UC Riverside darkish matter analysis program targets assumptions about particle physics.
As its identify suggests, darkish matter — materials which makes up about 85% of the mass in the universe — emits no gentle, eluding simple detection. Its properties, too, stay pretty obscure.
Now, a theoretical particle physicist at the College of California, Riverside, and colleagues have revealed a analysis paper in the Journal of Excessive Power Physics that reveals how theories positing the existence a brand new sort of power may assist clarify darkish matter’s properties.
“We stay in an ocean of darkish matter, but we all know little or no about what it could possibly be,” stated Flip Tanedo, an assistant professor of physics and astronomy and the paper’s senior creator. “It’s considered one of the most vexing identified unknowns in nature. We all know it exists, however we have no idea how to search for it or why it hasn’t proven up the place we anticipated it.”
Physicists have used telescopes, gigantic underground experiments, and colliders to be taught extra about darkish matter for the final 30 years, although no optimistic proof has materialized. The damaging proof, nonetheless, has compelled theoretical physicists like Tanedo to assume extra creatively about what darkish matter could possibly be.
The brand new analysis, which proposes the existence of an additional dimension in space-time to seek for darkish matter, is a part of an ongoing analysis program at UC Riverside led by Tanedo. In accordance to this concept, a few of the darkish matter particles don’t behave like particles. In impact, invisible particles work together with much more invisible particles in such a method that the latter stop to behave like particles.
“The aim of my analysis program for the previous two years is to lengthen the concept of darkish matter ‘speaking’ to darkish forces,” Tanedo stated. “Over the previous decade, physicists have come to respect that, in addition to darkish matter, hidden darkish forces could govern darkish matter’s interactions. These may utterly rewrite the guidelines for a way one ought to search for darkish matter.”
If two particles of darkish matter are attracted to, or repelled by, one another, then darkish forces are working. Tanedo defined that darkish forces are described mathematically by a concept with additional dimensions and seem as a continuum of particles that would handle puzzles seen in small galaxies.
“Our ongoing analysis program at UCR is an extra generalization of the darkish power proposal,” he stated. “Our noticed universe has three dimensions of area. We suggest that there could also be a fourth dimension that solely the darkish forces learn about. The additional dimension can clarify why darkish matter has hidden so effectively from our makes an attempt to research it in a lab.”
Tanedo defined that though additional dimensions could sound like an unique concept, they’re really a mathematical trick to describe “conformal area theories” — unusual three-dimensional theories which are extremely quantum mechanical. All these theories are mathematically wealthy, however don’t include typical particles and so are sometimes not thought-about to be related for describing nature. The mathematical equivalence between these difficult three-dimensional theories and a extra tractable additional dimensional concept is called the holographic precept.
“Since these conformal area theories have been each intractable and strange, they hadn’t actually been systematically utilized to darkish matter,” Tanedo added. “As a substitute of utilizing that language, we work with the holographic extra-dimensional concept.”
The important thing characteristic of the extra-dimensional concept is that the power between darkish matter particles is described by an infinite variety of totally different particles with totally different lots known as a continuum. In distinction, unusual forces are described by a single sort of particle with a hard and fast mass. This class of continuum-dark sectors is thrilling to Tanedo as a result of it does one thing “recent and totally different.”
In accordance to Tanedo, previous work on darkish sectors focuses totally on theories that mimic the conduct of seen particles. His analysis program is exploring the extra excessive sorts of theories that the majority particle physicists discovered much less fascinating, maybe as a result of no analogs exist in the actual world.
In Tanedo’s concept, the power between darkish matter particles is surprisingly totally different from the forces felt by unusual matter.
“For the gravitational power or electrical power that I educate in my introductory physics course, if you double the distance between two particles you cut back the power by an element of 4. A continuum power, on the different hand, is lowered by an element of up to eight.”
What implications does this additional dimensional darkish power have? Since unusual matter could not work together with this darkish power, Tanedo turned to the concept of self-interacting darkish matter, an concept pioneered by Hai-Bo Yu, an affiliate professor of physics and astronomy at UCR who is just not a coauthor on the paper. Yu confirmed that even in the absence of any interactions with regular matter, the results of those darkish forces could possibly be noticed not directly in dwarf spheroidal galaxies. Tanedo’s group discovered the continuum power can reproduce the noticed stellar motions.
“Our mannequin goes additional and makes it simpler than the self-interacting darkish matter mannequin to clarify the cosmic origin of darkish matter,” Tanedo stated.
Subsequent, Tanedo’s group will discover a continuum model of the “darkish photon” mannequin.
“It’s a extra practical image for a darkish power,” Tanedo stated. “Dark photons have been studied in nice element, however our extra-dimensional framework has a number of surprises. We can even look into the cosmology of darkish forces and the physics of black holes.”
Tanedo has been working diligently on figuring out “blind spots” in his group’s seek for darkish matter.
“My analysis program targets considered one of the assumptions we make about particle physics: that the interplay of particles is well-described by the trade of extra particles,” he stated. “Whereas that’s true for unusual matter, there’s no motive to assume that for darkish matter. Their interactions could possibly be described by a continuum of exchanged particles somewhat than simply exchanging a single sort of power particle.”
Reference: “Continuum-mediated self-interacting darkish matter” by Ian Chaffey, Sylvain Fichet and Philip Tanedo, 1 June 2021, Journal of Excessive Power Physics.
Tanedo was joined in the analysis by Ian Chaffey, a postdoctoral researcher working with Tanedo; and Sylvain Fichet, a postdoctoral researcher at the Worldwide Heart for Theoretical Physics – South American Institute for Elementary Analysis in Brazil.
The analysis was funded by the U.S. Division of Power.