INTEGRAL determines X-Ray Constraints on Dark Photon Tridents
A paper by Linden, Nguyen, and Tait (2024) used 16 years of INTEGRAL
data to investigate Dark Photon Dark Matter decay. This work studied
a process known as the dark-photon trident, where three-photon final
states are produced by the decay of a single dark photon. This result
provides world-leading constraints on the dark photon kinetic mixing
coupling with the Standard Model photon in the dark photon mass range
between 90-1022 keV, exceeding constraints from direct detection experiments
by four orders of magnitude above 150 keV. These results highlight the
importance of X-ray astronomy in terms of studying dark matter and beyond
standard model physics, and motivate future X-ray observations to look for
this unique decay signature.
This figure depicts the total x-ray flux from observation and compares the
results with our astrophysical models: The 16-year INTEGRAL data between
30-1022 keV are shown as black points. The red spectrum describes photons
up to 100 keV coming from unresolved point sources. The green power-law
spectrum models the inverse-Compton scattering of high-energy electrons
with interstellar radiation fields. The cyan spectrum fits positronium
emission produced by cooled cosmic-ray positrons that annihilate with
interstellar medium electrons, and which also produce the 511-keV line.
An additional line spectrum from 7Be is shown in orange around 478 keV.
The authors also include the dark photon trident spectrum in grey, with
an arbitrary normalization, which demonstrates the sensitivity of INTEGRAL
data in distinguishing this dark matter signal from conventional astrophysical
background models.
