Abstract
We present the first measurements of the electric and magnetic form factors of the neutron in the timelike (positive ) region as function of four-momentum transfer. We explored the differential cross sections of the reaction with data collected with the BESIII detector at the BEPCII accelerator, corresponding to an integrated luminosity of in total at twelve center-of-mass energies between . A relative uncertainty of 18% and 12% for the electric and magnetic form factors, respectively, is achieved at . Our results are comparable in accuracy to those from electron scattering in the comparable spacelike region of four-momentum transfer. The electromagnetic form factor ratio is within the uncertainties close to unity. We compare our result on and to recent model predictions, and the measurements in the spacelike region to test the analyticity of electromagnetic form factors.
- Received 15 December 2022
- Revised 27 February 2023
- Accepted 23 March 2023
- Corrected 27 June 2023
DOI:https://doi.org/10.1103/PhysRevLett.130.151905
Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.
Published by the American Physical Society
Physics Subject Headings (PhySH)
Corrections
27 June 2023
Correction: The omission of the fourth author (S. Ahmed) has been fixed.