Global fits of axion-like particles to XENON1T and astrophysical data

Understand

The excess of electron recoil events seen by the XENON1T experiment has been interpreted as a potential signal of axion-like particles (ALPs), either produced in the Sun, or constituting part of the dark matter halo of the Milky Way.

• It has also been explained as a consequence of trace amounts of tritium in the experiment.
• We consider the evidence for the solar and dark-matter ALP hypotheses from the combination of XENON1T data and multiple astrophysical probes, including horizontal branch stars, red giants, and white dwarfs.
• We briefly address the influence of ALP decays and supernova cooling.