Analytic result for the top-quark width at next-to-next-to-leading order in QCD

Abstract

We present the first full analytic results of next-to-next-to-leading order (NNLO) QCD corrections to the top-quark decay width $\Gamma (t\to Wb)$ by calculating the imaginary part of three-loop top-quark self-energy diagrams. The results are all expressed in terms of harmonic polylogarithms and valid in the whole region $0\le m_W^2\le m_t^2$. The expansions in the $m_W^2\to 0$ and $m_W^2\to m_t^2$ limits coincide with previous studies. Our results can also be taken as the exact prediction for the lepton invariant mass spectrum in semileptonic $b\to u$ decays. We also analytically compute the decay width including the off-shell $W$ boson effect up to NNLO in QCD for the first time. Combining these contributions with electroweak corrections and the finite $b$-quark mass effect, we determine the most precise top-quark width to be 1.331 GeV for $m_t=172.69$ GeV. The total theoretical uncertainties including those from renormalization scale choice, top-quark renormalization scheme, input parameters, and missing higher-order corrections are scrutinized and found to be less than $1\%$.

8 pages, 3 figures; v2: matching the published version in PRD

References in corpus (7)

• AMFlow: a Mathematica package for Feynman integrals computation via Auxiliary Mass Flow
• Measurement of the ratio B(t to Wb)/B(t to Wq) in pp collisions at sqrt(s) = 8 TeV
• Next-to-leading power endpoint factorization and resummation for off-diagonal "gluon" thrust
• Pole mass renormalon and its ramifications
• Extracting the Top-Quark Width from Non-Resonant Production
• QCD improved top-quark decay at next-to-next-to-leading order
• Top quark mass measurements at the $t\bar{t}$ threshold with CEPC

Cited by in corpus (8)

• Analytic three-loop QCD corrections to top-quark and semileptonic $b\to u$ decays
• Rare and exclusive few-body decays of the Higgs, Z, W bosons, and the top quark
• Using the $W$ as a Standard Candle to Reach the Top: Calibrating Energy Correlator Based Top Mass Measurements
• Review of top quark mass measurements in CMS
• Exclusive photon-fusion production of even-spin resonances and exotic QED atoms in high-energy hadron collisions
• Charming Darwin: the evolution of QCD parameters across different species
• A detailed study on the prospects for a $\mathrm{t}\overline{\mathrm{t}}$ threshold scan in ${\mathrm{e}}^{+}{\mathrm{e}}^{-}$ collisions
• Top-Quark Decay at Next-to-Next-to-Next-to-Leading Order in QCD