Last year, Hungarian physicists published a paper that suggested the evidence of a fifth force of nature but didn't create much hype.
A recent data analysis from the University of California, Irvine researchers said it could very well be the proof of the so-called fifth force.
Scientists use the particle physics' Standard Model to explain all the observable physics. The model's main forces include electromagnetism, gravity and the weak and strong nuclear forces.
This Standard Model is unable to explain the so-called dark matter. This is why scientists continued to search for other possible forces, including the fifth force.
The Hungarian Study
Research leader, physicist Attila Krasznahorkay, and his team were searching for dark matter in the Hungarian study last year.
When they fired protons at a lithium-7, it produced beryllium-8 nuclei whose behavior hinted of the fifth force.
When beryllium-8 nuclei decay, they produce several electrons-positrons pairs. Based on the Standard Model, the abundance of these pairs should decrease as the electron and positron start to separate from each other as the trajectory angle increases.
In the Hungarian experiment, the number of pairs surged when the electron-positron trajectory angle reached 140 degrees. This created a small "bump" before the angle increased again and the number of pairs decreased.
This bump was highlighted as proof of a new particle bearing a unique force.
American Analysis
According to the American team led by Jonathan Feng, the bump is proof of a protophobic X boson. The new particle's behavior could be the evidence of the elusive fifth force.
The unexpected discovery still leaves many particle physicists unconvinced. To date, no teams have successfully replicated the Hungarian experiment. Moreover, gathering the same particles can be a challenge.
"It certainly isn't the first thing I would have written down if I were allowed to augment the standard model at will. Perhaps we are seeing our first glimpse into physics beyond the visible Universe," said Massachusetts Institute of Technology (MIT) theoretical physicist Jesse Thaler.
Various groups of researchers in the United States and Europe are working on ways on how to validate the Hungarian experiment, including the group at the Thomas Jefferson National Accelerator Facility in Virginia.
The Hungarian experiment was published in the Physical Review Letters. The recent American analysis was published in the pre-print site arXiv.
