The Standard Model (SM) of particle physics is the best model available to describe the fundamental constituents of matter and their interaction.
After the discovery of the Higgs boson, a key ingredient of the SM, much has been learned about Higgs properties and the SM.
The mass of the Higgs boson is now measured with a precision better than 0.2%. For a Higgs boson of mass 125 GeV, the SM expectation for the width is 4 MeV. A direct measurement at the resonance peak is therefore limited by the experimental resolution of the LHC detectors.
The Higgs boson width is a fundamental measurement providing global information on the Higgs decays, including decays to particles not visible in the LHC detectors.
A novel technique based on the off-shell production of the Higgs boson is currently used at the LHC to make this measurement possible.
A review of the latest measurements performed by the ATLAS collaboration with Run-2 data collected in 2015 and in 2016 is presented. Prospects at HL-LHC and at future e+e- machines are also presented.
