Probing right-handed neutrinos dipole operators

TL;DR

This paper explores the potential to detect dipole interactions between right-handed neutrinos in a minimal see-saw model at future experiments, reviewing current bounds and future prospects.

Contribution

It introduces the study of dipole operators between sterile neutrinos in a minimal see-saw model and assesses their testability at upcoming long-lived particle experiments.

Findings

Current bounds on dipole interactions from experiments and astrophysics.

Future experiments could detect the decay $N_2 o N_1 \gamma$ induced by the dipole.

The paper highlights the potential of upcoming facilities to probe these interactions.

Abstract

We consider the minimal see-saw extension of the Standard Model with two right-handed singlet fermions $N_{1,2}$ with mass at the GeV scale, augmented by an effective dipole operator between the sterile states. We firstly review current bounds on this effective interaction from fixed-target and collider experiments as well as from astrophysical and cosmological observations. We then highlight the prospects for testing the decay $N_2 \to N_1 \gamma$ induced by the dipole at future facilities targeting long lived particles such as ANUBIS, CODEX-b, FACET, FASER 2, MAPP and SHiP.