Speaker
Description
Precision measurements provide a powerful probe of physics beyond the Standard Model, but their sensitivity is often limited by our ability to control hadronic effects. In this talk, I will focus on the hadronic contribution to the running of the electroweak gauge couplings, with particular emphasis on $\Delta\alpha_{\mathrm{had}}^{(5)}(M_Z^2)$.
I will present a recent high-precision lattice QCD determination of the hadronic vacuum polarization in the Euclidean region, reaching sub-percent precision and confirming tensions at space-like virtualities with data-driven estimates based on $e^+e^-$ cross sections. By combining the lattice calculation with the Euclidean split technique, we obtain a precise determination of the running of $\alpha$ up to the $Z$-pole and assess its implications for global electroweak fits. I will conclude with an outlook on further improvements and on the precision targets set by the FCC-ee program.