Perspective of monochromatic gamma-ray line detection with the High Energy cosmic-Radiation Detection (HERD) facility onboard China's Space Station

TL;DR

HERD, a proposed space-based detector on China's space station, is highly capable of detecting monochromatic gamma-ray lines between 10 and a few hundred GeV, aiding dark matter research.

Contribution

This work demonstrates HERD's potential sensitivity to gamma-ray lines through simulations, highlighting its role in dark matter detection at space-based energies.

Findings

HERD will be among the most sensitive instruments for gamma-ray line detection from 10 to a few hundred GeV.

HERD's capabilities surpass many existing detectors in this energy range.

A significant portion of supersymmetric dark matter parameter space can be probed by HERD.

Abstract

HERD is the High Energy cosmic-Radiation Detection instrument proposed to operate onboard China's space station in the 2020s. It is designed to detect energetic cosmic ray nuclei, leptons and photons with a high energy resolution ($\sim1\%$ for electrons and photons and $20\%$ for nuclei) and a large geometry factor ($>3\,{ m^2\,sr}$ for electrons and diffuse photons and $>2\,{ m^2\,sr}$ for nuclei). In this work we discuss the capability of HERD to detect monochromatic $\gamma$-ray lines, based on simulations of the detector performance. It is shown that HERD will be one of the most sensitive instruments for monochromatic $\gamma$-ray searches at energies between $\sim10$ to a few hundred GeV. Above hundreds of GeV, Cherenkov telescopes will be more sensitive due to their large effective area. As a specific example, we show that a good portion of the parameter space of a supersymmetric dark matter model can be probed with HERD.