Disappearance of Antimatter After Big Bang

One of the most fascinating questions in science is why the universe is primarily composed of matter instead of an equal amount of matter and antimatter. The field of neutrino physics may now have a possible answer.

 

The phenomenon of neutrino oscillations has been intensively investigated for many years. Neutrino oscillations refer to the reciprocal transformation of different types of neutrinos into each other. Neutrinos are electrically neutral elementary particles, which only possess a minuscule probability of interaction and thus are very difficult to recognize and measure.

A leading measurement of neutrino oscillations is a result of the T2K experiment. It sends an intense beam of neutrinos from JPARC, the Japan Proton Accelerator Research Complex, on the east cost of Japan a distance of over 300 kilometers to Super Kamokande, a 50,000 ton detector underground. Researchers have now succeeded in measuring a difference between the oscillations of neutrinos and antineutrinos. This difference is called the CP violation in elementary particle physics. “It is so strong, that the opposite, that is the CP preservation, only possesses a statistical probability of five percent.” The new findings could offer an explanation for the disappearance of antimatter after the big bang,” explains Dr. Stefan Roth from the RWTH Chair of Experimental Physics, who has significantly contributed to the experiment together with his working group.

The T2K experiment is primarily funded by the Japanese Ministry of Culture, Sports, Science, and Technology and is jointly operated by the High Energy Accelerator Research Organization, KEK, and the Institute for Cosmic Ray Research, ICRR, at the University of Tokyo. An international team of over 450 scientists at 62 institutions in eleven countries also works on the experiment. The group of researchers at RWTH is funded by the German Research Foundation.

Source: Press and Public Relations