1,721,084 research outputs found
Telling the spin of the “Higgs boson” at the LHC
No full textWe assume that the Higgs boson or a possible resonance—playing a role in strongly interacting models of electroweak symmetry breaking—has been discovered at the LHC, and we propose a search strategy to determine its spin based on two simple asymmetries in the ZZ, W+ W−, and t-t decay channels. We consider some benchmark values for its mass (above the ZZ threshold, in the interval from 182 GeV/c2 to 1 TeV/c2) and discuss the relative advantages of the different decay processes. A full analysis, including the background, is given. For a center-of-mass energy of 14 TeV, we find that the lowest integrated luminosity required to discriminate between the different spins is, depending on the process and the resonance mass, between 40 fb−1 and 250 fb−1
Corrigendum to “Measurements of Higgs boson production and couplings in diboson final states with the ATLAS detector at the LHC” [Phys. Lett. B 726 (1–3) (2013) 88]
No full textOne component of the statistical uncertainty on the results was erroneously assigned as a component of the systematic uncertainty. The value of the total uncertainty was not affected by this misassignment
Characterising the Higgs boson with ATLAS data from the LHC Run-2
No full textThe Higgs boson was discovered by the ATLAS and CMS Collaborations in 2012 using data from Run 1 of the Large Hadron Collider (2010−2012). In Run 2 (2015−2018), about 140 fb−1 of proton–proton collisions at a centre-of-mass energy of 13 TeV were collected by the ATLAS experiment. This review presents the most important Run 2 results obtained by the ATLAS Collaboration regarding the properties of the Higgs boson and its interactions with other particles. The performed studies significantly enhance the understanding of the Higgs boson, while hunting for deviations from the predictions of the Standard Model of particle physics
Climbing to the Top of the ATLAS 13 TeV data
No full textThe large amount of data recorded with the ATLAS detector at the Large Hadron Collider, corresponding to 140 fb−1 of pp collisions at a centre-of-mass energy of s = 13 TeV, has brought our knowledge of the top quark to a higher level. The measurement of the top–antitop quark pair-production cross-section has reached a precision of 1.8% and the cross-section was measured differentially up to several TeV in multiple observables including the top-quark transverse momentum and top-quark-pair invariant mass. Single-top-quark production was studied in all production modes. Rare production processes where the top quark is associated with a vector boson, and four-top-quark production, have become accessible and cross-section measurements for several of these processes have reached uncertainties of around 10% or smaller. Innovative measurements of the top-quark mass and properties have also emerged, including the observation of quantum entanglement in the top-quark sector and tests of lepton-flavour universality using top-quark decays. Searches for flavour-changing neutral currents in the top-quark sector have been significantly improved, reaching branching-ratio exclusion limits ranging from 10−3 to 10−5. Many of these analyses have been used to set limits on Wilson coefficients within the effective field theory framework
Erratum to “Comparison of inclusive and photon-tagged jet suppression in 5.02 TeV Pb+Pb collisions with ATLAS” [Phys. Lett. B 846 (2023) 138154]
No full textThe bottom panel of Fig. 7 did not include the systematic uncertainty band for gamma-tagged jets, and also did not include the two sets of dashed lines corresponding to the estimates of S_loss for inclusive and gamma-tagged jets when isospin and nPDF effects are included. The corrected version of Fig. 7 is shown below
Corrigendum to “Evidence of off-shell Higgs boson production from ZZ leptonic decay channels and constraints on its total width with the ATLAS detector” [Phys. Lett. B 846 (2023) 138223]
No full textA change in the method of estimating the Higgs boson width uncertainty was made towards the end of the internal review process. The plots, in particular Fig. 7a of the paper, were updated correctly to reflect this. However, the results given in the text were not updated, and as written are inconsistent with the results shown in the figure. Thus, the reported value of the Higgs boson width [Formula presented] was [Formula presented] MeV while it should have been [Formula presented] MeV. The reported observed (expected) value of the upper limit on [Formula presented] was 2.6 (2.7) when it should have been 2.5 (2.6). And the reported observed (expected) value of the upper limit on [Formula presented] was 10.5 (10.9) MeV while it should have been 10.2 (10.6) MeV
Erratum: Search for new phenomena in events with a photon and missing transverse momentum in pp collisions at root s = 8 TeV with the ATLAS detector [Phys. Rev. D 91, 012008 (2015)]
No full textOne correction is noted in our paper, which does not affect the results reported. The vertical axis range in the right panel of Fig.13 is corrected as it was not defined in exactly the same way as in the left panel, leading to misaligned axes
Exploration at the high-energy frontier: ATLAS Run 2 searches investigating the exotic jungle beyond the Standard Model
No full textThis report presents a comprehensive collection of searches for new physics performed by the ATLAS Collaboration during the Run 2 period of data taking at the Large Hadron Collider, from 2015 to 2018, corresponding to about 140 fb−1 of root s = 13 TeV proton–proton collision data. These searches cover a variety of beyond-the-standard model topics such as dark matter candidates, new vector bosons, hidden-sector particles, leptoquarks, or vector-like quarks, among others. Searches for supersymmetric particles or extended Higgs sectors are explicitly excluded as these are the subject of separate reports by the Collaboration. For each topic, the most relevant searches are described, focusing on their importance and sensitivity and, when appropriate, highlighting the experimental techniques employed. In addition to the description of each analysis, complementary searches are compared, and the overall sensitivity of the ATLAS experiment to each type of new physics is discussed. Summary plots and statistical combinations of multiple searches are included whenever possible
Erratum: Measurements of Wγ and Zγ production in pp collisions at root s = 7 TeV with the ATLAS detector at the LHC [Phys. Rev. D 87, 112003 (2013)]
No full textTwo corrections are noted for the paper [1]. These do not affect the results reported in the paper. They concern axis labels of two figures presented in the paper
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