Extraction of alpha_s from the energy evolution of jet fragmentation functions at low z

Understand

A novel method to extract the QCD coupling alpha_s from the energy evolution of the moments of the parton-to-hadron fragmentation functions at low fractional hadron momentum z, is presented.

• The evolution of the moments (multiplicity, peak, width, skewness) of the charged-hadron distribution in jets is computed at NMLLA+NLO* accuracy and compared to the experimental deep-inelastic e-p data.
• Values of the strong coupling constant at the Z pole are obtained, alpha_s(m_Z) = 0.119 +/- 0.010, in excellent numerical agreement with the current world average determined using other methods at the same level of accuracy.