Uncertainties on the determination of the strong coupling alpha_s from the energy evolution of jet fragmentation functions at low z

TL;DR

This paper determines the strong coupling constant alpha_s at the Z boson mass using jet fragmentation data, achieving a precise measurement with detailed uncertainty analysis at NLO*+NMLLA accuracy.

Contribution

It introduces a method to extract alpha_s from the energy evolution of fragmentation function moments at low z, incorporating NLO*+NMLLA theoretical predictions and analyzing existing experimental data.

Findings

alpha_s(m_Z^2) = 0.1195 +/- 0.0021 (exp.) +0.0015/-0.0 (scale)

Uncertainties in alpha_s are thoroughly discussed

Method combines jet data with advanced QCD predictions

Abstract

The QCD coupling alpha_s is determined at NLO*+NMLLA accuracy from the comparison of experimental jet data to theoretical predictions of the energy-evolution of the parton-to-hadron fragmentation function moments (multiplicity, peak, width, skewness) at low fractional hadron momentum z. From the existing e+e- and e-p jet data, we obtain alpha_s(m_Z^2) = 0.1195 +/- 0.0021 (exp.) {+0.0015}_{-0.0} (scale) at the Z mass. The uncertainties of the extracted alpha_s value are discussed.