Study of the reactions n p → 2π⁺π^-, 2π⁺π^-π⁰, and 2π⁺π^-2π⁰ using J/ψ→ p π^-n

2025/11/26 by BESIII Collaboration, M. Ablikim, М. Н. Ачасов +784
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Experiment (hep-ex) #Nuclear physics research studies #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions

paper · pdf · doi:10.48550/arxiv.2511.21462

openalex publication_date 2025/11/26 · openalex created_date 2025/11/28 · openalex updated_date 2026/07/28

Abstract

We report an experimental investigation of the reactions n p → 2π⁺π^-, n p → 2π⁺π^-π⁰, and n p → 2π⁺π^-2π⁰ using (10.087 ± 0.044) × 10⁹ J/ψ events collected with the BESIII detector at the BEPCII storage ring. The antineutron (n) is produced in the decay J/ψ→ p π^- n with studied momentum from 200~MeV/c to 1174~MeV/c, while the target proton originates from the hydrogen nuclei in the cooling oil of the beam pipe. This novel method pioneers the study of n-nucleon interactions at an e⁺e^- collider, providing the first experimental data for n momenta exceeding 800~MeV/c.

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