On the interface between perturbative and nonperturbative QCD

Journal Article · Wed Jun 01 00:00:00 EDT 2016 · Physics Letters B

DOI:https://doi.org/10.1016/j.physletb.2016.03.077· OSTI ID:1245477

Deur, Alexandre ; Brodsky, Stanley J.; de Téramond, Guy F.

The QCD running coupling α_s(Q²) sets the strength of the interactions of quarks and gluons as a function of the momentum transfer Q . The Q² dependence of the coupling is required to describe hadronic interactions at both large and short distances. In this article we adopt the light-front holographic approach to strongly-coupled QCD, a formalism which incorporates confinement, predicts the spectroscopy of hadrons composed of light quarks, and describes the low- Q² analytic behavior of the strong coupling α_s(Q²) . The high- Q² dependence of the coupling α_s(Q²) is specified by perturbative QCD and its renormalization group equation. The matching of the high and low Q² regimes of α_s(Q²) then determines the scale Q₀ which sets the interface between perturbative and nonperturbative hadron dynamics. The value of Q₀ can be used to set the factorization scale for DGLAP evolution of hadronic structure functions and the ERBL evolution of distribution amplitudes. We discuss the scheme-dependence of the value of Q₀ and the infrared fixed-point of the QCD coupling. Our analysis is carried out for the MS¯, g₁, MOM and V renormalization schemes. Our results show that the discrepancies on the value of α_s at large distance seen in the literature can be explained by different choices of renormalization schemes. Furthermore, we also provide the formulae to compute α_s(Q²) over the entire range of space-like momentum transfer for the different renormalization schemes discussed in this article.

• Research Organization: Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Nuclear Physics (NP)
• Grant/Contract Number: AC05-06OR23177; AC02-76SF00515; SLAC-PUB-16449
• OSTI ID: 1245477
• Alternate ID(s): OSTI ID: 1245546; OSTI ID: 1249326
• Report Number(s): JLAB-PHY-16-2198; SLAC-PUB-16449; DOE/OR/23177-3646; arXiv:1601.06568; S037026931630048X; PII: S037026931630048X
• Journal Information: Physics Letters B, Journal Name: Physics Letters B Vol. 757 Journal Issue: C; ISSN 0370-2693
• Publisher: Elsevier
• Country of Publication: Netherlands
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS