Significance of 1/2− and excited 1/2+ resonance octets in semileptonic hyperon decays

Ascertain whether the contributions of the negative-parity spin-1/2 baryon octet (including N(1535), Λ(1670), Σ(1680), and Ξ(1810)) and the excited positive-parity spin-1/2 Roper-like octet (including N(1440), Λ(1600), Σ(1660), and Ξ(1790)) have a significant impact on semileptonic hyperon decay amplitudes, beyond their demonstrated importance in non-leptonic hyperon decays, within frameworks based on relativistic baryon chiral perturbation theory and resonance saturation.

Background

The paper develops a relativistic next-to-leading order chiral perturbation theory description of non-leptonic hyperon decays and shows that including the 1/2− and (excited) 1/2+ resonance octets is crucial to simultaneously describe s- and p-wave amplitudes.

Given the pronounced role of these resonances in non-leptonic amplitudes, the authors highlight the unresolved question of whether similar resonance effects are also important in other observables, particularly semileptonic hyperon decays.

References

It remains to be seen if the influence of the resonance states, the $1/2-$ and the (excited) $1/2+$ octets, appears to be significant in other quantities such as semileptonic decay amplitudes.

— Hyperon non-leptonic decays in relativistic Chiral Perturbation Theory with resonances  (2604.00646 - Salone et al., 1 Apr 2026) in Section 5 (Conclusion and outlook)