Determination of the effective strong coupling constant alpha_{s,g_1}(Q^2) from CLAS spin structure function data

TL;DR

This paper presents a new measurement of the effective strong coupling constant lpha_{s,g_1}(Q^2) using CLAS spin structure function data, confirming its Q^2-independence at low Q^2 and providing a useful parameterization for QCD sum rule applications.

Contribution

It offers a novel extraction of lpha_{s,g_1}(Q^2) extending previous measurements and verifying its low Q^2 behavior crucial for AdS/CFT applications in QCD.

Findings

lpha_{s,g_1}(Q^2) is Q^2-independent at low Q^2.

The new lpha_{s,g_1}(Q^2) agrees with previous determinations.

A parameterization of lpha_{s,g_1}(Q^2) is provided for theoretical applications.

Abstract

We present a new extraction of the effective strong coupling constant \alpha_{s,g_1}(Q^2). The result agrees with a previous determination and extends the measurement of the low and high Q^2 behavior of \alpha_{s,g_1}(Q^2) that was previously deduced from sum rules. In particular, it experimentally verifies the lack of Q^2-dependence of \alpha_{s,g_1}(Q^2) in the low Q^2 limit. This fact is necessary for application of the AdS/CFT correspondence to QCD calculations. We provide a parameterization of \alpha_{s,g_1}(Q^2) thatcan equivalently be used to parameterize the Q^2-dependence of the generalized Gerasimov-Drell-Hearn and Bjorken sums.