Higgs boson is excluded for m(<(Hover tilde>) approximate to 400 GeV.}, language = {en} } @article{OPUS4-22607, title = {Search for heavy resonances decaying to a photon and a hadronically decaying \({Z/W/H}\) boson in \(pp\) collisions at root \(s\)=13 TeV with the ATLAS detector}, series = {Physical Review D}, volume = {98}, journal = {Physical Review D}, organization = {The ATLAS Collaboration}, doi = {10.1103/PhysRevD.98.032015}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-226079}, pages = {1-29}, year = {2018}, abstract = {Many extensions of the Standard Model predict new resonances decaying to a Z, W, or Higgs boson and a photon. This paper presents a search for such resonances produced in pp collisions at root s = 13 TeV using a data set with an integrated luminosity of 36.1 fb(-1) collected by the ATLAS detector at the LHC. The Z/W/H bosons are identified through their decays to hadrons. The data are found to be consistent with the Standard Model expectation in the entire investigated mass range. Upper limits are set on the production cross section times branching fraction for resonance decays to Z.W + gamma in the mass range from 1.0 to 6.8 TeV and for the first time into H + gamma in the mass range from 1.0 to 3.0 TeV.}, language = {en} } @article{OPUS4-22608, title = {Search for top squarks decaying to tau sleptons in \(pp\) collisions at root \(s\)=13 TeV with the ATLAS detector}, series = {Physical Review D}, volume = {98}, journal = {Physical Review D}, organization = {The ATLAS Collaboration}, doi = {10.1103/PhysRevD.98.032008}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-226080}, pages = {1-33}, year = {2018}, abstract = {A search for direct pair production of top squarks in final states with two tau leptons, b-jets, and missing transverse momentum is presented. The analysis is based on proton-proton collision data at root s = 13 TeV corresponding to an integrated luminosity of 36.1 fb(-1) recorded with the ATLAS detector at the Large Hadron Collider in 2015 and 2016. Two exclusive channels with either two hadronically decaying tau leptons or one hadronically and one leptonically decaying tau lepton are considered. No significant deviation from the Standard Model predictions is observed in the data. The analysis results are interpreted in terms of model-independent limits and used to derive exclusion limits on the masses of the top squark (t) over tilde (1) and the tau slepton (tau) over tilde (1) in a simplified model of supersymmetry with a nearly massless gravitino. In this model, masses up to m((t) over tilde (1)) = 1.16 TeV and m ((tau) over tilde (1)) = 1.00 TeV are excluded at 95\% confidence level.}, language = {en} } @article{OPUS4-22774, title = {Characterisation of the Hamamatsu photomultipliers for the KM3NeT Neutrino Telescope}, series = {Journal of Instrumentation}, volume = {13}, journal = {Journal of Instrumentation}, organization = {The KM3NeT collaboration}, doi = {10.1088/1748-0221/13/05/P05035}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-227744}, pages = {1-14}, year = {2018}, abstract = {The Hamamatsu R12199-023-inch photomultiplier tube is the photodetector chosen for the first phase of the KM3NeT neutrino telescope. About 7000 photomultipliers have been characterised for dark count rate, timing spread and spurious pulses. The quantum efficiency, the gain and the peak-to-valley ratio have also been measured for a sub-sample in order to determine parameter values needed as input to numerical simulations of the detector.}, language = {en} } @article{ChinaBurrowsWangetal.2018, author = {China, Swarup and Burrows, Susannah M. and Wang, Bingbing and Harder, Tristan H. and Weis, Johannes and Tanarhte, Meryem and Rizzo, Luciana V. and Brito, Joel and Cirino, Glauber G. and Ma, Po-Lun and Cliff, John and Artaxo, Paulo and Gilles, Mary K. and Laskin, Alexander}, title = {Fungal spores as a source of sodium salt particles in the Amazon basin}, series = {Nature Communications}, volume = {9}, journal = {Nature Communications}, doi = {10.1038/s41467-018-07066-4}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-222492}, year = {2018}, abstract = {In the Amazon basin, particles containing mixed sodium salts are routinely observed and are attributed to marine aerosols transported from the Atlantic Ocean. Using chemical imaging analysis, we show that, during the wet season, fungal spores emitted by the forest biosphere contribute at least 30\% (by number) to sodium salt particles in the central Amazon basin. Hydration experiments indicate that sodium content in fungal spores governs their growth factors. Modeling results suggest that fungal spores account for ~69\% (31-95\%) of the total sodium mass during the wet season and that their fractional contribution increases during nighttime. Contrary to common assumptions that sodium-containing aerosols originate primarily from marine sources, our results suggest that locally-emitted fungal spores contribute substantially to the number and mass of coarse particles containing sodium. Hence, their role in cloud formation and contribution to salt cycles and the terrestrial ecosystem in the Amazon basin warrant further consideration.}, language = {en} }