Indirect detection of dark matter absorption in the Galactic Center

TL;DR

This paper proposes a novel method for detecting dark matter by observing nuclear excitations in the Galactic Center, which emit detectable gamma-ray photons, and assesses the potential of current and future gamma-ray telescopes to constrain dark matter properties.

Contribution

It introduces a new indirect detection channel via nuclear absorption of dark matter and provides calculations and projections for experimental sensitivities in the MeV range.

Findings

Nuclear excitation by dark matter is highly sensitive to dark matter mass.

Future gamma-ray telescopes could improve constraints on dark matter-nucleus coupling by an order of magnitude.

The method offers a complementary approach to traditional dark matter searches.

Abstract

We consider the nuclear absorption of dark matter as an alternative to the typical indirect detection search channels of dark matter decay or annihilation. In this scenario, an atomic nucleus transitions to an excited state by absorbing a pseudoscalar dark matter particle and promptly emits a photon as it transitions back to its ground state. The nuclear excitation of carbon and oxygen in the Galactic Center would produce a discrete photon spectrum in the $\mathcal{O}(10)$ MeV range that could be detected by gamma-ray telescopes. Using the \texttt{BIGSTICK} large-scale shell-model code, we calculate the excitation energies of carbon and oxygen. We constrain the dark matter-nucleus coupling for current COMPTEL data, and provide projections for future experiments AMEGO-X, e-ASTROGAM, and GRAMS for dark matter masses from $\sim$ 10 to 30 MeV. We find the excitation process to be very sensitive to the dark matter mass and find that the future experiments considered would improve constraints on the dark matter-nucleus coupling within an order of magnitude.