Structure function evolution at next-to-leading order and beyond

TL;DR

This paper investigates the evolution of deep-inelastic structure functions at NLO and beyond, providing fits to experimental data and discussing the importance of higher-order corrections for reducing theoretical uncertainties.

Contribution

It presents NLO fits to structure function data and discusses the necessity of NNLO calculations to improve theoretical precision.

Findings

NLO fits yield alpha_s(M_Z) = 0.114 ± 0.002 (experimental) ± 0.006 (theoretical)

Theoretical error is dominated by renormalization-scale dependence

Available calculations are sufficient for NNLO in the non-singlet sector at x > 10^-2

Abstract

Results are presented of two studies addressing the scaling violations of deep-inelastic structure functions. Factorization-scheme independent fits to all ep and mu p data on F_2 are performed at next-to-leading order (NLO), yielding alpha_s(M_Z) = 0.114 +- 0.002_exp (+0.006-0.004)_th . In order to reduce the theoretical error dominated by the renormalization-scale dependence, the next-higher order (NNLO) needs to be included. For the flavour non-singlet sector, it is shown that available calculations provide sufficient information for this purpose at x > 10^-2.