Scientists at the Institute for Nuclear Research at the Hungarian Academy of Sciences (Atomki) have posted findings showing what could be an example of that fifth force at work. The scientists were closely watching how an excited helium atom emitted light as it decayed. The particles split at an unusual angle — 115 degrees — which couldn’t be explained by known physics. The study’s lead scientist, Attila Krasznahorkay, told that this was the second time his team had detected a new particle, which they call X17, because they calculated its mass at 17 megaelectronvolts.
“X17 could be a particle, which connects our visible world with the dark matter,” he said in an email. When an electron returns to its lowest orbital, or “decays”, some of its energy is released in the form of smaller particles or photons of light. Scientists can measure the angles at which those particles or photons are emitted and use the data to study the forces governing the process. There are four fundamental forces – gravity, electromagnetism, the weak nuclear force, and the strong force – currently known to exist. Krasznahorkay’s team’s result comes three years after they published a similar finding from an experiment conducted with another type of atom named beryllium-8.
Fellow scientists assumed the results must be a mistake, but have been unable to find any mistakes in the team’s work or in the way the experiment was conducted. Geraint Lewis, a professor of astrophysics at the University of Sydney told: “What it’s telling us if it is correct is that there is something going on in the way that one particle talks to another particle that we haven’t got inside our mathematics at the moment.”
Jonathan Feng, a professor of physics and astronomy at the University of California, Irvine, told CNN that, if the observations are correct, the chances they are the result of something other than particle X17, and a fifth force, are one in a trillion.