524 research outputs found

    Search for new phenomena in multi-body invariant masses in events with at least one isolated lepton and two jets using √s = 13 TeV proton–proton collision data collected by the ATLAS detector

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    A search for resonances in events with at least one isolated lepton (e or μ) and two jets is performed using 139 fb −1 of s = 13 TeV proton–proton collision data recorded by the ATLAS detector at the LHC. Deviations from a smoothly falling background hypothesis are tested in three- and four-body invariant mass distributions constructed from leptons and jets, including jets identified as originating from bottom quarks. Model-independent limits on generic resonances characterised by cascade decays of particles leading to multiple jets and leptons in the final state are presented. The limits are calculated using Gaussian shapes with different widths for the invariant masses. The multi-body invariant masses are also used to set 95% confidence level upper limits on the cross-section times branching ratios for the production and subsequent decay of resonances predicted by several new physics scenarios. [Figure not available: see fulltext.]

    Evidence for the production of three massive vector bosons with the ATLAS detector

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    A search for the production of three massive vector bosons in proton–proton collisions is performed using data at √s = 13 TeV recorded with the ATLAS detector at the Large Hadron Collider in the years 2015–2017, corresponding to an integrated luminosity of 79.8 fb−1. Events with two same-sign leptons (electrons or muons) and at least two reconstructed jets are selected to search for WWW → ννqq. Events with three leptons without any same-flavour opposite-sign lepton pairs are used to search for WWW → ννν, while events with three leptons and at least one same-flavour opposite-sign lepton pair and one or more reconstructed jets are used to search for WWZ → νqq. Finally, events with four leptons are analysed to search for WWZ → νν and WZZ → qq. Evidence for the joint production of three massive vector bosons is observed with a significance of 4.1 standard deviations, where the expectation is 3.1 standard deviations
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