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Low-Energy Neutrinos Detected In Real Time
Roland Piquepaille sends us word of first results from the Borexino detector in Italy, where an international team of more than 100 researchers has detected low-energy solar neutrinos for the first time. These results confirm recent "theories about the nature of neutrinos and the inner workings of the sun and other stars." In particular, it's now almost certain that neutrinos oscillate among three types, namely electron, muon, and tau neutrinos. The Borexino detector lies almost a mile underground near L'Aquila, Italy, and it sets new standards in the purity of the materials used in its construction.
* Neutrino :)
* History of the neutrinos [from our perspective, mind you]
* The Ultimate Neutrino Page
etc. I should go call up my particle physicist body to post up some comments.
For those interested, the paper itself can be found at http://arxiv.org/abs/0708.2251v1. The team is detecting neutrinos from Be 7 at the rate of 47 per day.
Neutrinos - the cornerstone of *any* nutritious breakfast! (Man, this cereal goes *right* through me!)
Homer: Mmmmm... elementary particles!
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Neutrino physics [Evgeny Khakimovich Akhmedov] [PDF]:
BTW, particle physics has an awesome WWW presence.
Borexino is really an amazing detector, but has a complex history. The experiment is located at an impressive place called the Gran Sasso National Laboratory (LNGS) in Italy. Technically, it is one of the deepest labs in the world as measured by overburdon -- i.e. it has about a kilometer of rock in every direction to shield cosmic rays-- but is actually located high up in the mountains. Interestingly, it is almost directly under where Mussolini was held prisoner and subsequently rescued by German commandos at Campo Imperatore in 1943. It is also near where the movie Ladyhawke was filmed. Anyway, back in 2002 there was a chemical accident when some of the liquid scintillator material (highly toxic) got into the local ground water. The leak was an honest mistake and was actually rather minor as chemical spills go, but it caused a public relations debacle which tangled up the lab and, in particular, Borexino, in a long bureaucratic nightmare. I'm happy to see they are now back in the game producing cutting-edge results.
i\hbar\dot{\psi}=\hat{H}\psi
Well, I guess if you're dogmatic about a subject, you should expect to blow your whole leg off someday....
:^) Good story, Roland!
This is the first story of Roland's that, in my opinion: 1.) Isn't blog whoring (no link back to ZDnet blog, although his home page _is_ pri - midi); and 2.) Is a story of real scientific interest; and 3.) Isn't terribly mis-represented in his summary. So even _I_ won't tag this story.... Isn't that ironic? Don't 'cha think?
It surprises me how a scientific blogger could get the minor, or sometimes major, technical details of the story he posts about wrong, but at times Roland will. But not this time
sigfault (core dumped)
People often suggest on /. that progress on the Internet is driven by the needs of pornographers. But it would be interesting to know how much progress in networking and databases is actually driven by the (huge) data recording and analysis needs of particle physicists. My own interest in operating systems,networks and databases was started by the need to log large amounts of data very fast from lightning strike simulation experiments.
Pining for the fjords
Last time I have heard something about the Neutrinos, there was an unresolved problem: Neutrinos do not have mass, therefore travel at the speed of light. But since they travel at the speed of light they have no sense of time, and therefore it should not be possible for them to change their state as they are practically frozen in time. This and earlier experiments confirm that despite that they change state. Are there already theories why this is possible?
Open Source Alternatives
Not so fast! Try taking a drink from the firehose on this one. You'll see that while the main link is still there, he DID include a link back to ZDnet that got edited out!
You have correctly stated the problem, and the solution is that they must have some mass. There are several experiments underway to measure what their masses are. They are very tiny, probably sub-eV (for reference, the electron has mass of 511,000 eV. and the proton has mass 938,000,000 eV).
Indeed, the presumed oscillations imply that the mass of the neutrino is small, but not zero. See, for example http://focus.aps.org/story/v2/st10 for a good discussion. Getting a good experimental measure of the mass of a particle that interacts so weakly with detectors has been a very long running challenge in experimental physics.
Well then, my compliments to kdawson for showing the way and doing some actual editing.
I'm going to wax somewhat sci-fi here and imagine that detection in real-time of neutrinos might have potential application in regards to communication tech.
In my view I see the ability to detect neutrinos as the first step towards a truly peerless communication system. Imagine that instead of radio waves one were to use neutrino emissions for communication. There would be no (or very little) interference (pass straight through any material) and subsequently the latency of communication from any point on the globe would be decided by the diameter not the circumference of the com point's positions on the earth - meaning that communication delays would be greatly reduced.
Imagine if any communications device could simply connect directly to any other device on the planet at low-latency with high-signal strength - wouldn't that be neat!
Read my Very Short "Stories"
Thank God, we will finally be able to track the Romulans when they are cloaked.
Is buying a Harley Davidson as your first motorcycle since you were 16 at age 49 a midlife crisis issue?
I'm not a physicist but I find such oscillatory behavior fascinating. The first person (as far as I'm aware) to really push geometric relationships of a space as a means to explain its dynamics was Clifford. Einstein went a step further and provided a brillant and comprehensive explanation of the gravity/time/mass/energy relationships as the geometric nature of the space time continuum (correct spelling). Since there are still some really strange anomolies in physics (wave/particle duality for one), its interesting to see strange spatial characteristics manifested by the behavior of a particle/wave (neutrino) moving in a straight line.
prepare the survey weasels.
Neutrinos do not have mass.... therefore it should not be possible for them to change their state
Actually, that's the whole thing... these experiments which show that neutrino flavor oscillates are evidence that neutrinos DO have mass (and also, don't travel at the speed of light).
But the fact that a particle travels at the speed of light doesn't necessarily mean it can't change state. It's true, a photon would not be able to measure the passage of time, but stationary observers like us can measure the passage of time as a photon travels at a finite velocity through the lab. E.g., photons CAN change state (and they are massless).
The reason that neutrino oscillations prove that neutrinos have mass is a little more subtle. We already knew there are three "flavor" neutrino states (electron, muon, tau), which we thought were fixed. But if a neutrino oscillates between these, that requires that a neutrino is actually a linear combination of these three states, and hence there must exist a separate basis of neutrino states which ARE fixed. The only way to do that is if these separate three states are mass states, which must be fixed because of conservation of energy. So, a neutrino is created in the sun with a definite mass state and possibly definite flavor state, but as it travels the mass cannot change, and so the flavor must oscillate. A similar relation between mass and flavor exists for the quarks.
Well then, my compliments to kdawson for showing the way and doing some actual editing.
Today's weather forcast calls for airborne swine throughout the country, and a blizzard localized to Hell.
In other news, CERN scientists stated that they would have detected 90% more neutrinos, except some jackass was playing an MP3 on the data collecting computer, which happened to be running Vista.
Obviously, photons move at the speed of light (by definition). But if they too have 'immeasurably small', not 'zero' mass, that has some rather interesting implications for physics, does it not? [Disclaimer: IAAP, although I don't work in this area.]
Just to clarify, when you talk about photons having mass, you mean nonzero rest mass. Photons already behave in many ways as though they have mass because they have energy.
I think the short answer is: if photons had mass, even small mass, then EM radiation would be dispersive in a vacuum, i.e., different wavelengths would travel at different speeds. I don't think this has been observed. A recent article did report something along those lines, but I didn't see any mention of nonzero-rest-mass photons as an explanation. Rather, they're interpreting the results as a possible verification of one of the predictions of string theory: that high-energy photons induce spacetime lensing that slows them down ever-so-slightly compared to their low-energy counterparts. Hey, who knows -- maybe someone could come up with a nonzero-mass photon theory to explain the results. Or maybe the string theorists are doing that already. I don't know -- like I said, I don't work in this area. Has anyone looked for similar alternative states in photons? See above.