Researchers continue to look for alternate forces of nature that might explain the presence of dark matter and the behavior of dark energy in the universe. Photo by UPI Photo/NASA | License Photo
IRVINE, Calif., May 26 (UPI) -- A team of Hungarian physicists published a paper last year hinting at the possibility of a fifth force of nature. It escaped publicity, but a recent analysis of the data by researchers at the University of California, Irvine has brought the paper back into the limelight.
The Standard Model of particle physics -- a model that helps scientists explain all the physics we can observe -- features four main forces: gravity, electromagnetism and the strong and weak nuclear forces. Scientists have long searched for -- and offered circumspect proof of -- a fifth force. The reason scientists continue to search for alternate forces is that the Standard Model fails to explain the existence and behavior of dark matter.
The Hungarian team, led by physicist Attila Krasznahorkay, was looking for dark matter by firing protons at a thin slice of lithium-7. Their experiments produced a different sort of anomaly.
The collision produced beryllium-8 nuclei, which emitted pairs of electrons and positrons as they decayed. According to the Standard Model the number of observable pairs should drop as the angle of the trajectory of the diverging electron and positron gets larger.
Instead, the number of pairs jumped at 140 degrees -- creating a slight hiccup or bump before the pairs again dropped off as the angle continued to increase.
The Hungarian team cited the bump as evidence of a new particle with a unique force.
"We are very confident about our experimental results," Krasznahorkay told Nature.
Researchers at UC-Irvine say the analysis of Krasznahorkay's team is congruous with previous experiments and theoretical results. In their own paper, the UC-Irvine scientists suggest the bump is evidence of a protophobic X boson, which may indeed be carrying a fifth force acting across just the width of the atomic nucleus.
The recent discovery was unexpected, and many particle physicists remain understandably skeptical. The research has yet to be replicated, and finding the same particles again will be quite difficult, but the science world is now paying attention.
"Perhaps we are seeing our first glimpse into physics beyond the visible Universe," said skeptic Jesse Thaler, a theoretical physicist at MIT.