The π f0(500) decay of the a1(1260)

We evaluate the a(1)(1260) -> pi sigma(f(0)(500)) decay width from the perspective that the a(1)(1260) resonance is dynamically generated from the pseudoscalar-vector interaction and the sigma arises from the pseudoscalar-pseudoscalar interaction. A triangle mechanism with a(1)(1260) -> p pi followed by rho -> pi pi and a fusion of two pions within the loop to produce the sigma provides the mechanism for this decay under these assumptions for the nature of the two resonances. We obtain widths of the order of 13-22 MeV. Present experimental results differ substantially from each other, suggesting that extra efforts should be devoted to the precise extraction of this important partial decay width, which should provide valuable information on the nature of the axial vector and scalar meson resonances and help clarify the role of the ps channel in recent lattice QCD calculations of the a(1).

Automated summary

The study evaluates the decay width of a(1)(1260) -> pi sigma(f(0)(500)), providing detailed explanations of the assumptions about the properties of the two resonances and the decay mechanism. Current experimental results show significant differences, indicating the need for additional efforts to accurately extract this important partial decay width.