| 1. |
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Övervakning av fåglar i skogsmark 2000
- 2000
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Reports (other academic/artistic)abstract
- Regional fågelövervakning i länets skogar. 22 rutter med 20 observationspunkter med 300 meters mellanrum. En utförlig redovisning av metodiken och de inventerade rutterna står att finna i Länsstyrelsen rapport: Övervakning av fåglar i skogsmark 1997Resultaten är datalagda i en Accessdatabas på Länsstyrelsen i Kronobergs län.
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| 2. |
- Aad, G, et al.
(author)
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Search for Higgs boson decays into two new low-mass spin-0 particles in the 4b channel with the ATLAS detector using pp collisions at s =13 TeV
- 2020
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In: Physical Review D. - : American Physical Society (APS). - 2470-0010 .- 2470-0029. ; 102:11
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Journal article (peer-reviewed)abstract
- This paper describes a search for beyond the Standard Model decays of the Higgs boson into a pair of new spin-0 particles subsequently decaying into b-quark pairs, H→aa→(bb¯)(bb¯), using proton-proton collision data collected by the ATLAS detector at the Large Hadron Collider at center-of-mass energy s=13 TeV. This search focuses on the range 15 GeV≤ma≤30 GeV, where the decay products are collimated; it is complementary to a previous search in the same final state targeting the range 20 GeV≤ma≤60 GeV, where the decay products are well separated. A novel strategy for the identification of the a→bb¯ decays is deployed to enhance the efficiency for topologies with small separation angles. The search is performed with 36 fb-1 of integrated luminosity collected in 2015 and 2016 and sets upper limits on the production cross section of H→aa→(bb¯)(bb¯), where the Higgs boson is produced in association with a Z boson. © 2020 CERN.
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| 3. |
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| 4. |
- Aad, G., et al.
(author)
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Study of High-Transverse-Momentum Higgs Boson Production in Association with a Vector Boson in the qqbb Final State with the ATLAS Detector
- 2024
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In: Physical Review Letters. - : American Physical Society (APS). - 0031-9007 .- 1079-7114. ; 132:13
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Journal article (peer-reviewed)abstract
- This Letter presents the first study of Higgs boson production in association with a vector boson (V ¼ W or Z) in the fully hadronic qqbb final state using data recorded by the ATLAS detector at the LHC in proton-proton collisions at √s = 13 TeV and corresponding to an integrated luminosity of 137 fb−1. The vector bosons and Higgs bosons are each reconstructed as large-radius jets and tagged using jet substructure techniques. Dedicated tagging algorithms exploiting b-tagging properties are used to identify jets consistent with Higgs bosons decaying into bb̄. Dominant backgrounds from multijet production are determined directly from the data, and a likelihood fit to the jet mass distribution of Higgs boson candidates is used to extract the number of signal events. The VH production cross section is measured inclusively and differentially in several ranges of Higgs boson transverse momentum: 250–450, 450–650, and greater than 650 GeV. The inclusive signal yield relative to the standard model expectation is observed to be μ = 1.4+1.0−0.9 and the corresponding cross section is 3.1 ± 1.3(stat)+1.8−1.4(syst) pb. © 2024 CERN, for the ATLAS Collaboration.
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| 5. |
- Aad, G, et al.
(author)
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Measurements of fiducial cross-sections for (Formula presented.) production with one or two additional b-jets in pp collisions at √s = 8 TeV using the ATLAS detector
- 2016
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In: European Physical Journal C. - : Springer-Verlag New York. - 1434-6044 .- 1434-6052. ; 76:1, s. 1-37
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Journal article (peer-reviewed)abstract
- Fiducial cross-sections for tt¯ production with one or two additional b-jets are reported, using an integrated luminosity of 20.3 fb-1 of proton–proton collisions at a centre-of-mass energy of 8 TeV at the Large Hadron Collider, collected with the ATLAS detector. The cross-section times branching ratio for tt¯ events with at least one additional b-jet is measured to be 950 ± 70 (stat.) -190 +240 (syst.) fb in the lepton-plus-jets channel and 50 ± 10 (stat.) -10 +15 (syst.) fb in the eμ channel. The cross-section times branching ratio for events with at least two additional b-jets is measured to be 19.3 ± 3.5 (stat.) ± 5.7 (syst.) fb in the dilepton channel (eμ, μμ, and ee) using a method based on tight selection criteria, and 13.5 ± 3.3 (stat.) ± 3.6 (syst.) fb using a looser selection that allows the background normalisation to be extracted from data. The latter method also measures a value of 1.30 ± 0.33 (stat.) ± 0.28 (syst.)% for the ratio of tt¯ production with two additional b-jets to tt¯ production with any two additional jets. All measurements are in good agreement with recent theory predictions.
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| 6. |
- Aad, G, et al.
(author)
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Search for charged-lepton-flavor violating Formula Presented interactions in top-quark production and decay in Formula Presented collisions at Formula Presented with the ATLAS detector at the LHC
- 2024
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In: Physical Review D. - : American Physical Society (APS). - 2470-0010 .- 2470-0029. ; 110:1
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Journal article (peer-reviewed)abstract
- A search for charged-lepton-flavor violating Formula Presented (Formula Presented, Formula Presented) interactions is presented, considering both top-quark production and decay. The data analyzed correspond to Formula Presented of proton-proton collisions at a center-of-mass energy of Formula Presented recorded with the ATLAS detector at the Large Hadron Collider. The analysis targets events containing two muons with the same electric charge, a hadronically decaying Formula Presented-lepton and at least one jet, with exactly one Formula Presented-tagged jet, produced by a Formula Presented interaction. Agreement with the Standard Model expectation within 1.6 standard deviations is observed, and limits are set at the 95% confidence level (CL) on the charged-lepton-flavor violation branching ratio of Formula Presented. An effective field theory interpretation is performed yielding 95% CL limits on Wilson coefficients, dependent on the flavor of the associated light quark and the Lorentz structure of the coupling. These range from Formula Presented for Formula Presented to Formula Presented for Formula Presented. An additional interpretation is performed for scalar leptoquark production inducing charged-lepton-flavor violation, with fixed intergenerational couplings. Upper limits on leptoquark coupling strengths are set at the 95% CL, ranging from Formula Presented to Formula Presented for leptoquark masses between 0.5 and 2.0 TeV. © 2024 CERN, for the ATLAS Collaboration.
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| 7. |
- Aad, G., et al.
(author)
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Searches for new phenomena in events with two leptons, jets, and missing transverse momentum in 139 fb−1 of √s=13 TeV pp collisions with the ATLAS detector
- 2023
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In: European Physical Journal C. - : Institute for Ionics. - 1434-6044 .- 1434-6052. ; 83:6
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Journal article (peer-reviewed)abstract
- Searches for new phenomena inspired by supersymmetry in final states containing an e+e− or μ+μ− pair, jets, and missing transverse momentum are presented. These searches make use of proton–proton collision data with an integrated luminosity of 139 fb−1, collected during 2015–2018 at a centre-of-mass energy √s=13 TeV by the ATLAS detector at the Large Hadron Collider. Two searches target the pair production of charginos and neutralinos. One uses the recursive-jigsaw reconstruction technique to follow up on excesses observed in 36.1 fb−1 of data, and the other uses conventional event variables. The third search targets pair production of coloured supersymmetric particles (squarks or gluinos) decaying through the next-to-lightest neutralino () via a slepton () or Z boson into ℓ+ℓ−, resulting in a kinematic endpoint or peak in the dilepton invariant mass spectrum. The data are found to be consistent with the Standard Model expectations. Results are interpreted using simplified models and exclude masses up to 900 GeV for electroweakinos, 1550 GeV for squarks, and 2250 GeV for gluinos.
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| 8. |
- Aad, G, et al.
(author)
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Measurement of the ZZ production cross section in pp collisions at √s = 13 TeV with the ATLAS detector
- 2016
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In: Physical Review Letters. - : American Physical Society. - 1079-7114 .- 0031-9007. ; 116:10
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Journal article (peer-reviewed)abstract
- The ZZ production cross section in proton-proton collisions at 13 TeV center-of-mass energy is measured using 3.2 fb-1 of data recorded with the ATLAS detector at the Large Hadron Collider. The considered Z boson candidates decay to an electron or muon pair of mass 66-116 GeV. The cross section is measured in a fiducial phase space reflecting the detector acceptance. It is also extrapolated to a total phase space for Z bosons in the same mass range and of all decay modes, giving 16.7-2.0+2.2(stat)+0.9-0.7(syst)+1.0-0.7(lumi) pb. The results agree with standard model predictions. © 2016 CERN. Published by the American Physical Society under the terms of the "http://creativecommons.org/licenses/by/3.0/" Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.
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| 9. |
- Aad, G, et al.
(author)
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Measurements of the Higgs boson inclusive and differential fiducial cross sections in the 4 ℓ decay channel at √s = 13 TeV
- 2020
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In: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 80:10
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Journal article (peer-reviewed)abstract
- Inclusive and differential fiducial cross sections of the Higgs boson are measured in the H→ ZZ∗→ 4 ℓ (ℓ= e, μ) decay channel. The results are based on proton−proton collision data produced at the Large Hadron Collider at a centre-of-mass energy of 13 TeV and recorded by the ATLAS detector from 2015 to 2018, equivalent to an integrated luminosity of 139 fb - 1. The inclusive fiducial cross section for the H→ ZZ∗→ 4 ℓ process is measured to be σfid= 3.28 ± 0.32 fb, in agreement with the Standard Model prediction of σfid , SM= 3.41 ± 0.18 fb. Differential fiducial cross sections are measured for a variety of observables which are sensitive to the production and decay of the Higgs boson. All measurements are in agreement with the Standard Model predictions. The results are used to constrain anomalous Higgs boson interactions with Standard Model particles. © 2020, The Author(s).
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| 10. |
- Aad, G., et al.
(author)
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Search for heavy Higgs bosons with flavour-violating couplings in multi-lepton plus b-jets final states in pp collisions at 13 TeV with the ATLAS detector
- 2023
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In: Journal of High Energy Physics (JHEP). - : Springer Nature. - 1126-6708 .- 1029-8479. ; 2023:12
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Journal article (peer-reviewed)abstract
- A search for new heavy scalars with flavour-violating decays in final states with multiple leptons and b-tagged jets is presented. The results are interpreted in terms of a general two-Higgs-doublet model involving an additional scalar with couplings to the top-quark and the three up-type quarks (). The targeted signals lead to final states with either a same-sign top-quark pair, three top-quarks, or four top-quarks. The search is based on a data sample of proton-proton collisions at √s = 13 TeV recorded with the ATLAS detector during Run 2 of the Large Hadron Collider, corresponding to an integrated luminosity of 139 fb−1. Events are categorised depending on the multiplicity of light charged leptons (electrons or muons), total lepton charge, and a deep-neural-network output to enhance the purity of each of the signals. Masses of an additional scalar boson mH between 200 − 630 GeV with couplings , , and are excluded at 95% confidence level. Additional interpretations are provided in models of R-parity violating supersymmetry, motivated by the recent flavour and (g − 2)μ anomalies.
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