Observation of gauge boson joint-polarisation states in W±Z production from 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 with the ATLAS detector

Measurements of joint-polarisation states W and Z gauge bosons in W±Z production are presented. The data set used corresponds to an integrated luminosity 139 fb−1 proton–proton collisions at a centre-of-mass energy 13 TeV recorded by the ATLAS detector CERN Large Hadron Collider. candidate events reconstructed using leptonic decay modes into electrons muons. simultaneous pair-production longitudinally polarised vector is measured for first time with significance 7.1 standard deviations. joint helicity fractions over fiducial region f00=0.067±0.010, f0T=0.110±0.029, fT0=0.179±0.023 fTT=0.644±0.032, agreement next-to-leading-order Standard Model predictions. Individual also found be consistent within expected amounts correlation. Both individual separately W+Z W−Z events. Inclusive differential cross sections several kinematic observables sensitive polarisation