# The DAMPE excess and gamma-ray constraints

## TL;DR

This paper examines dark matter explanations for the DAMPE cosmic-ray excess, analyzing gamma-ray constraints and showing that current observations challenge these hypotheses.

## Contribution

It provides a comprehensive analysis of gamma-ray constraints on dark matter models proposed to explain the DAMPE excess, highlighting tensions with observational data.

## Key findings

- DM explanations conflict with Fermi-LAT diffuse gamma-ray background
- Nearby subhalo scenario constrained by Fermi-LAT, MAGIC, and HESS surveys
- Gamma-ray constraints broadly rule out DM interpretations of the DAMPE excess

## Abstract

The direct measurements of the cosmic electron-positron spectrum around 1 TeV made by DAMPE have induced many theoretical speculations about possible excesses in the data above the standard astrophysical predictions that might have the dark matter (DM) origin. These attempts mainly fall into two categories: i) DM annihilation (or decay) in the Galactic halo producing the broad spectrum excess; ii) DM annihilation in the nearby compact subhalo producing the sharp peak at 1.4 TeV. We investigate the gamma-ray emission accompanying $e^+e^-$ production in DM annihilation, as well as various theoretical means to suppress the prompt radiation, such as specific interaction vertices or multi-cascade modes, and conclude that these attempts are in tension with various gamma-ray observations. We show that the DM explanations of the broad spectrum excess tend to contradict the diffuse isotropic gamma-ray background (IGRB), measured by Fermi-LAT, while the nearby subhalo scenario is constrained by nonobservation in the surveys, performed by Fermi-LAT, MAGIC and HESS. We also briefly review other types of gamma-ray constraints, which seem to rule out the DM interpretations of the DAMPE broad spectrum excess as well.