Theoretical physicists confirm the possible discovery of the fifth fundamental force of nature | Physics

Recent findings from a team of experimental nuclear physicists in Hungary pointing to the possible discovery of a new subatomic particle could be evidence of a fifth force of nature, according to a team of theoretical physicists from the University of California, Irvine .

The discovery of a possible fifth force of nature would completely change our understanding of the Universe, according to Jonathan L. Feng et al. This Hubble image shows the Whirlpool galaxy (also known as Messier 51 and NGC 5194) and its companion galaxy, NGC 5195. Image credit: NASA/ESA/S. Beckwith, STScI/Hubble Heritage Team/STScI/AURA.

“If it’s true, it’s revolutionary. For decades, we have known four fundamental forces: gravitation, electromagnetism, and the strong and weak nuclear forces,” said Professor Jonathan Feng, Professor of Physics and Astronomy in the Department of Physics and Astronomy at the Institute. University of California at Irvine. .

“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.”

The team came across a recent study by Dr. Attila Krasznahorkay of the Institute for Nuclear Research of the Hungarian Academy of Sciences in Debrecen, Hungary, and co-authors (preprint who were looking for “dark photons,” particles that would signify invisible dark matter, which physicists say makes up about 85% of the mass of the Universe.

The work of A. Krasznahorkay et al discovered a radioactive decay anomaly that indicates the existence of a light particle barely 30 times heavier than an electron.

“The experimenters could not claim that it was a new force. They just saw an excess of events that indicated a new particle, but it wasn’t clear to them whether it was a matter particle or a force-carrying particle,” said Prof. Feng.

Professor Feng and his colleagues studied the data from the Hungarian team as well as all other previous experiments in this area and showed that the evidence strongly favors both matter particles and dark photons.

They came up with a new theory, however, that synthesized all of the existing data and determined that the discovery could indicate a fifth force.

Their the initial analysis was published on April 25 on the preprint server, and this month in the newspaper Physical examination letters. A follow-up document amplifying the conclusions of the initial work was published on August 11 on

The analysis demonstrates that instead of being a dark photon, the particle may be a ‘protophobic X boson’.

While the normal electric force acts on electrons and protons, this new particle only interacts with electrons and neutrons – and to an extremely limited range.

“There is no other boson that we have observed that has this same characteristic. Sometimes we just call it the ‘X boson’, where ‘X’ stands for unknown,” said co-author Professor Timothy Tait.

“Other experiences are crucial. The particle is not very heavy, and labs have had the energies to make it since the 1950s and 60s,” Professor Feng added.

“But the reason he’s been hard to find is because his interactions are very weak.”

“That said, because the new particle is so light, there are many experimental groups working in small labs around the world who can follow the initial claims, now that they know where to look.”

Like many scientific breakthroughs, this one opens up entirely new fields of research.

One direction that intrigues scientists is the possibility that this potential fifth force can be joined to the strong and weak electromagnetic and nuclear forces as manifestations of a larger, more fundamental force.

Citing physicists’ understanding of the Standard Model, Professor Feng speculated that there could also be a separate dark sector with its own matter and forces.

“It is possible that these two sectors are talking to and interacting with each other through somewhat veiled but fundamental interactions,” Professor Feng said.

“This dark sector force can manifest as this protophobic force that we see as a result of the Hungarian experience.”

“In a broader sense, this ties in with our original research to understand the nature of dark matter.”


Jonathan L.Feng et al. 2016. Protophobic interpretation of the fifth force of the anomaly observed in 8Be nuclear transitions. Phys. Reverend Lett. 117 (7): 071803; doi: 10.1103/PhysRevLett.117.071803

Jonathan L.Feng et al. 2016. Particle Physics Models for the 17 MeV Anomaly in Beryllium Nuclear Decays. arXiv: 1608.03591

A.J. Krasznahorkay et al. 2016. Observing the creation of anomalous internal pairs in 8Being: a possible indication of a light, neutral boson. Phys. Reverend Lett. 116 (4): 042501; doi: 10.1103/PhysRevLett.116.042501

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