Quark tensor charge and electric dipole moment within the Schwinger-Dyson formalism

TL;DR

This paper calculates the quark tensor charge using the Schwinger-Dyson formalism, finding significant suppression compared to the bare quark, and explores implications for the nucleon electric dipole moment.

Contribution

It provides a novel calculation of the dressed quark tensor charge within the Schwinger-Dyson approach, including effects of confinement and spin flip mechanisms.

Findings

Dressed tensor charge is significantly suppressed compared to bare quark.

Results qualitatively agree with lattice QCD and collinear factorization analyses.

Confinement effects are small in the tensor charge calculation.

Abstract

We calculate the tensor charge of the quark in the QCD-like theory in the Landau gauge using the Schwinger-Dyson formalism. It is found that the dressed tensor charge of the quark is significantly suppressed against the bare quark contribution, and the result agrees qualitatively with the analyses in the collinear factorization approach and lattice QCD. We also analyze the quark confinement effect with the phenomenological strong coupling given by Richardson, and find that this contribution is small. We show that the suppression of the quark tensor charge is due to the superposition of the spin flip of the quark arising from the successive emission of gluons which dress the tensor vertex. We also consider the relation between the quark and the nucleon electric dipole moments by combining with the simple constituent quark model.