Higgs total width at the ATLAS experiment

<!--HTML--><div>With a value of about 4 MeV, the total width of the &nbsp;Higgs boson in the Standard Model is not accessible via direct measurements at the LHC as the experimental resolution is around 1 GeV.</div><div>Instead, a comparison of off-shell and on-shell Higgs boson production can reveal the value of the width under mild assumptions on the Higgs boson couplings.<br>This seminar presents a new measurement of the &nbsp;Higgs boson off-shell production and its natural width based on &nbsp;the full Run 2 pp dataset &nbsp;collected at 13 TeV.<br>The measurement exploits the gluon-fusion and vector-boson fusion production modes, and the decays channels into ZZ→4l and ZZ→2l2v.&nbsp;<br>The background-only hypothesis is rejected with an observed (expected) significance of 3.2 (2.4) 𝜎, which marks the experimental evidence of off-shell Higgs production.</div><div>&nbsp;</div>