2002/10/21 by E. Oset, J. R. Peláez, J. R. Pelaez +1 · 2 citations
Physics and Astronomy · #Chiral perturbation theory #Context (archaeology) #High-Energy Particle Collisions Research #Meson #Nuclear physics #Particle physics #Particle physics theoretical and experimental studies #Physics #Pion #Quantum Chromodynamics and Particle Interactions #Resonance (particle physics) #Unitarity #Vector meson #Vector meson dominance #hep-ph #nucl-th
paper · pdf · doi:10.1103/physrevd.67.073013
published as Phys.Rev. D67 (2003) 073013 · 15 pages, 10 figures, published version
openalex publication_date 2002/10/21 · arxiv created 2003/05/02 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Together with the VMD dominant terms for \η \→ \π0 \γ \γ, we introduce the contribution of chiral loops from unitarized chiral perturbation theory, thus generating the a0(980) resonance and fixing the longstanding sign ambiguity on its contribution to this process. The same approach allows us to establish constraints in the decay from the \γ \γ \→ \π0 \η data. In particular, the \η VV couplings have to be reduced to agree with the experimental V \→ \η \γ partial decay widths. We obtain for the \η \→ \π0 \γ \γ decay width 0.47\± 0.10 eV, which is in remarkable agreement with the most recent experimental measurement.