# Comments on a Massless Neutralino

## TL;DR

This paper explores the theoretical and experimental implications of a very light, potentially massless neutralino, analyzing collider data, electroweak precision tests, and astrophysical constraints to assess its viability.

## Contribution

It provides a comprehensive analysis demonstrating that a massless neutralino remains consistent with current collider, electroweak, astrophysical, and cosmological observations.

## Key findings

- A massless neutralino is compatible with existing data.
- Collider phenomenology of a very light neutralino is thoroughly examined.
- Astrophysical and cosmological constraints do not exclude a massless neutralino.

## Abstract

We consider first an interesting connection between the development of physics and the Boston Red Sox. We then discuss in detail the collider phenomenology, as well as precision electroweak observables of a very light neutralino. We conclude by considering also the astrophysics and cosmology of a very light neutralino. We find that a massless neutralino is consistent with all present data.