Zooming in on Axions

The latest results from a search for QCD axions from the Sun as well as axion-like particles of solar and dark matter origins were presented by Dr. Michelle Galloway from the University of Zurich on June 26th at the “Zooming in on Axions in the Early Universe” workshop hosted by CERN. With an unprecedented low background of 76 ± 2 stat events/(tonne × year × keV) between 1–30 keV, XENON1T is uniquely poised to explore new parameter space for these electronic-recoil channels via the axio-electric effect. Our search revealed an excess of events in the (1 – 7) keV region, favoring these channels over background with significances of 3.5 sigma for solar axions/ALPs and 3.0 sigma global (4.0 local) for ALP dark matter with a peak at 2.3 +- 0.2 keV (68% C.L.). The talk reviewed the detection principles, cross checks of our results, discrepancy with stellar constraints, and presented a hypothesis of a new background from a previously undetected tritium component. Presentation materials can be found here.