A team of researchers jointly affiliated with Berkeley Lab’s Particle Theory Group and the Berkeley Center for Theoretical Physics has demonstrated that an upcoming telescope could be the discovery instrument for the particle nature of dark matter.

The research team – including Nick Rodd and Linda Xu, researchers in Berkeley Lab’s Physics Division, and Ben Safdi, a faculty member in UC Berkeley’s Physics Department – has been collaborating for several years looking for new ways to discover the elusive nature of dark matter. Their current study focuses on higgsino dark matter, a theoretical scenario where dark matter is a heavier version of the Higgs particle, with a mass of ~1 TeV or roughly 10 times heavier than the Higgs and 1,000 times heavier than a proton.

“The higgsino is arguably one of the most likely possibilities for what could make up the dark matter of our Universe,” says Rodd. “As a cousin of the Higgs, we know how the higgsino should interact with other particles and itself. In fact, when two higgsino particles collide, they should explode into a burst of energy including gamma-rays that would faintly illuminate the night sky. However, the illumination is computed to be extremely faint, and the challenge of detecting this faint light has long been thought to be out of reach of even the most promising future telescopes.”

Building on their 2020 study – which analyzed signals from the decay of sterile neutrinos, a lighter form of dark matter with a mass of only around 10 keV – the team studied how a faint signature of higgsino collisions could emerge from the center of our own Milky Way galaxy. Using state-at-of-art predictions for how dark matter is distributed in our galaxy, they showed that the gamma-ray signal predicted from the higgsino could be detected using the upcoming Cherenkov Telescope Array Observatory (CTAO).

As part of the current study, the team tested a wide set of instruments, and CTAO emerged as the most promising prospect. “We’re incredibly excited,” said Xu, who added that “the higgsino has been an elusive golden target for so long, and CTA has the right set of experimental attributes to finally be sensitive to this kind of light.”

According to Rodd, “The higgsino is one of our last chances to discover a class of dark matter candidates called WIMPs that we have chased for decades. What we’ve realized is that the CTAO will be a milestone for dark matter in either scenario: it will either discover the higgsino, which would finally tell us the nature of dark matter, or it will largely close this chapter in the search for dark matter and push us towards other directions as we continue to search for the answer to one of the biggest mysteries in physics.”

Read More:
CTA and SWGO can Discover Higgsino Dark Matter Annihilation
May 21, 2024 / Nicholas L. Rodd, Benjamin R. Safdi, and Weishuang Linda Xu / arXiv