Probability-based estimates of the uncalculated N5LO QCD contribution to the hadronic W-boson decay width
Year: 2026
Type: article
Abstract: The perturbative QCD corrections to the hadronic decay width of the W boson are currently known up to next-to-next-to-next-to-next-to-leading order ( $$\mathrm {N^4LO}$$ N 4 LO ), whereas the exact $$\mathrm {N^5LO}$$ N 5 LO correction remains unavailable owing to its formidable computational complexity. In this work, we estimate the $$\mathrm {N^5LO}$$ N 5 LO contributions by adopting Bayesian analysis (BA). Before performing the estimation, the principle of maximum conformality (PMC) is employed to improve the precision of the initial scale-dependent perturbative series. Through recursive application of the renormalization group equation, non-conformal terms are absorbed into the strong running coupling, yielding a scheme-independent, scale-invariant perturbative series with improved convergence. The PMC procedure determines an effective coupling $$\alpha _s(Q_*)$$ α s ( Q ∗ ) , with the PMC scale fixed as $$Q_*\!=\!100.102~\textrm{GeV}$$ Q ∗ = 100.102 GeV at next-to-next-to-leading logarithmic accuracy. Based on the improved and more precise series, the $$95.5\%$$ 95.5 % BA credible interval yields an uncertainty of $$\Delta \delta _\textrm{QCD}|_{\textrm{PMC, BA}}^{\mathrm {N^5LO}} = \pm 1.0\times 10^{-5}$$ Δ δ QCD | PMC, BA N 5 LO = ± 1.0 × 10 - 5 . The resulting hadronic branching ratio is $$\mathcal {B}(W\rightarrow \text {hadrons})|_\textrm{PMC} = (65.84\pm 1.54)\%$$ B ( W → hadrons ) | PMC = ( 65.84 ± 1.54 ) % , which is consistent with experimental data within reasonable errors.
Source: The European Physical Journal C
Authors: Shu-Heng Yang, Jiang Yan, Xing-Gang Wu, Zhi-Fei Wu
Institutions: Chongqing University, Chinese Academy of Sciences
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: diamond
Awards: G7223305753, G7902198378, G9001175298
OpenAlex ID: W7204884733