Eur. Phys. J. A (2019) 55: 128
https://doi.org/10.1140/epja/i2019-12806-3

Regular Article - Theoretical Physics

Nucleon structure functions from the NJL-model chiral soliton

Institute for Theoretical Physics, Physics Department, Stellenbosch University, 7602, Matieland, South Africa

^* e-mail: weigel@sun.ac.za

Received: 27 March 2019
Accepted: 18 June 2019
Published online: 14 August 2019

Abstract

We present numerical simulations for unpolarized and polarized structure functions in a chiral soliton model. The soliton is constructed self-consistently from quark fields from which the structure functions are extracted. Central to the project is regularizing the Dirac sea (or vacuum) contribution to structure functions directly from the regularized action functional that defines the model. In turn, the structure functions are obtained from matrix elements of symmetry currents without assumptions on the nature of quark bilocal and bilinear operators. We discuss in detail how sum rules are realized at the level of the quark wave-functions in momentum space. The comparison with experimental data is convincing for the polarized structure functions but exhibits some discrepancies in the unpolarized case. The vacuum contribution to the polarized structure functions is particularly small.