Coupled-channel analysis of the near-threshold $e^+e^-\to N\bar{N}$ cross sections

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Main Authors: Jia, Zhao-Sai, Zhang, Zhen-Hua, Guo, Feng-Kun, Li, Gang
Format: Preprint
Published: 2024
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author Jia, Zhao-Sai
Zhang, Zhen-Hua
Guo, Feng-Kun
Li, Gang
author_facet Jia, Zhao-Sai
Zhang, Zhen-Hua
Guo, Feng-Kun
Li, Gang
contents The possible existence of nucleon-antinucleon bound states has been studied for decades. We investigate the $e^+e^-\to p\bar{p}$ and $e^+e^-\to n\bar{n}$ 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 $\bar{p}$ are considered, and the $N\bar{N}$ 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 $e^+e^-\to N\bar{N}$ cross sections from the BESIII and SND Collaborations, a $N\bar{N}$ quasi-bound state is found just above the $p\bar{p}$ threshold, and another $N\bar{N}$ 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 $N\bar{N}$ thresholds.
format Preprint
id arxiv_https___arxiv_org_abs_2410_16873
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Coupled-channel analysis of the near-threshold $e^+e^-\to N\bar{N}$ cross sections
Jia, Zhao-Sai
Zhang, Zhen-Hua
Guo, Feng-Kun
Li, Gang
High Energy Physics - Phenomenology
High Energy Physics - Experiment
Nuclear Experiment
Nuclear Theory
The possible existence of nucleon-antinucleon bound states has been studied for decades. We investigate the $e^+e^-\to p\bar{p}$ and $e^+e^-\to n\bar{n}$ 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 $\bar{p}$ are considered, and the $N\bar{N}$ 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 $e^+e^-\to N\bar{N}$ cross sections from the BESIII and SND Collaborations, a $N\bar{N}$ quasi-bound state is found just above the $p\bar{p}$ threshold, and another $N\bar{N}$ 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 $N\bar{N}$ thresholds.
title Coupled-channel analysis of the near-threshold $e^+e^-\to N\bar{N}$ cross sections
topic High Energy Physics - Phenomenology
High Energy Physics - Experiment
Nuclear Experiment
Nuclear Theory
url https://arxiv.org/abs/2410.16873