Recasting Bounds on Long-lived Heavy Neutral Leptons in Terms of a Light Supersymmetric R-parity Violating Neutralino

TL;DR

This paper reinterprets experimental data to set new, significantly tighter bounds on R-parity-violating couplings of light neutralinos in supersymmetry, using existing searches for sterile neutrinos.

Contribution

It recasts sensitivity of past and present experiments to derive improved bounds on RPV couplings of light neutralinos in supersymmetric models.

Findings

Experiments like T2K, DUNE, and FASER can improve bounds by 3-4 orders of magnitude.

Light neutralinos can decay via RPV couplings, producing displaced vertices or missing energy signatures.

New bounds significantly constrain RPV parameter space for light neutralinos.

Abstract

In R-parity-violating (RPV) supersymmetric models, light neutralinos with masses from the GeV-scale down to even zero are still allowed by all laboratory constraints. They are further consistent with dark matter observations, as they decay via RPV couplings. These RPV couplings are in general constrained to be small. Hence, such light neutralinos, if produced, e.g., at a beam-dump or collider experiment, appear as displaced vertices or missing energy at the detector level. The same signatures have been extensively searched for at various experiments in the theoretical context of sterile neutrinos which mix with active neutrinos. In this work, we recast the sensitivity of both past and present experiments to sterile neutrinos to obtain new bounds on RPV couplings associated with a light neutralino. We find experiments such as T2K, BEBC, FASER, DUNE, and MoEDAL-MAPP can improve the current bounds on RPV couplings by up to $3-4$ orders of magnitude in several benchmark scenarios.