Measurement of vector boson production cross sections and their ratios using $pp$ collisions at $\sqrt{s}=13.6$ TeV with the ATLAS detector

Fiducial and total $W^\pm$ and $Z$ boson cross sections, their ratios and the ratio of top-antitop-quark pair and $W$-boson fiducial cross sections are measured in proton-proton collisions at a centre-of-mass energy of $\sqrt{s}=13.6$ TeV, corresponding to an integrated luminosity of 29 fb$^{-1}$ of data collected in 2022 by the ATLAS experiment at the Large Hadron Collider. The measured fiducial cross-section values for $W^+\to \ell^+\nu$, $W^-\to \ell^-\bar{\nu}$, and $Z\to \ell^+\ell^-$ ($\ell=e$ or $\mu$) boson productions are $4250\pm 150$ pb, $3310\pm 120$ pb, and $744\pm 20$ pb, respectively, where the uncertainty is the total uncertainty, including that arising from the luminosity of about 2.2%. The measurements are in agreement with Standard-Model predictions calculated at next-to-next-to-leading-order in $\alpha_s$, next-to-next-to-leading logarithmic accuracy and next-to-leading-order electroweak accuracy.