Credit: Univeristy of Tokyo
There are diminutive visitors to Earth. We’ve known about them and measured their presence since the 1960s. When the Sudbury Neutrino Observatory (SNO) turned on in May, 1999 the world became acutely aware of tiny particles known as solar neutrinos. The facility gathered data for seven years before shutting down and we’ve heard little in the media about neutrinos since. As we know, mass cannot be either created nor destroyed – only converted – so where did it originate? Exciting results produced by the international T2K neutrino experiment in Japan may be key to resolving this riddle.
To understand neutrinos is to understand their flavors: the electron neutrino teamed by particle interactions with electrons, and two additional marriages with the muon and tau leptons. Through research, science has proved these different types of neutrinos can spontaneously change into each other, a phenomenon called ‘neutrino oscillation’. From this action, two types of oscillations have been documented during the T2K experiment, but a new format has come to light… the introduction of electron neutrinos in a muon neutrino beam. This means neutrinos can fluctuate in every way science can possibly dream of. These new findings point to the fact that oscillations of neutrinos and their anti-particles (called anti-neutrinos) could be different. If they are, this could be an example of what physicists call CP violation. This would be a tidy explanation of why our Universe breaks the laws of physics by having more matter than anti-matter.
Unfortunately, the T2K neutrino experiment was disrupted by this year’s devastating Japan earthquake. But the team was prepared and both they – and the equipment – weathered the catastrophe. Before shutting down, six pristine electron neutrino events were recorded where there should have only been 1.5. With odds of this happening only one in one hundred times, the team felt these findings weren’t conclusive to confirm a new physics discovery and so they listed their results as an “indication”.
Prof Dave Wark of STFC and Imperial College London, who served for four years as the International Co-Spokesperson of the experiment and is head of the UK group, explains, “People sometimes think that scientific discoveries are like light switches that click from ‘off’ to ‘on’, but in reality it goes from ‘maybe’ to ‘probably’ to ‘almost certainly’ as you get more data. Right now we are somewhere between ‘probably’ and ‘almost certainly’.”
Prof Christos Touramanis from Liverpool University is the Project Manager for the UK contributions to T2K: “We have examined the near detectors and turned some of them back on, and everything that we have tried works pretty well. So far it looks like our earthquake engineering was good enough, but we never wanted to see it tested so thoroughly.”
Prof Takashi Kobayashi of the KEK Laboratory in Japan and spokesperson for the T2K experiment, said “It shows the power of our experimental design that with only 2% of our design data we are already the most sensitive experiment in the world for looking for this new type of oscillation.”
And we’re looking forward to their findings!
Provided by Universe Today - Science and Technology
