Abstract
Abstract:
A measurement of off-shell Higgs boson production in the Z Z → 4t and Z Z → 2t2ν decay channels,
where t stands for either an electron or a muon, is performed using data
from proton–proton collisions at a centre-of-mass energy of √s = 13 TeV. The data were
collected by the ATLAS experiment in 2015 and 2016 at the Large Hadron Collider, and they
correspond to an integrated luminosity of 36.1 fb−1. An observed (expected) upper limit on the
off-shell Higgs signal strength, defined as the event yield normalised to the Standard Model
prediction, of 3.8 (3.4) is obtained at 95% confidence level (CL). Assuming the ratio of the Higgs
boson couplings to the Standard Model predictions is independent of the momentum transfer of the
Higgs production mechanism considered in the analysis, a combination with the on-shell
signal-strength measurements yields an observed (expected) 95% CL upper limit
on the Higgs boson total width of 14.4 (15.2) MeV.