Magic Zeroes and Hidden Symmetries

TL;DR

This paper investigates hidden symmetries causing 'magic zeroes' in particle physics, revealing how certain suppressed quantities can be explained by obscure symmetry mechanisms, with implications for the Standard Model and beyond.

Contribution

It identifies the hidden symmetry behind a recently discovered magic zero in muon dipole moments and introduces tools like spurion analysis and non-renormalization theorems for uncovering such symmetries.

Findings

Identified the symmetry responsible for the muon dipole moment zero

Developed methods to detect hidden symmetries in particle interactions

Provided tools applicable to discovering new magic zeroes

Abstract

Selection rules arising from accidental or broken symmetries may be sufficiently obscure that their agency is hidden, leading to the appearance of "magic zeroes" -- quantities that are suppressed without apparent recourse to a symmetry explanation. Magic zeroes and their corresponding hidden symmetries may shed new light on parametric hierarchies in the Standard Model and beyond. We identify the hidden symmetry responsible for a recently-discovered magic zero, the vanishing of the putative leading contribution to the anomalous dipole moments of the muon upon integrating out weak doublet and singlet vector-like fermions. Some of the tools involved -- spurion analysis leveraging discrete symmetries of the free theory, field redefinitions, spectator fields, and non-supersymmetric non-renormalization theorems -- may prove useful in the hunt for new magic zeroes and their hidden symmetries.