Abstract
We propose a new strategy for the determination of the QCD coupling. It relies on a coupling computed in QCD with Nf≥3 degenerate heavy quarks at a low energy scale μdec, together with a non-perturbative determination of the ratio Λ/μdec in the pure gauge theory. We explore this idea using a finite volume renormalization scheme for the case of Nf=3 QCD, demonstrating that a precise value of the strong coupling αs can be obtained. The idea is quite general and can be applied to solve other renormalization problems, using finite or infinite volume intermediate renormalization schemes.
Highlights
The best estimates of αs(mZ ) reach a precision below 1%, with lattice QCD providing the most precise determinations [1,2,3,4,5,6,7,8]
The main challenge in a solid extraction of αs by using lattice QCD is the estimate of perturbative truncation uncertainties, other power corrections, and finite lattice spacing errors which are present in all extractions
In this paper we propose a new strategy for the computation of the strong coupling
Summary
The best estimates of αs(mZ ) reach a precision below 1%, with lattice QCD providing the most precise determinations [1,2,3,4,5,6,7,8]. It has recently been applied to three flavor QCD, yielding αs(mZ ) with very high precision by means of a non-perturbative running from scales of 0.2 GeV to 70 GeV [8,12,9] and perturbation theory above. In this paper we propose a new strategy for the computation of the strong coupling It is based on QCD with Nf ≥ 3 quarks. /μdec relates the same coupling and the renormalization scale μ = μdec in the zero-flavor theory and the function P gives the ratio (0) / (Nf). Simulating heavy quarks on the lattice is a challenging multiscale problem, but defining the intermediate scheme, s, in a finite volume allows us to reach large quark masses M ≈ Mbottom
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