Observation of photon-induced W+W− production in pp collisions at <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.svg"><mml:msqrt><mml:mrow><mml:mi>s</mml:mi></mml:mrow></mml:msqrt><mml:mo linebreak="goodbreak" linebreakstyle="after">=</mml:mo><mml:mn>13</mml:mn></mml:math> TeV using the ATLAS detector

This letter reports the observation of photon-induced production W-boson pairs, γγ→WW. The analysis uses 139 fb−1 LHC proton–proton collision data taken at s=13 TeV recorded by ATLAS experiment during years 2015–2018. measurement is performed selecting one electron and muon, corresponding to decay diboson system as WW→e±νμ∓ν final state. background-only hypothesis rejected with a significance well above 5 standard deviations consistent expectation from Monte Carlo simulation. A cross section for γγ→WW process 3.13±0.31(stat.)±0.28(syst.) fb measured in fiducial volume close acceptance detector, requiring an muon opposite signs large dilepton transverse momentum exactly zero additional charged particles. found be agreement Standard Model prediction.