Progress on the exploratory calculation of the rare Hyperon decay $\Sigma^+ \to p \ell^+ \ell^-$

TL;DR

This paper reports progress on the first exploratory lattice calculation of the long-distance form factors for the rare Hyperon decay $ ext{Sigma}^+ o p ext{l}^+ ext{l}^-$, aiming to refine Standard Model predictions and detect potential new physics.

Contribution

It presents initial lattice QCD calculations of the decay's form factors, improving theoretical predictions for this rare process.

Findings

Progress towards calculating decay form factors

Use of domain-wall fermions on a 340 MeV pion mass ensemble

Advancement in theoretical understanding of hyperon decay

Abstract

The rare Hyperon decay $\Sigma^+ \to p \ell^+ \ell^-$ is an $s \to d$ flavour changing neutral current process, which is highly suppressed within the Standard Model, and is therefore sensitive to new physics. Due to recent improvements in experimental measurements of this decay, the Standard Model theory prediction must also be improved in order to identify any new physics in this channel. We present updates on our progress towards the first exploratory lattice calculation of the long-distance part of the form factors of this decay. This pilot calculation is performed on a 340 MeV pion mass ensemble using domain-wall fermions as part of the RBC-UKQCD collaboration.