Constraints on $s\to d \gamma$ from Radiative Hyperon and Kaon Decays

TL;DR

This paper uses data from radiative hyperon and kaon decays to set new limits on potential new physics interactions affecting the quark-level $s o d \gamma$ transition, complementing existing constraints from $b o s \gamma$ decays.

Contribution

It introduces a method to extract constraints on new interactions by separating short and long distance contributions in radiative hyperon and kaon decays.

Findings

Constraints on new interactions from hyperon decays.

Constraints on new interactions from kaon decays.

Method to distinguish short and long distance effects.

Abstract

The quark-level process $b \to s \gamma$ has been used extensively to place constraints on new interactions. These same interactions can be further constrained from the enhancement they induce in the quark-level $s \to d \gamma$ transition, to the extent that the short distance contributions can be separated from the long distance contributions. We parameterize what is known about the long distance amplitudes and subtract it from the data in radiative hyperon and kaon decays to constrain new interactions.