Transversity quark distributions in a covariant quark-diquark model

TL;DR

This paper calculates transversity quark distributions in the nucleon using a modified Nambu--Jona-Lasinio model with a quark-diquark approach, comparing results with experimental data and previous distributions.

Contribution

It introduces a covariant quark-diquark model with confinement simulation to compute transversity distributions, including scalar and axial-vector diquark channels.

Findings

Results agree with recent experimental transversity data.

Transversity distributions differ from spin-independent and helicity distributions.

Model successfully incorporates confinement effects.

Abstract

Transversity quark light-cone momentum distributions are calculated for the nucleon. We utilize a modified Nambu--Jona-Lasinio model in which confinement is simulated by eliminating unphysical thresholds for nucleon decay into quarks. The nucleon bound state is obtained by solving the relativistic Faddeev equation in the quark-diquark approximation, where both scalar and axial-vector diquark channels are included. Particular attention is paid to comparing our results with the recent experimental extraction of the transversity distributions by Anselmino et al. We also compare our transversity results with earlier spin-independent and helicity quark distributions calculated in the same approach.