Nucleon tensor charges and electric dipole moments

Abstract

A symmetry-preserving Dyson-Schwinger equation treatment of a vector-vector contact interaction is used to compute dressed-quark-core contributions to the nucleon $\sigma$-term and tensor charges. The latter enable one to directly determine the effect of dressed-quark electric dipole moments (EDMs) on neutron and proton EDMs. The presence of strong scalar and axial-vector diquark correlations within ground-state baryons is a prediction of this approach. These correlations are active participants in all scattering events and thereby modify the contribution of the singly-represented valence-quark relative to that of the doubly-represented quark. Regarding the proton $\sigma$-term and that part of the proton mass which owes to explicit chiral symmetry breaking, with a realistic $d$-$u$ mass splitting the singly-represented $d$-quark contributes 37% more than the doubly-represented $u$-quark; and in connection with the proton's tensor charges, ${\delta }_{T}u$, ${\delta }_{T}d$, the ratio ${\delta }_{T}d/{\delta }_{T}u$ is 18% larger than anticipated from simple quark models. Of particular note, the size of ${\delta }_{T}u$ is a sensitive measure of the strength of dynamical chiral symmetry breaking; and ${\delta }_{T}d$ measures the amount of axial-vector diquark correlation within the proton, vanishing if such correlations are absent.

20 pages, 6 figures, 4 tables. Corrected input Eqs.(B27), (B30). No material changes in computed results

References in corpus (19)

• Bridging a gap between continuum-QCD and ab initio predictions of hadron observables
• Soft-Gluon Resummation and the Valence Parton Distribution Function of the Pion
• Distribution Functions of the Nucleon and Pion in the Valence Region
• Abelian anomaly and neutral pion production
• pi- and rho-mesons, and their diquark partners, from a contact interaction
• Flavor decomposition of the elastic nucleon electromagnetic form factors
• Low Energy Precision Test of Supersymmetry
• Nucleon electromagnetic form factors from the covariant Faddeev equation
• Pion form factor from a contact interaction
• Masses of ground and excited-state hadrons
• Basic features of the pion valence-quark distribution function
• Pion and kaon valence-quark parton distribution functions
• Transversity quark distributions in a covariant quark-diquark model
• Parton distribution amplitudes of light vector mesons
• Transverse Spin Structure of the Nucleon through Target Single Spin Asymmetry in Semi-Inclusive Deep-Inelastic $(e,e^{\prime }{\pi }^{\pm })$ Reaction at Jefferson Lab
• Drell-Yan processes, transversity and light-cone wavefunctions
• Comparative analysis of the transversities and the longitudinally polarized distribution functions of the nucleon
• Dispersive estimate of the electromagnetic charge symmetry violation in the octet baryon masses
• Polarized structure functions of nucleons and nuclei

Cited by in corpus (4)

• Bridging a gap between continuum-QCD and ab initio predictions of hadron observables
• P- and T-Violating Lagrangians in Chiral Effective Field Theory and Nuclear Electric Dipole Moments
• QCD and Hadron Physics
• Quark scalar, axial and tensor charges in the Schwinger-Dyson formalism