Perspectives for Detection of a Higgsino-like Relic Neutralino

TL;DR

This paper explores the detection prospects of a Higgsino-like relic neutralino, analyzing its properties across parameter space and comparing theoretical predictions with experimental sensitivities, highlighting challenges and promising detection avenues.

Contribution

It provides a comprehensive analysis of relic Higgsino-like neutralino properties and evaluates experimental detection prospects, emphasizing the need for improved sensitivities and identifying promising indirect detection methods.

Findings

Detection of relic neutralinos requires significant experimental sensitivity improvements.

Neutrino flux measurements from Earth's center could probe certain parameter regions.

Cosmic ray antiproton/proton ratios offer promising detection prospects.

Abstract

It has been conjectured by Ambrosanio, Kane, Kribs, Martin and Mrenna (AKM) that the CDF event $p \bar p \to e^+ e^- \gamma \gamma + missing E_T$ is due to a decay chain involving two neutralino states (the lightest and the next-to-lightest ones). The lightest neutralino ($\chi_{AKM}$) has been further considered by Kane and Wells as a candidate for cold dark matter. In this paper we examine the properties of relic $\chi_{AKM}$'s in their full parameter space, and examine the perspectives for detection by comparing theoretical predictions to sensitivities of various experimental searches. We find that for most regions of the parameter space the detectability of a relic $\chi_{AKM}$ would require quite substantial improvements in current experimental sensitivities. The measurements of neutrino fluxes from the center of the Earth and of an excess of $\bar{p}/p$ in cosmic rays are shown to offer some favorable perspectives for investigating a region of the $\chi_{AKM}$ parameter space around the maximal $\tan \beta$ value allowed by the model.