Scientists confirm a possible 5th force of nature

Research conducted by a Hungarian team last year that hinted at the discovery of a new type of light particle could unveil a fifth fundamental force of nature, scientists from the University of California, Irvine confirmed in a newly-published paper.

In mid-2015, a team of experimental nuclear physicists at the Hungarian Academy of Sciences were searching for so-called “dark photos,” particles that would make up the unseen substance known as dark matter that experts believe is responsible for the majority of the universe’s mass, when they discovered a radioactive decay anomaly that hinted at a possible new particle.

This particle would be just 30 times heavier than an electron, but according to UCI physics and astronomy professor Jonathan Feng, the authors of that original study were unable to show that this particle represented a new force. “They simply saw an excess of events that indicated a new particle, but it was not clear to them whether it was a matter particle or a force-carrying particle,” Feng explained Monday in a statement released by the university.

He and his colleagues, who published their findings this week in the journal Physical Review Letters, reviewed that Hungarian group’s data as well as other, similar experiments, and found that the evidence supporting the existence of a fifth fundamental force – a breakthrough which Feng said would be “revolutionary” if validated.

“For decades, we’ve known of four fundamental forces: gravitation, electromagnetism, and the strong and weak nuclear forces,” the professor added. “If confirmed by further experiments, this discovery of a possible fifth force would completely change our understanding of the universe, with consequences for the unification of forces and dark matter.”

Findings suggest that there may be a separate group of dark forces

Data collected as part of the various experiments reviewed by the UCI team showed that it was unlikely that they had discovered dark photons. However, their analysis showed that the particles could instead be a “protophobic X boson.” While the normal electrical force acts on photons and electrons, this new boson interacts only with electrons and neutrons, they explained.

Co-author Timothy Tait, also a physics and astronomy professor at the university, said that there is “no other boson that we’ve observed that has this same characteristic,” and Feng added that it “is not very heavy, and laboratories have had the energies required to make it since the ’50s and ’60s. But the reason it’s been hard to find is that its interactions are very feeble.”

“Because the new particle is so light, there are many experimental groups working in small labs around the world that can follow up the initial claims, now that they know where to look,” Feng noted, emphasizing that he is particularly intrigued by the possibility that this possible fifth force of nature could be associated with the electromagnetic and nuclear forces as “manifestations of one grander, more fundamental force.”

Furthermore, based on the currently understanding of the standard model, he and his colleagues believe that there could be a separate dark sector with its own matter and forces, and that the two sectors interact with one another through a difficult-to-detect series of fundamental interactions. The dark sector force, he speculates, “may manifest itself as this protophobic force we’re seeing as a result of the Hungarian experiment.”

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Image credit: NASA