University of California, Riverside | 2018 Jul 13
Researchers, including a UC Riverside particle physicist, interpret new experimental data aimed at showing dark matter interacts with ordinary matter — an unmet challenge in modern physics
An international team of scientists that includes University of California, Riverside, physicist Hai-Bo Yu has imposed conditions on how dark matter may interact with ordinary matter — constraints that can help identify the elusive dark matter particle and detect it on Earth.
Dark matter — nonluminous material in space — is understood to constitute 85 percent of the matter in the universe. Unlike normal matter, it does not absorb, reflect, or emit light, making it difficult to detect.
Physicists are certain dark matter exists, having inferred this existence from the gravitational effect dark matter has on visible matter. What they are less certain of is how dark matter interacts with ordinary matter — or even if it does.
In the search for direct detection of dark matter, the experimental focus has been on WIMPs, or weakly interacting massive particles, the hypothetical particles thought to make up dark matter.
But Yu’s international research team invokes a different theory to challenge the WIMP paradigm: the self-interacting dark matter model, or SIDM, a well-motivated framework that can explain the full range of diversity observed in the galactic rotation curves. First proposed in 2000 by a pair of eminent astrophysicists, SIDM has regained popularity in both the particle physics and the astrophysics communities since around 2009, aided, in part, by work Yu and his collaborators did. ...
Constraining Dark Matter Models with a Light Mediator at the PandaX-II Experiment - Xiangxiang Ren et al