The strong coupling from the IR to the UV extremes: Determination of $\alpha_s$ and prospects from EIC and JLab at 22 GeV

TL;DR

This paper demonstrates how the Bjorken sum rule enables the determination of the strong coupling constant $oldsymbol{_s}$ across a wide range of energies, including the infrared domain, and discusses future experimental prospects at EIC and JLab.

Contribution

It introduces a method to extract $oldsymbol{_s}$ over five orders of magnitude using the Bjorken sum rule and proposes future measurements at EIC and JLab to explore this further.

Findings

Determined $oldsymbol{_s}$ over five orders of magnitude in $Q$.

Proposed future measurements at EIC and JLab for $oldsymbol{_s}$.

Showed access to IR domain of QCD via sum rule analysis.

Abstract

We discuss how the Bjorken sum rule allows access to the QCD running coupling $\alpha_s$ at any scale, including in the deep infrared IR domain. The Bjorken sum data from Jefferson Lab, together with the world data on $\alpha_s$ reported by the Particle Data Group, allow us to determine the running of $\alpha_s(Q)$ over five orders of magnitude in four-momentum $Q$. We present two possible future measurements of the running of $\alpha_s(Q)$ using the Bjorken sum rule: the first at the EIC, covering the range $1.5 < Q < 8.7$ GeV, and the second at Jefferson Lab at 22 GeV, covering the range $1.0 < Q < 4.7$ GeV.