π0, η, η' → γγ Decays and the Explicit Chiral Symmetry Breaking

2023/08/01 by A. A. Osipov · 1 voice
Physics and Astronomy · #Quantum Chromodynamics and Particle Interactions #Particle physics theoretical and experimental studies #Black Holes and Theoretical Physics

paper · pdf · doi:10.1134/s0021364023602269

openalex publication_date 2023/08/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/06/13

Abstract

Corrections to the Wess–Zumino–Witten anomaly caused by the explicit breaking of the SU(3) × SU(3) chiral symmetry are studied using the effective meson Lagrangian based on the Nambu–Jona-Lasinio model with the simultaneous expansion in derivatives, current quark masses, and 1/ N c powers. The leading contribution and the first correction for the amplitudes of the π 0 , η, η' → γγ decays and the contact term in the η /η \kern 1pt ' → π ⁺ π ^- γ amplitudes have been calculated. The results are compared with similar 1/ N c chiral perturbation calculations and existing experimental data.

Citations

• Review of Particle Physics
• Precision measurement of the neutral pion lifetime

Discussions

• The initial valence quark assignment for the neutral pion came from the quark model, but the best direct experimental constraint on the quark content of the $\pi^0$ probably comes from its measured tw [stackexchange, 1 points]

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