Hunting for Dark Photon-Photon Tridents

TL;DR

This paper uses 16 years of x-ray data from INTEGRAL/SPI to set new constraints on dark photon decay, significantly narrowing the viable parameter space for dark photon dark matter models.

Contribution

It provides the first comprehensive analysis incorporating full one-loop decay amplitudes and advanced background modeling to improve constraints on dark photon properties.

Findings

Established world-leading constraints on kinetic mixing for 61-1022 keV dark photons.

Demonstrated the potential of x-ray observatories to explore new dark photon parameter space.

Highlighted future prospects with next-generation x-ray instruments.

Abstract

Dark photons, hypothesized to be sufficiently light and/or weakly interacting, offer a compelling candidate for dark matter. Their decay into three photons, referred to as the "dark photon trident" process, becomes the dominant channel when the dark photon mass lies below the electron pair production threshold. This decay channel produces a significant flux of x-rays, presenting an opportunity for indirect detection. In this study, we analyze 16 years of x-ray data from INTEGRAL/SPI to investigate sub-MeV dark photon decay. By incorporating state-of-the-art astrophysical background modeling and accounting for the full one-loop decay amplitude, we achieve world-leading constraints on the kinetic mixing parameter for dark photon masses in the range of 61-1022 keV. These results represent a significant improvement over previous constraints, narrowing the parameter space for viable dark photon dark matter models. Furthermore, our findings highlight the potential of x-ray observatories to probe unexplored regions of parameter space and pave the way for future searches using next-generation instruments designed to detect faint astrophysical signals.