The PAMELA and ATIC Excesses From a Nearby Clump of Neutralino Dark Matter

TL;DR

This paper proposes that a nearby dense clump of neutralino dark matter could explain the excess cosmic ray positron and electron signals observed by PAMELA and ATIC, fitting the data without conflicting with antiproton constraints.

Contribution

It introduces the idea that a local dark matter clump can account for the observed cosmic ray excesses, a novel explanation compared to uniform halo models.

Findings

A nearby neutralino clump can produce spectra matching PAMELA and ATIC data.

Such a clump can generate the required high annihilation rates.

The model remains consistent with antiproton flux constraints.

Abstract

In this letter, we suggest that a nearby clump of 600-1000 GeV neutralinos may be responsible for the excesses recently observed in the cosmic ray positron and electron spectra by the PAMELA and ATIC experiments. Although neutralino dark matter annihilating throughout the halo of the Milky Way is predicted to produce a softer spectrum than is observed, and violate constraints from cosmic ray antiproton measurements, a large nearby (within 1-2 kiloparsecs of the Solar System) clump of annihilating neutralinos can lead to a spectrum which is consistent with PAMELA and ATIC, while also producing an acceptable antiproton flux. Furthermore, the presence of a large dark matter clump can potentially accommodate the very large annihilation rate required to produce the PAMELA and ATIC signals.