1998/03/31 by Jens Erler · 104 citations
Physics and Astronomy · #Annihilation #Charm (quantum number) #Coupling (piping) #Electroweak interaction #Hadron #High-Energy Particle Collisions Research #Mathematical physics #Particle physics #Particle physics theoretical and experimental studies #Physics #Quantum Chromodynamics and Particle Interactions #Quantum chromodynamics #Renormalization #hep-ph
paper · pdf · doi:10.1103/physrevd.59.054008
published in Physical review. D. Particles, fields, gravitation, and cosmology/Physical review. D. Particles and fields 59(5) (American Physical Society) · 7 pages, 1 figure; added: discussion of non-perturbative effects; discussion of charm and bottom quark mass averages; references
arxiv created 1998/11/09 · openalex publication_date 1999/02/01 · arxiv updated 2010/04/06 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
I calculate the QED coupling \stackrel^\ensuremathα directly in the MS scheme using an unsubtracted dispersion relation for the three light quarks and perturbative QCD for charm and bottom quarks. Compact analytical expressions are presented, making this approach particularly suitable for electroweak fits. After \stackrel^\ensuremathα^\ensuremath-1(m_\ensuremathτ)=133.513\ifmmode±\else\textpm\fi0.026 is obtained in the first step, I perform a four-loop renormalization group evolution with three-loop matching conditions to arrive at \stackrel^\ensuremathα^\ensuremath-1(MZ)=127.934\ifmmode±\else\textpm\fi0.027 for \stackrel^\ensuremathαs(MZ)=0.120. The corresponding hadronic contribution to the on-shell coupling is \ensuremathΔ\ensuremathαhad(5)(MZ)=0.02779\ifmmode±\else\textpm\fi0.00020. The error is mainly from mc, and from experimental uncertainties in e+e^\ensuremath- annihilation into unflavored and strange hadrons and \ensuremathτ decay data.