The international T2K neutrino experiment has found more evidence that neutrino oscillations appear to violate the symmetry between matter and antimatter. While it’s still too early to claim this as a discovery, the research strengthens the hints that had already been seen with the experiment last year.
The preliminary analysis presented at the High Energy Accelerator Research Organization (KEK) in Tsukuba, Japan, revealed the team from the Tokai to Kamioka (T2K) neutrino experiment – a particle physics experiment collaboration between several countries – obtained twice the neutrino detections compared to the previous results.
This new research has a 95 percent confidence level in rejecting the so called charge-parity (CP) symmetry hypothesis that neutrinos and antineutrinos behave in the same way. While 95 might seem good, a discovery is only accepted when researchers have a 99.99994 percent confidence from the data.
"By doubling our neutrino mode data and making analysis improvements, T2K has made the most sensitive search for CP violation in neutrino oscillations yet,” Professor Mark Hartz from the University of Tokyo Kavli Institute for the Physics and Mathematics of the Universe, said in a statement.
“This data shows an intriguing hint of CP violation. To make a definitive measurement, T2K will need to collect additional neutrino mode and antineutrino mode data.”
This new data goes towards supporting other interesting violations of CP, like the discovery of a new pear-shaped atom. Researchers are at looking at these types of violation to explain why there’s more matter than antimatter in the universe. The charge-parity symmetry requires that if we switch every particle for its antiparticle, and mirrored the set-up of the space, physics is expected to behave in the same way. But if it doesn’t then we can justify why the universe is made of matter.
And in the T2K experiment antimatter is not behaving as it should. The experiment has detected 89 electron neutrinos when about 67 were detected with no CP violation, and detected seven electron neutrinos were theories stated nine should have been observed. Neutrinos are tiny and they hardly interact so even such a small number of detection is important. Every neutrino counts.
“As a T2K collaborator, I am excited to continue our long-term program to search for CP violation in neutrino oscillations and make precision neutrino oscillation parameter measurements," Professor Hartz, who presented the new data, added.
The T2K experiment has a curious setup compared to other standard labs. The neutrinos are shot from a research center in Tokai to the Super-Kamiokande neutrino detector 295 kilometers (183 miles) away, hence the name T2K. It will continue to look for potential violations of CP symmetry and maybe soon it will have enough evidence to confirm it.