Coupled-channel analysis of the near-threshold e + e − → N N ¯ cross sections
Year: 2025
Type: article
Abstract: The possible existence of nucleon-antinucleon bound states has been studied for decades. We investigate the e + e − → p p ¯ and e + e − → n n ¯ cross sections in the nonrelativistic effective field theory framework. The proton-antiproton and neutron-antineutron coupled-channel final state interactions are considered and found responsible for near-threshold enhancements. Both the proton-neutron mass difference and the Coulomb interaction between p and p ¯ are considered, and the N N ¯ strong interactions are taken into account through a short-distance optical potential. By fitting the low energy constants in the amplitudes to the data for the near-threshold e + e − → N N ¯ cross sections from the BESIII and SND collaborations, a N N ¯ quasibound state is found just above the p p ¯ threshold, and another N N ¯ pole is found on the unphysical Riemann sheet, farther away from the threshold. The constructed coupled-channel amplitude with Coulomb effects also offers a framework that can be used directly in experimental analyses on fine structures near the N N ¯ thresholds.
Authors: Zhao-Sai Jia, Zhen-Hua Zhang, Feng-Kun Guo, Gang Li
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: hybrid
OpenAlex ID: W4408447103