The s → d γ Transition in Kaon and Hyperon Decays

Original · EN

We survey the possibilities of detecting the s → d γ transition in kaon and hyperon radiative decays. In the more frequent decays, like K+ → π+ πᵒ γ, K+ → π+ ℓ+ ℓ-, the short-distance contribution is obscured by various long-distance transitions. Among the hyperon radiative decays, Ξ- → Σ- γ and Ω- → Ξ- γ are the leading candidates for providing a window to the short-distance s → d γ. The long-distance s → d γ transitions are also analyzed; their magnitude depends on the size of the deviation from a sum-rule among couplings of vector mesons to photons. The measurement of Ω- → Ξ- γ could provide information on the relative size of the short and long-distance contributions to the magnetic component of s → d γ.