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Muon Neutrino To Electron Neutrino Oscillation Conclusively Shown
New submitter Chris Greenley writes "The T2K long baseline neutrino experiment in Japan has just announced conclusive evidence for electron to muon neutrino oscillation at the 7.5 sigma level. (The level needed for discovery is 5 sigma.) This experiment generates a focused beam of electron neutrinos using an accelerator in the J-PARC facility north of Tokyo which is aimed at the massive Super-Kamiokande detector 295 km (185 miles) away, near the west coast of Japan. 'This T2K observation is the first of its kind in that an explicit appearance of a unique flavor of neutrino at a detection point is unequivocally observed from a different flavor of neutrino at its production point.' This result clears the way for CP-violation neutrino studies which could show that 'regular' neutrinos act differently than their antimatter counterparts, a phenomenon that so far has only been observed in quarks. If neutrino CP-violation is found, it could explain why there is such a large predominance of matter over antimatter in the universe."
It's only obvious in SU(5). The currently en-vogue SU(2)+SU(3) lie groups only imply it. But you knew that right?
I haven't told them about the other transition they haven't noticed.
I should use this sig to advertise my book ISBN-13 : 978-1501515132.
Anti-matter rules!
They detected 28 electron neutrino interactions, where they would have expected 5 such events without the oscillation in question. This helps underscore how incredibly hard is it to get neutrinos to show up with anything: even when one is manufacturing millions of them, one is lucky to get a tiny set to then show up in your detector. This is connected to how most neutrino detectors are basically large vats of water or some other liquid, because the most we can generally hope for is that if we put enough mass in the way, some neutrinos will by sheer chance run into things.
This is also relevant to what we expect for stellar neutrino observation. Understanding neutrino oscillation gets us a better idea of what sort of neutrino ratios to expect (as a function of energy levels) in other circumstances. Right now, we can observe a lot of natural neutrinos from the sun. But the only neutrinos we've observed from an identified extra solar location, the 1987A http://en.wikipedia.org/wiki/SN_1987A, which was a very close supernova (so close it could be seen with the naked eye). In fact, in that case, the neutrinos arrived before we saw the light. That's not at all connected to the erroneous claim from a few years ago that neutrinos were going faster than light speed. What is happening here is that most of the light in a supernova is formed in the core, and the core of a star is very dense. So it takes a long time for the light to reach the surface of the star. But from the standpoint of neutrinos even very dense star isn't that much of an issue so they can get to the surface much faster. It is possible that this sort of work will give us better understanding both such neutrinos and what to expect when we do observe them from other close supernova.
Neutrinos are still a major area where there's a lot we don't understand, and this research is going to possibly have major implications for our understanding of these elusive particles.
Unfortunate timing considering what thread your comment follows. Although more unfortunate that you added to the mess by thinking your complaints about Slashdot were more important or interesting than the rather nerdy story. So, you're a contributing part of the very problem you complain about.
It would have been easy enough to just link say to the Wikipedia article on neutrino oscillation which discusses other examples of experimental measurements of neutrino oscillations. You could have been more technical and point to how this contributes, along with other experiments, to measuring components of the neutrino mixing matrix which may be useful for post-Standard Model theories. Or you could have just been both bitter and on-topic and complain that the title is backwards, that this was electron neutrino to muon neutrino oscillations, not the other way around as has been previously observed to some degree in atmospheric studies.
From the experiments I've seen neutrinos travel at the speed of light, which was found and reported with great relish by physicists wishing to undermine the faster than speed of light experiments from a few years ago.
The problem with this is that while it solves one issue, it opens up another, because only objects without mass are supposed to be able to travel at the speed of light such as photons, but neutrinos have been found to change "flavors" or types. And for them to do so requires that they have mass yet they're able to travel at the speed of light. Which is supposed to be impossible.
Clearly something odd is going on. Any physicists care to comment?
Sorry about that. I edited the title a couple times and apparently didn't notice the resulting mix up. At least I did state it correctly in the body.
Doesn't the problem of the muon sticking to the resulting helium nucleus too often pose a more important problem for muon catalyzed fusion than the muon life-time? Would the impossible increase in muon life-time suggested here help muon-catalyzed fusion at all?
I was a little scared to click that link. This is the Intertubes, after all.
Yet it's got that one line that explains everything so nicely "or, as the analogy goes, some reactions did not occur as often as their mirror image."
Err.. it's right in the title, not in the body, whatever... Freaking words...
"If neutrino CP-violation is found, it could explain why there is such a large predominance of matter over antimatter in the universe."
But it probably won't.
Don't be apathetic. Procrastinate!