LINK: Has a New, Fifth Force of Nature Been Found?

The new work by Feng and his team suggests that the Hungarians found not
a “dark photon” but rather a “protophobic X boson” — a strange particle
whose existence could indicate a fifth force of nature. The known
electromagnetic force acts on protons and electrons, but this newfound
particle apparently interacts only with protons and neutrons, and then
only at very short distances, researchers said.