Rare meson decays into very light neutralinos

TL;DR

This paper calculates rare meson decay rates into very light neutralinos, showing these processes are highly suppressed in the MSSM with minimal flavor violation, and that current experiments do not constrain neutralino mass.

Contribution

It provides the first complete calculation of loop-induced meson decays into light neutralinos within the MSSM framework.

Findings

Branching ratios are strongly suppressed in the MSSM.

No experimental bounds on neutralino mass can be derived.

A massless neutralino remains allowed by current data.

Abstract

Results are presented for the two-body decays of mesons into light neutralinos and from the first complete calculation of the loop-induced decays of kaons to pions plus light neutralinos and of B mesons to kaons plus light neutralinos. The branching ratios are shown to be strongly suppressed within the MSSM with minimal flavor violation, and no bounds on the neutralino mass can be inferred from experimental data, i.e. a massless neutralino is allowed.