QCD coupling below 1 GeV from the quarkonium spectrum

M. Baldicchi, A. V. Nesterenko, G. M. Prosperi, and C. Simolo
Phys. Rev. D 77, 034013 – Published 19 February 2008

Abstract

In this paper we extend the work synthetically presented by M. Baldicchi, A. V. Nesterenko, G. M. Prosperi, D. V. Shirkov, and C. Simolo [Phys. Rev. Lett. 99, 242001 (2007)] and give theoretical details and a complete set of numerical results. We exploit calculations within a Bethe-Salpeter (BS) formalism adjusted for QCD, in order to extract an experimental strong coupling αsexp(Q2) below 1 GeV by comparison with the meson spectrum. The BS potential follows from a proper ansatz on the Wilson loop to encode confinement and is the sum of a one-gluon-exchange term and a confinement term. Besides, the common perturbative strong running coupling is replaced by the ghost-free expression αE(Q2) according to the prescription of analytic perturbation theory (APT). The agreement of αsexp(Q2) with the APT coupling αE(Q2) turns out to be reasonably good from 1 GeV down to 200 MeV, thus confirming quantitatively the validity of the APT prescription in this range. Below this scale, the experimental points could give a hint on the vanishing of αs(Q2) as Q2 approaches zero. This infrared behavior would be consistent with some lattice results as well as with the massive modification of the APT approach. As a main result, we claim that the combined BS-APT theoretical scheme provides quite satisfactory correlated understanding of very high and rather low energy phenomena from a few hundred MeV to a few hundred GeV.

  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
  • Received 16 May 2007

DOI:https://doi.org/10.1103/PhysRevD.77.034013

©2008 American Physical Society

Authors & Affiliations

M. Baldicchi1, A. V. Nesterenko2, G. M. Prosperi1, and C. Simolo1

  • 1Dipartimento di Fisica, Università di Milano and INFN, Sezione di Milano, Via Celoria 16, I20133 Milano, Italy
  • 2Bogoliubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, Dubna, 141980, Russia

Article Text (Subscription Required)

Click to Expand

References (Subscription Required)

Click to Expand
Issue

Vol. 77, Iss. 3 — 1 February 2008

Reuse & Permissions
Access Options

Authorization Required


×
×

Images

×

Sign up to receive regular email alerts from Physical Review D

Log In

Cancel
×

Search


Article Lookup

Paste a citation or DOI

Enter a citation
×