An international team of scientists said Friday it has observed a phenomenon that strongly challenges the existing standard on particle physics and raises the prospect of a discovery of a new set of elementary particles.

The team, comprising about 50 research bodies worldwide, including the High Energy Accelerator Research Organization in Tsukuba, Ibaraki Prefecture, announced the findings at an international conference in Beijing based on experiments using large-scale accelerators in Japan and the United States.

The discovery is part of a continuing quest by scientists and researchers to find models or theories to explain certain behaviors that cannot be explained by the existing Standard Model of Particle Physics.

The existing theory describes the strong, weak and electromagnetic fundamental forces as well as fundamental particles that make up all matter.

Almost all experimental tests have agreed with its predictions, but the model is not a unified theory of fundamental interactions because it does not describe gravity.

If further tests confirm the new phenomenon, team members say it could lead to a re-examination of particle physics because a set of undiscovered particles known as supersymmetric particles is believed to be causing this phenomenon.

"The findings strongly point to the existence of new physics that goes beyond the Standard Model," said Hiroaki Aihara, a University of Tokyo professor and corepresentative of the team, referring to the findings, which heightened such a probability to 99.99 percent.