# Peripheral transverse densities of the baryon octet from chiral effective field theory and dispersion analysis

## Abstract

The baryon electromagnetic form factors are expressed in terms of two-dimensional densities describing the distribution of charge and magnetization in transverse space at fixed light-front time. In this paper, we calculate the transverse densities of the spin-1/2 flavor-octet baryons at peripheral distances b=O(M$$-1\atop{π}$$) using methods of relativistic chiral effective field theory (χ EFT) and dispersion analysis. The densities are represented as dispersive integrals over the imaginary parts of the form factors in the timelike region (spectral functions). The isovector spectral functions on the two-pion cut t > 4 M$$2\atop{π}$$ are calculated using relativistic χEFT including octet and decuplet baryons. The χEFT calculations are extended into the ρ meson mass region using an N/D method that incorporates the pion electromagnetic form factor data. The isoscalar spectral functions are modeled by vector meson poles. We compute the peripheral charge and magnetization densities in the octet baryon states, estimate the uncertainties, and determine the quark flavor decomposition. Finally, the approach can be extended to baryon form factors of other operators and the moments of generalized parton distributions.

- Authors:

- Univ. of Bonn (Germany). Bethe Center for Theoretical Physics. Helmholtz Inst. for Radiation and Nuclear Physics; Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States). Theory Center
- Univ. of Valencia (Spain). Dept. of Theoretical Physics. Inst. for Corpuscular Physics (IFIC)
- Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States). Theory Center

- Publication Date:

- Research Org.:
- Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Univ. of Bonn (Germany); Univ. of Valencia (Spain)

- Sponsoring Org.:
- USDOE Office of Science (SC), Nuclear Physics (NP) (SC-26); German Research Foundation (DFG); Ministry of Economy, Industry and Competitiveness (MINECO) (Spain); European Commission (EC); Generalitat Valenciana

- OSTI Identifier:
- 1356984

- Alternate Identifier(s):
- OSTI ID: 1397938

- Report Number(s):
- JLAB-THY-17-2432

Journal ID: ISSN 0375-9474; PII: S0375947417301185; TRN: US1702506

- Grant/Contract Number:
- AC05-06OR23177; CRC 110; FPA2013-40483-P; FIS2014-51948-C2-2-P; SEV-2014-0398; PROMETEOII/2014/0068

- Resource Type:
- Journal Article: Accepted Manuscript

- Journal Name:
- Nuclear Physics. A

- Additional Journal Information:
- Journal Volume: 964; Journal ID: ISSN 0375-9474

- Publisher:
- Elsevier

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 73 NUCLEAR PHYSICS AND RADIATION PHYSICS; 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; Electromagnetic form factors; Chiral lagrangians; Dispersion relations; Hyperons; Charge distribution

### Citation Formats

```
Alarcón, J. M., Hiller Blin, A. N., Vicente Vacas, M. J., and Weiss, C.
```*Peripheral transverse densities of the baryon octet from chiral effective field theory and dispersion analysis*. United States: N. p., 2017.
Web. doi:10.1016/j.nuclphysa.2017.05.002.

```
Alarcón, J. M., Hiller Blin, A. N., Vicente Vacas, M. J., & Weiss, C.
```*Peripheral transverse densities of the baryon octet from chiral effective field theory and dispersion analysis*. United States. doi:10.1016/j.nuclphysa.2017.05.002.

```
Alarcón, J. M., Hiller Blin, A. N., Vicente Vacas, M. J., and Weiss, C. Mon .
"Peripheral transverse densities of the baryon octet from chiral effective field theory and dispersion analysis". United States.
doi:10.1016/j.nuclphysa.2017.05.002. https://www.osti.gov/servlets/purl/1356984.
```

```
@article{osti_1356984,
```

title = {Peripheral transverse densities of the baryon octet from chiral effective field theory and dispersion analysis},

author = {Alarcón, J. M. and Hiller Blin, A. N. and Vicente Vacas, M. J. and Weiss, C.},

abstractNote = {The baryon electromagnetic form factors are expressed in terms of two-dimensional densities describing the distribution of charge and magnetization in transverse space at fixed light-front time. In this paper, we calculate the transverse densities of the spin-1/2 flavor-octet baryons at peripheral distances b=O(M$-1\atop{π}$) using methods of relativistic chiral effective field theory (χ EFT) and dispersion analysis. The densities are represented as dispersive integrals over the imaginary parts of the form factors in the timelike region (spectral functions). The isovector spectral functions on the two-pion cut t > 4 M$2\atop{π}$ are calculated using relativistic χEFT including octet and decuplet baryons. The χEFT calculations are extended into the ρ meson mass region using an N/D method that incorporates the pion electromagnetic form factor data. The isoscalar spectral functions are modeled by vector meson poles. We compute the peripheral charge and magnetization densities in the octet baryon states, estimate the uncertainties, and determine the quark flavor decomposition. Finally, the approach can be extended to baryon form factors of other operators and the moments of generalized parton distributions.},

doi = {10.1016/j.nuclphysa.2017.05.002},

journal = {Nuclear Physics. A},

number = ,

volume = 964,

place = {United States},

year = {Mon May 08 00:00:00 EDT 2017},

month = {Mon May 08 00:00:00 EDT 2017}

}

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