Speaker
David d'Enterria
(CERN)
Description
The hadronic branching ratio of the W boson $BR_{had}$, computed today at next-to-next-to-leading order (NNLO) accuracy, can be used to determine the QCD coupling $\alpha_s$ using the experimental data to be collected in $e^+e^- \to W^+W^-$ processes at the FCC-ee. By exploiting the huge data sample of $5 \times 10^8$ W bosons (a thousand times more than the $5 \times 10^5$ W's collected at LEP), the statistical uncertainty on $BR_{had}$ can be reduced to around 0.005\%. By combining the measurement of $BR_{had}$ and $(1- BR_{lep})$, alpha_s can be extracted with a state-of-the-art experimental uncertainty of order 0.2\%. The associated parametric and theoretical uncertainties of such an alpha_s determination will be also discussed.
Primary author
David d'Enterria
(CERN)
