# 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)d is a sensitive measure of the strength of dynamical chiral symmetry breaking; and dTd measures the amount of axial-vector diquark correlation within the proton, vanishing if such correlations are absent.

- Authors:

- Publication Date:

- Research Org.:
- Argonne National Lab. (ANL), Argonne, IL (United States)

- Sponsoring Org.:
- USDOE Office of Science - Office of Nuclear Physics

- OSTI Identifier:
- 1391818

- DOE Contract Number:
- AC02-06CH11357

- Resource Type:
- Journal Article

- Resource Relation:
- Journal Name: Physical Review. D, Particles, Fields, Gravitation and Cosmology; Journal Volume: 91; Journal Issue: 7

- Country of Publication:
- United States

- Language:
- English

### Citation Formats

```
Pitschmann, Mario, Seng, Chien-Yeah, Roberts, Craig D., and Schmidt, Sebastian M.
```*Nucleon tensor charges and electric dipole moments*. United States: N. p., 2015.
Web. doi:10.1103/PhysRevD.91.074004.

```
Pitschmann, Mario, Seng, Chien-Yeah, Roberts, Craig D., & Schmidt, Sebastian M.
```*Nucleon tensor charges and electric dipole moments*. United States. doi:10.1103/PhysRevD.91.074004.

```
Pitschmann, Mario, Seng, Chien-Yeah, Roberts, Craig D., and Schmidt, Sebastian M. Wed .
"Nucleon tensor charges and electric dipole moments". United States.
doi:10.1103/PhysRevD.91.074004.
```

```
@article{osti_1391818,
```

title = {Nucleon tensor charges and electric dipole moments},

author = {Pitschmann, Mario and Seng, Chien-Yeah and Roberts, Craig D. and Schmidt, Sebastian M.},

abstractNote = {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)d is a sensitive measure of the strength of dynamical chiral symmetry breaking; and dTd measures the amount of axial-vector diquark correlation within the proton, vanishing if such correlations are absent.},

doi = {10.1103/PhysRevD.91.074004},

journal = {Physical Review. D, Particles, Fields, Gravitation and Cosmology},

number = 7,

volume = 91,

place = {United States},

year = {Wed Apr 01 00:00:00 EDT 2015},

month = {Wed Apr 01 00:00:00 EDT 2015}

}