| 1. |
- Andrean, Stefio Y., 1991-, et al.
(författare)
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Comparison of inclusive and photon-tagged jet suppression in 5.02 TeV Pb+Pb collisions with ATLAS
- 2023
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Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 846
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Tidskriftsartikel (refereegranskat)abstract
- Parton energy loss in the quark-gluon plasma (QGP) is studied with a measurement of photon-tagged jet production in 1.7 nb-1 of Pb+Pb data and 260 pb-1 of pp data, both at root sNN = 5.02 TeV, with the ATLAS detector. The process pp -> gamma +jet+X and its analogue in Pb+Pb collisions is measured in events containing an isolated photon with transverse momentum (pT) above 50 GeV and reported as a function of jet pT. This selection results in a sample of jets with a steeply falling pT distribution that are mostly initiated by the showering of quarks. The pp and Pb+Pb measurements are used to report the nuclear modification factor, RAA, and the fractional energy loss, Sloss, for photon-tagged jets. In addition, the results are compared with the analogous ones for inclusive jets, which have a significantly smaller quark-initiated fraction. The RAA and Sloss values are found to be significantly different between those for photon-tagged jets and inclusive jets, demonstrating that energy loss in the QGP is sensitive to the colour-charge of the initiating parton. The results are also compared with a variety of theoretical models of colour-charge-dependent energy loss. (c) 2023 The Author(s). 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 SCOAP3.
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| 2. |
- Aad, G., et al.
(författare)
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Evidence for the Higgs Boson Decay to a Z Boson and a Photon at the LHC
- 2024
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Ingår i: Physical Review Letters. - : American Physical Society (APS). - 0031-9007 .- 1079-7114. ; 132:2
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Tidskriftsartikel (refereegranskat)abstract
- The first evidence for the Higgs boson decay to a Z boson and a photon is presented, with a statistical significance of 3.4 standard deviations. The result is derived from a combined analysis of the searches performed by the ATLAS and CMS Collaborations with proton-proton collision datasets collected at the CERN Large Hadron Collider (LHC) from 2015 to 2018. These correspond to integrated luminosities of around 140 fb−1 for each experiment, at a center-of-mass energy of 13 TeV. The measured signal yield is 2.2±0.7 times the standard model prediction, and agrees with the theoretical expectation within 1.9 standard deviations.
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| 3. |
- Aad, G., et al.
(författare)
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Measurement of the H→ γγ and H→ ZZ∗→ 4 ℓ cross-sections in pp collisions at √s=13.6 TeV with the ATLAS detector
- 2024
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Ingår i: European Physical Journal C. - : Institute for Ionics. - 1434-6044 .- 1434-6052. ; 84:1
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Tidskriftsartikel (refereegranskat)abstract
- The inclusive Higgs boson production cross-section is measured in the di-photon and the ZZ∗→ 4 ℓ decay channels using 31.4 and 29.0 fb - 1 of pp collision data respectively, collected with the ATLAS detector at a centre-of-mass energy of s=13.6 TeV . To reduce the model dependence, the measurement in each channel is restricted to a particle-level phase space that closely matches the channel’s detector-level kinematic selection, and it is corrected for detector effects. These measured fiducial cross-sections are σfid,γγ= 76-13+14 fb, and σfid,4ℓ= 2.80±0.74 fb, in agreement with the corresponding Standard Model predictions of 67.6 ± 3.7 fb and 3.67 ± 0.19 fb. Assuming Standard Model acceptances and branching fractions for the two channels, the fiducial measurements are extrapolated to the full phase space yielding total cross-sections of σ(pp→H)=67-11+12 pb and 46 ± 12 pb at 13.6 TeV from the di-photon and ZZ∗→ 4 ℓ measurements respectively. The two measurements are combined into a total cross-section measurement of σ(pp→ H) = 58.2 ± 8.7 pb, to be compared with the Standard Model prediction of σ(pp→ H) SM= 59.9 ± 2.6 pb.
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| 4. |
- Aad, G., et al.
(författare)
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Measurement of the production cross-section of J/ψ and ψ(2S) mesons in pp collisions at √s=13 TeV with the ATLAS detector
- 2024
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Ingår i: European Physical Journal C. - : Springer Nature. - 1434-6044 .- 1434-6052. ; 84:2
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Tidskriftsartikel (refereegranskat)abstract
- Measurements of the differential production cross-sections of prompt and non-prompt ?/? and ?(2S) mesons with transverse momenta between 8 and 360 GeV and rapidity in the range |?|<2 are reported. Furthermore, measurements of the non-prompt fractions of ?/? and ?(2S), and the prompt and non-prompt ?(2S)-to-?/? production ratios, are presented. The analysis is performed using 140 fb−1 of √?=13 TeV pp collision data recorded by the ATLAS detector at the LHC during the years 2015–2018.
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| 5. |
- Aad, G., et al.
(författare)
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Measurement of the t¯t¯ cross section and its ratio to the Z production cross section using pp collisions at √s=13.6 TeV with the ATLAS detector
- 2024
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Ingår i: Physics Letters B. - : Elsevier. - 0370-2693 .- 1873-2445. ; 848
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Tidskriftsartikel (refereegranskat)abstract
- The inclusive top-quark-pair production cross section ???̄ and its ratio to the ?-boson production cross section have been measured in proton–proton collisions at √? = 13.6 TeV, using 29 fb−1 of data collected in 2022 with the ATLAS experiment at the Large Hadron Collider. Using events with an opposite-charge electron-muon pair and ?-tagged jets, and assuming Standard Model decays, the top-quark-pair production cross section is measured to be ???̄ = 850± 3(stat.) ± 18(syst.) ± 20(lumi.) pb. The ratio of the ??̄ and the ?-boson production cross sections is also measured, where the ?-boson contribution is determined for inclusive ?+?− and ?+?− events in a fiducial phase space. The relative uncertainty on the ratio is reduced compared to the ??̄ cross section, thanks to the cancellation of several systematic uncertainties. The result for the ratio, ???̄∕? = 1.145 ± 0.003(stat.) ± 0.021(syst.)±0.002(lumi.) is consistent with the Standard Model prediction using the PDF4LHC21 PDF set.
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| 6. |
- Aad, G., et al.
(författare)
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Search for Majorana neutrinos in same-sign WW scattering events from pp collisions at √s=13 TeV
- 2023
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Ingår i: European Physical Journal C. - : Institute for Ionics. - 1434-6044 .- 1434-6052. ; 83:9
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Tidskriftsartikel (refereegranskat)abstract
- A search for Majorana neutrinos in same-sign WW scattering events is presented. The analysis uses √s=13 TeV proton–proton collision data with an integrated luminosity of 140 fb−1 recorded during 2015–2018 by the ATLAS detector at the Large Hadron Collider. The analysis targets final states including exactly two same-sign muons and at least two hadronic jets well separated in rapidity. The modelling of the main backgrounds, from Standard Model same-sign WW scattering and WZ production, is constrained with data in dedicated signal-depleted control regions. The distribution of the transverse momentum of the second-hardest muon is used to search for signals originating from a heavy Majorana neutrino with a mass between 50 GeV and 20 TeV. No significant excess is observed over the background expectation. The results are interpreted in a benchmark scenario of the Phenomenological Type-I Seesaw model. In addition, the sensitivity to the Weinberg operator is investigated. Upper limits at the 95% confidence level are placed on the squared muon-neutrino–heavy-neutrino mass-mixing matrix element |VμN|2 as a function of the heavy Majorana neutrino’s mass mN, and on the effective μμ Majorana neutrino mass |mμμ|.
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| 7. |
- Johansson, Anders, 1955-, et al.
(författare)
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Fermented rye bran as biocide replacement in paper production
- 2024
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Ingår i: 4th international conference strategies toward green deal implementation water, raw materials & energy. - Cracow : Publishing House, Mineral and Energy Economy Research Institute, Polish Academy of Sciences. - 9788367606271 ; , s. 78-78
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Konferensbidrag (refereegranskat)abstract
- Microbial contamination causes environmental and costly problems in paper production. Today, chemical-based biocides are used to control these problems. We have developed a biocide substitute that consists of fermented rest products from the cereal industry. Rye bran is a suitable nutrient for growth of a selected strain of Lactiplantibacillus plantarum. Previous studies have shown that fermented rye bran contains bioactive metabolites that powerfully limit virtually all bacterial growth. The cereals also contain fibres with potential to be a supplement in the raw material (pulp) of paper production. Our intention with this study was to investigate the potential of fermented rye bran as an antibacterial raw material in paper production. We will specifically determine the antibacterial effect of fermented rye bran on bacterial strains isolated from pulp and process water at a paper mill. In addition, to analyse the effect of the single metabolites discovered in the fermented rye bran. The results showed that fermented rye bran inhibited growth of the majority of the bacterial strains isolated from the paper mill. The pure metabolites showed also antibacterial properties, but less potent in comparison to the crude fermented rye bran product. The Lactobacillus strain used in the present study was resistant to all the tested metabolites. In conclusion, fermented rye bran shows properties indicating potential to be used as a bioactive raw material, limiting the need to add antimicrobial chemicals in paper production
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| 8. |
- Johansson, Anders, 1955-, et al.
(författare)
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Industrial rest materials as biocide replacement in paper production
- 2024
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Ingår i: Research workshop on bacillus in clinical and agricultural environments. - : German Multidisciplinary Publishing Center. ; , s. 15-15
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Konferensbidrag (refereegranskat)abstract
- Microbial contamination causes environmental and costly problems in paper production (gas formation in stored pulp, and biofilm/slime) and waste water systems (biofilm formation causing corrosion of the pipes). Today, chemical-based biocides are used to control these problems. We have developed a biocide substitute consisting of industrial rest products; rye bran or spruce bark. Rye bran is a suitable nutrient for growth of a selected strain of Lactiplantibacillus plantarum. Previous studies have shown that fermented rye bran, as well as spruce bark extracts, contains bioactive metabolites with the power to limit virtually all bacterial growth. These products also contain fibres with potential to be a supplement as raw material in the pulp.Our intention with this study was to investigate the potential of these rest materials as an antibacterial raw material in paper production. We will specifically determine the antibacterial effect on strains isolated from pulp, process water from the paper mill, and waste water pipes. In addition, likewise analyse the antimicrobial activity of single metabolites discovered in the crude extracts. The results so far, show that the products efficiently inhibit growth of the bacterial strains isolated from waste water and the paper mill. The pure metabolites showed also antibacterial properties, but were less potent as compared to the crude products. The Lactiplantiobacillus strain, used to ferment the rye bran in the present study, was resistant to all the tested products.In conclusion, fermented rye bran and spruce bark extracts show properties indicating a potential to be used as a bioactive raw material, limiting the need of adding synthetic biocides in paper production and waste water systems.
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| 9. |
- Moore, Edward R.B., et al.
(författare)
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Lachnoanaerobaculum
- 2021
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Ingår i: Bergey's Manual of Systematics of Archaea and Bacteria (BMSAB). - : John Wiley & Sons. - 9781118960608
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Bokkapitel (refereegranskat)abstract
- The genus Lachnoanaerobaculum comprises obligately anaerobic, Gram-stain-positive chemoorganotrophic, saccharolytic, and nonproteolytic bacilli. Cells are spore forming, rod shaped, and filamentous, 5 to greater than 20 μm in length, some cells with curving and swelling. All species of the genus grow with glucose as the sole carbon source. All species produce H2S, NH3, butyric acid, acetic acid, and lactic acid as metabolic end products. The predominant cellular fatty acids are C14:0, C16:0, and C18:1 ω7c DMA. The G + C contents of genomic DNA of the species are 35.0–37.8 mol%. Phylogenetic relationships of the species of Lachnoanaerobaculum, based on comparative 16S rRNA gene sequence analyses, indicate that they cluster within the phylum Firmicutes, within the family Lachnospiraceae, and exhibit a clear delineation to the other genera of the family, with a relatively close relationship to Johnsonella species. The first described strain of Lachnoanaerobaculum umeaense, the type species of the genus, was isolated from the jejunal mucosa of a child with coeliac disease. Strains of the species of Lachnoanaerobaculum are typically found in intestinal microbiota and oral microbiota of the human microbiome, isolated from the human gut, saliva, blood, amniotic fluid, and, predominantly, from the oral cavity.
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| 10. |
- Mullier, Geoffrey A., et al.
(författare)
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Search for the decay of the Higgs boson to a Z boson and a light pseudoscalar particle decaying to two photons
- 2024
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Ingår i: Physics Letters B. - : Elsevier B.V.. - 0370-2693 .- 1873-2445. ; 850
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Tidskriftsartikel (refereegranskat)abstract
- A search for the decay of the Higgs boson to a Z boson and a light, pseudoscalar particle, a, decaying respectively to two leptons and to two photons is reported. The search uses the full LHC Run 2 proton–proton collision data at √?=13 TeV, corresponding to 139 fb−1 collected by the ATLAS detector. This is one of the first searches for this specific decay mode of the Higgs boson, and it probes unexplored parameter space in models with axion-like particles (ALPs) and extended scalar sectors. The mass of the a particle is assumed to be in the range 0.1–33 GeV. The data are analysed in two categories: a merged category where the photons from the a decay are reconstructed in the ATLAS calorimeter as a single cluster, and a resolved category in which two separate photons are detected. The main background processes are from Standard Model Z boson production in association with photons or jets. The data are in agreement with the background predictions, and upper limits on the branching ratio of the Higgs boson decay to Za times the branching ratio ?→?? are derived at the 95% confidence level and they range from 0.08% to 2% depending on the mass of the a particle. The results are also interpreted in the context of ALP models.
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