Accurate nucleon electromagnetic form factors from dispersively improved chiral effective field theory

Journal Article · Sat Sep 01 00:00:00 EDT 2018 · Physics Letters B

DOI:https://doi.org/10.1016/j.physletb.2018.07.060· OSTI ID:1464272

Alarcón, J. M. ; Weiss, C.

We present a theoretical parametrization of the nucleon electromagnetic form factors (FFs) based on a combination of chiral effective field theory and dispersion analysis. The isovector spectral functions on the two-pion cut are computed using elastic unitarity, chiral pion-nucleon amplitudes, and timelike pion FF data. Higher-mass isovector and isoscalar t-channel states are described by effective poles, whose strength is fixed by sum rules (charges, radii). Excellent agreement with the spacelike proton and neutron FF data is achieved up to $$Q^2 \sim$$ 1 $GeV^2$. Here, our parametrization provides proper analyticity and theoretical uncertainty estimates and can be used for low-$Q^2$ FF studies and proton radius extraction.

• Research Organization: Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Nuclear Physics (NP)
• Grant/Contract Number: AC05-06OR23177; FPA2016-77313-P; FPA2016-75654-C2-2-P
• OSTI ID: 1464272
• Alternate ID(s): OSTI ID: 1469112
• Report Number(s): JLAB-THY-18-2675; DOE/OR/-23177-4402; arXiv:1803.09748; S0370269318306154; PII: S0370269318306154
• Journal Information: Physics Letters B, Journal Name: Physics Letters B Vol. 784 Journal Issue: C; ISSN 0370-2693
• Publisher: Elsevier
• Country of Publication: Netherlands
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
Nucleon form factors
Proton radius puzzle
Dispersion relations
Chiral effective field theory