Constraining off-shell Higgs boson production and the Higgs boson total width using WW ...ll final states with the ATLAS detector <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si10.svg"> <mml:mrow> <mml:mi>W</mml:mi> <mml:mi>W</mml:mi> <mml:mo>→</mml:mo> <mml:mi>ℓ</mml:mi> <mml:mi>ν</mml:mi> <mml:mi>ℓ</mml:mi> <mml:mi>ν</mml:mi> </mml:mrow> </mml:math> final states with the ATLAS detector

A measurement of off-shell Higgs boson production is performed in the H * → W W channel. The measurement uses a proton–proton collision dataset with an integrated luminosity of 140 fb − 1 collected at a centre-of-mass energy of 13 TeV by the ATLAS detector at the Large Hadron Collider. Final states in which both W bosons decay leptonically are targeted, and events are categorised based on the flavour of the final-state leptons, the jet multiplicity, and the output of neural network-based classifiers. The data are found to be compatible with the Standard Model expectation. An observed (expected) upper bound on the 95% symmetric confidence level interval is set on the rate of off-shell Higgs boson production at a value of 3.4 (4.4) times the Standard Model prediction. These results are combined with the results from the measurement of on-shell Higgs boson production in the same final states to obtain an observed (expected) upper bound at 95 % confidence level on the Higgs boson total width of 13.1 (17.3) MeV

Search for cascade decays of charged sleptons and sneutrinos in final states with three leptons and missing transverse momentum in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>p</mml:mi><mml:mi>p</mml:mi></mml:math> collisions at <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msqrt><mml:mi>s</mml:mi></mml:msqrt><mml:mo>=</mml:mo><mml:mn>13</mml:mn><mml:mtext> </mml:mtext><mml:mtext> </mml:mtext><mml:mi>TeV</mml:mi></mml:math> with the ATLAS detector

A search for cascade decays of charged sleptons and sneutrinos using final states characterized by three leptons (electrons or muons) and missing transverse momentum is presented. The analysis is based on a dataset with 140  fb−1 of proton-proton () collisions at a center-of-mass energy of s=13  TeV recorded by the ATLAS detector at the Large Hadron Collider. This paper focuses on a supersymmetric scenario that is motivated by the muon anomalous magnetic moment observation, dark-mattter relic density abundance, and electroweak naturalness. A mass spectrum involving light Higgsinos and heavier sleptons with a bino at intermediate mass is targeted. No significant deviation from the Standard Model expectation is observed. This search enables us to place stringent constraints on this model, excluding at the 95% confidence level charged slepton and sneutrino masses up to 450 GeV when assuming a lightest neutralino mass of 100 GeV and mass-degenerate selectrons, smuons and sneutrinos.</jats:p

Observation of double parton scattering in same-sign W boson pair production in pp collisions at <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si42.svg"><mml:mrow><mml:msqrt><mml:mi>s</mml:mi></mml:msqrt><mml:mo linebreak="goodbreak">=</mml:mo><mml:mn>13</mml:mn></mml:mrow></mml:math> TeV with the ATLAS detector

This letter reports the measurement of double parton scattering in same-sign W boson pair production with the ATLAS detector. The data set used corresponds to an integrated luminosity of 140 fb − 1 of proton–proton collisions at a center-of-mass energy of 13 TeV, collected during Run 2 of the Large Hadron Collider. The study is performed in final states including two same-charge leptons, electron or muon, missing transverse momentum, and up to one jet. An excess of events is observed over the expected background contributions with a significance of 8.8 standard deviations. The measured fiducial cross section times leptonic branching fraction is 4.59 ± 0.64 fb. The measurement corresponds to a double parton scattering effective cross section of 10.6 ± 1.8 mb