For decades, we've known about the existence of four fundamental forces of nature: gravity, electromagnetism, and the strong and weak nuclear forces. Now recent study of the possible discovery of a previously unknown subatomic particle suggests there may be a fifth force. As usual, more research is needed to confirm the finding but if it gets confirmed by further experiments it will be a revolutionary finding.
The UCI work 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 newfound boson interacts only with electrons and neutrons - and at an extremely limited range. Analysis co-author Timothy Tait, professor of physics & astronomy, said, "There's no other boson that we've observed that has this same characteristic. Sometimes we also just call it the 'X boson,' where 'X' means unknown."
Feng noted that further experiments are crucial. "The particle is not very heavy, and laboratories have had the energies required to make it since the '50s and '60s," he said. "But the reason it's been hard to find is that its interactions are very feeble. That said, 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."