Category: "particle physics"

Has a new force been discovered?

Link: http://www.nature.com/news/has-a-hungarian-physics-lab-found-a-fifth-force-of-nature-1.19957

In physics, we know there are four forces so far. They are gravitational, electromagnetic, weak and strong forces. These are believed to be fundamental forces in nature.

A fascinating experimental result from a Hungarian physics lab was reported on January 2016, which might be the evidence of the fifth force. The new particle which mediates the force is a boson 34 times heavier than the electron (17 MeV).

Theoretical physicists in the US checked their data whether they might have inconsistency with the other experimental results. However, it was found that the data by the physics lab in Hungary did not conflict with other results.

In their experiment, protons are bombarded the thin targets of lithium-7 to create unstable beryllium-8 nuclei, and then they decayed to generate pairs of electrons and positrons. When the angle of the collision becomes larger, the number of pairs should be decreased according to the standard model, but they found that the number of pairs jumps up when the angle becomes 140 degrees.

This result implies there is a very short-range force, and it does not seem to correspond to any of past predicted particles.

We can also point out that this phenomenon may not strictly be conjectured with the standard model. The theoretical aspect could be extended later if the experimentalists obtained further facts.