Power corrections in the longitudinal and transverse structure functions of proton and deuteron

TL;DR

This paper investigates power corrections to the structure functions of proton and deuteron, analyzing data between 1 and 20 GeV/c² to understand higher-twist effects and target-mass contributions.

Contribution

It provides a detailed analysis of higher-twist effects using Natchmann moments and renormalon-inspired models, distinguishing between longitudinal and transverse channels.

Findings

Transverse channel shows multiparton correlations affecting 1/Q² and 1/Q⁴ terms.

Longitudinal channel consistent with infrared renormalon model.

Deuteron twist-2 contribution suggests an enhanced d-quark distribution at large x.

Abstract

Power corrections to the Q**2 behaviour of the low-order moments of both the longitudinal and transverse structure functions of proton and deuteron have been investigated using available phenomenological fits of existing data in the Q**2 range between 1 and 20 (GeV/c)**2. The Natchmann definition of the moments has been adopted for disentangling properly target-mass and dynamical higher-twist effects in the data. The leading twist has been treated at next-to-leading order in the strong coupling constant and the effects of higher orders of the perturbative series have been estimated using a renormalon-inspired model. The contributions of (target-dependent) multiparton correlations to both 1/Q**2 and 1/Q**4 power terms have been determined in the transverse channel, while the longitudinal one appears to be consistent with a pure infrared renormalon picture in the whole Q**2-range between 1 and 20 (GeV/c)**2. Finally, the extracted twist-2 contribution in the deuteron turns out to be compatible with the hypothesis of an enhanced d-quark parton distribution at large x.