QCD coupling which respects lattice restrictions at low energies

TL;DR

This paper introduces a phenomenological QCD coupling model that respects lattice constraints at low energies, matching perturbative behavior at high energies and experimental data at intermediate scales, with applications to various low-energy QCD observables.

Contribution

It proposes a new QCD coupling parametrization based on dispersion relations that incorporates lattice results and matches experimental data across energy scales.

Findings

The model reproduces perturbative QCD at high energies.

It aligns with lattice results in the IR regime.

It successfully describes experimental data for tau decay and sum rules.

Abstract

We consider a phenomenologycal parametrization of the QCD running coupling which arises from the dispersion relation respecting the holomorphic properties of the physical QCD observables in the complex momentum plane. The parameters are fixed by the following requirements: 1) at enough high energies, it reproduces the underlying perturbative coupling, 2) at intermediate energy momenta, it reproduces the experimental semihadronic tau decay ratio, and 3) in the deep IR regime, it satisfies the qualitative properties coming from recent lattice results. Finally, we apply this new coupling to low-energy available experimental data. In particular, to Borel sum rules for {\tau}-decay, extracting the values of the dimension 4 and 6 condensates, to the V-channel Adler function, and to polarized Bjorken Sum Rule.