Abstract
A measurement of inclusive and differential fiducial cross-sections for the
production of the Higgs boson decaying into two photons is performed using
$139~\text{fb}^{-1}$ of proton--proton collision data recorded at $\sqrt{s} =
13$ TeV by the ATLAS experiment at the Large Hadron Collider. The inclusive
cross-section times branching ratio, in a fiducial region closely matching the
experimental selection, is measured to be $67\pm 6$ fb, which is in agreement
with the state-of-the-art Standard Model prediction of $64\pm 4$ fb.
Extrapolating this result to the full phase space and correcting for the
branching ratio, the total cross-section for Higgs boson production is
estimated to be $58\pm 6$ pb. In addition, the cross-sections in four fiducial
regions sensitive to various Higgs boson production modes and differential
cross-sections as a function of either one or two of several observables are
measured. All the measurements are found to be in agreement with the Standard
Model predictions. The measured transverse momentum distribution of the Higgs
boson is used as an indirect probe of the Yukawa coupling of the Higgs boson to
the bottom and charm quarks. In addition, five differential cross-section
measurements are used to constrain anomalous Higgs boson couplings to vector
bosons in the Standard Model effective field theory framework.