Evidence for Δ(2200)7/2^- from photoproduction and consequence for chiral-symmetry restoration at high mass

2015/03/19 by A. V. Anisovich, Anisovich, A. V., Volker Burkert +15
Physics and Astronomy · #FOS: Physical sciences #High-Energy Particle Collisions Research #Nuclear Experiment (nucl-ex) #Nuclear Theory (nucl-th) #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions

paper · pdf · doi:10.48550/arxiv.1503.05774

openalex publication_date 2015/03/19 · openalex created_date 2019/06/27 · openalex updated_date 2026/07/28

Abstract

We report a partial-wave analysis of new data on the double-polarization variable E for the reactions γp→ π⁺ n and γp→ π⁰ p and of further data published earlier. The analysis within the Bonn-Gatchina (BnGa) formalism reveals evidence for a poorly known baryon resonance, the one-star Δ(2200)7/2^-. This is the lowest-mass Δ^* resonance with spin-parity J^P=7/2^-. Its mass is significantly higher than the mass of its parity partner Δ(1950)7/2⁺ which is the lowest-mass Δ^* resonance with spin-parity J^P=7/2⁺. It has been suggested that chiral symmetry might be restored in the high-mass region of hadron excitations, and that these two resonances should be degenerate in mass. Our findings are in conflict with this prediction.

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