The different rates of neutrino and anti-neutrino oscillations recorded by an international collaboration of researchers in Japan - including from Kavli IPMU - is an important step in the search for a new source of asymmetry in the laws that govern matter and antimatter.

The Standard Model of particle physics describes the basic building blocks of matter and how they interact. It also makes a point that for every particle created, there is an anti-particle.

However, the Standard Model does not explain why our Universe still exists today, since the matter and anti-matter symmetry implies that matter - including galaxies, stars, and even humans - should have been annihilated by the equal amounts of anti-matter.

This violation of symmetry, called the charge-parity (CP) violation, has been observed experimentally, but not enough to explain the large amount of matter existing in the Universe.

The international T2K (Tokai-to-Kamioka) collaboration is the first experiment in the world that can search for CP violation by studying neutrino and anti-neutrino oscillations. High intensity beams of muon neutrinos (or muon anti-neutrinos) are produced at J-PARC (Japan Proton Accelerator Research Complex) on Japan's east coast, and fired towards the Super-Kamiokande detector 295 km away in Gifu Prefecture.

On the way, the neutrinos and anti-neutrinos spontaneously change 'flavor' from muon neutrinos or anti-neutrinos, to electron neutrinos or anti-neutrinos. A difference in the rates of oscillations in separate neutrino and anti-neutrino beams would be proof of an imbalance between particles and anti-particles, and that there is new physics to be learned beyond the Standard Model.

The first data set by T2K was published in April, and detected 32 electron neutrinos and 4 electron anti-neutrinos.

"While the data sets are still too small to make a conclusive statement, we have seen a weak preference for large CP violation and we are excited to continue to collect data and make a more sensitive search for CP violation," said T2K collaborator and Kavli IPMU Project Assistant Professor Mark Hartz.

Recently, the T2K experiment has finished collecting another set of data that has doubled the amount of data available in the electron neutrino configuration, and its results are expected to be presented later this year. Hartz has said they expect to continue to take data for another 10 years.

"If we are lucky and the CP violation effect is large, we may expect 3 sigma evidence, or about 99.7% confidence level, for CP violation by 2026," he said.

Details of T2K's most recent results using neutrino and anti-neutrino data were published in Physical Review Letters as an Editors Suggestion on April 10.

Research paper

Tweet

Muon magnet's moment has arrived
Chicago IL (SPX) Jun 05, 2017
What do you get when you revive a beautiful 20-year-old physics machine, carefully transport it 3,200 miles over land and sea to its new home, and then use it to probe strange happenings in a magnetic field? Hopefully you get new insights into the elementary particles that make up everything. The Muon g-2 experiment, located at the U.S. Department of Energy's (DOE) Fermi National Accelerat ... read more

Related Links
Kavli Institute for the Physics and Mathematics of the Universe
Understanding Time and Space

Thanks for being here; We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain. With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords. Our news coverage takes time and effort to publish 365 days a year. If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.
SpaceDaily Contributor $5 Billed Once credit card or paypal		SpaceDaily Monthly Supporter $5 Billed Monthly paypal only