Snowmass2021 Cosmic Frontier White Paper: Puzzling Excesses in Dark Matter Searches and How to Resolve Them

TL;DR

This white paper reviews various astrophysical and terrestrial excess signals potentially linked to dark matter, discusses their possible origins, and proposes strategies to resolve these anomalies in future research.

Contribution

It provides a comprehensive overview of current excess signals in dark matter searches and outlines actionable steps to clarify their nature and origin.

Findings

Multiple excess signals observed across different experiments.

Potential dark matter interpretations of these excesses.

Proposed experimental and theoretical approaches to resolve ambiguities.

Abstract

Intriguing signals with excesses over expected backgrounds have been observed in many astrophysical and terrestrial settings, which could potentially have a dark matter origin. Astrophysical excesses include the Galactic Center GeV gamma-ray excess detected by the Fermi Gamma-Ray Space Telescope, the AMS antiproton and positron excesses, and the 511 and 3.5 keV X-ray lines. Direct detection excesses include the DAMA/LIBRA annual modulation signal, the XENON1T excess, and low-threshold excesses in solid state detectors. We discuss avenues to resolve these excesses, with actions the field can take over the next several years.