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First Direct Evidence Of Tau Neutrino
leb writes: "An international collaboration of scientists at the Department of Energy's Fermi National Accelerator Laboratory will announce on Friday, July 21, the first direct evidence for the subatomic particle called the tau neutrino, the third kind of neutrino known to particle physicists. This site has extensive coverage of the event with pictures and related material. The new direct evidence for the tau neutrino is far from closing the chapter on neutrino physics. Scientists are eager to learn whether neutrinos have mass, a
result that would put a crack in the Standard Model, leading to major changes in our picture of the evolution of the universe." The site has some great explanatory diagrams to boot.
Their experiment is *not* an academic exercise of adding a few more digits to an existing measurement. It is the conclusive discovery of a particle whose existence was implied by mathematical symmetries. It's easy to say "yeah, we expected it", but consider that conclusive failure to detect the tau neutrino would have been utterly astonishing, and would have turned all of theoretical physics inside out. If the Standard Model is wrong at high energies, it is also wrong at room temperature, and you would suspect the existence of undiscovered interesting (and useful) phenomena at room temperature.
And photons. And whatever it is that causes gravity (which, BTW, is unexplained by the Standard Model). You ignore nuclear engineers, whose work is strongly and directly affected by quarks, gluons, and color charge. Not to mention the people who will be cleaning up after nuke engineers, possibly using particle beam transmuters.
And I'd wager that spacecraft engineers are rather concerned about where cosmic rays come from, what they do when they hit ordinary matter, and how likely they are. When a fully-ionized iron nucleus with the kinetic energy of a rifle bullet shows up, high energy physics suddenly seems rather relevant.
This conveniently ignores the many uses of radioactive compounds (such as the radioactive tracers used for DNA analysis, metabolism studies, and PET scanners). These compounds are not made in billion-dollar government labs or giant reactors -- they are custom transmuted by privately owned particle accelerators in ordinary office buildings. If that's not good enough for you, how about the manufacture of radioactive cobalt for sterilizing food.
Have you ever heard of gamma ray bursts (GRBs)? Do a web search if you haven't. These things can reach halfway across the universe and ionize the Earth's atmostphere as much as the sun normally does. If we were caught in the beam of a nearby GRB, we'd be toast.
Have you heard of the solar neutrino problem? Neutrino measurements show that either the sun is going out, or that we don't understand basic physics very well. Don't know about you, but I consider Sol pretty relevant to my life.
Finally, much political power rests on mastery of nuclear power. Fast breeder reactors create strife, and military might rests in large part on nuclear submarines and aircraft carriers. What do those things have in common? They're all bright neutrino sources. Discovery of a sensitive neutrino detector would give the discovering nation tremendous power. They could monitor the power levels and reaction spectra of the enemy's weapons reactors and thus tell roughly how much plutonium was being produced. And they could track all the world's submarines. A good neutrino detector would change the world as much as ICBMs did. Of course, it is likely impossible, but remember that respectable scientists once pooh-poohed nuclear power the same way.
I'm not saying we'll all put neutrino ovens in the kitchen in five years, but that doesn't mean that the research is worthless and good only for keeping scientists off the streets.
-- ;-)
Kuro5hin.org: where the good times never end.
Because neutrino oscillation (which there is strong evidence for thanks to the efforts of the Super-Kamiokande team) requires that neutrinos have mass; unfortunately, the manner in which they change types may require (mathematically speaking of course) another type of neutrino. Now this clearly will require a modification to the Standard Model, which originally only postulated the existence of 3 neutrinos to match the three lepton types (disregarding anti-particles of course).
:wq
Sudbury Neutrino Observatory
This detector is designed to answer the "solar neutrino problem", namely that we keep detecting half as many neutrinos as we should be from the sun. Where did the other half go? One theory is that neutrinos oscillate between types. I.e. a muon neutrino oscillates into a tau neutrino as it travels to the earth. The new form of neutrino is then not detected because the original detectors only detected muon neutrinos. SNO will be able to detect both types and distinguish between them, so it should be able to convincingly answer the question of the missing neutrinos.
nojw
This is great news for particle physics. Hopefully the discovery of predicted tau neutrino will show Congress that particle physics is still making discoveries, and therefore fund it.
As for the comment on the standard model breaking down, it broke down when Feinman was still alive and doing major work. The introduction of the Higgs Field heralded this breaking.
One problem with the standard model is that it doesn't account for the masses of the particles by itself. A graduate student, Higgs, predicted that there was a particle that emenated a "mass field", this was dubbed the Higgs Field particle. This fixed up many of the complications mathematically, but created its own problems. If one uses the standard model to predict the mass of the Higgs Field particle it diverges (heads towards infinity) which is unphysical. There are theories like supersymmetry that are being introduced to fix these problems with the standard model.
Other interesting things that can occur now that the Tau Neutrino has been discovered more research on figuring out whether or not neutrinos have mass will become easier. The basic premis behind the test is that the group over at Fermilab will send mu-neutrinos, or now tau-neutrinos, down a long tunnel. If the the mu-neutrinos, or tau-neutrinos, deteriorate into electron-neutrinos or change polarization, then we know that they have mass. Knowing whether neutrinos have mass is VERY important to knowing which new model is correct.
Disclamer - Opinion of Person
("His graduate student"? A wee-bit Freudian, don't you think??)
-- @rjamestaylor on Ello
But in a recent ferminews, there was an article about how there may be 4 types of neutrinos - breaking the Standard Model! The article is here, on Fermi's site.
The tau-neutrino is predicted by the standard model but massive neutrinos are not. In fact, the standard model cannot predict, or account for, mass without the Higgs Field Particle, which has not been observed yet. Masses to neutrinos is not part of the basic SM, the different theories are additions to the SM, or in geek speak, modules. There are two discussions one whether neutrinos have masses, there is the massive neutrino theory and the light neutrino theory. Neither have been fully accepted into the SM.
The SM has been broken for quite some time anyway, every sense the introduction of the Higgs Field particle. There have been numerous attempts to remove the SM because of its flaws. The only reason we haven't thrown it out yet is that there is nothing else that everyone can agree on as being a better truth. Whether it be Technicolor, SUSY, mSUGRA, SUSY with mSUGRA, etc...
The whole mass issue has been a problem with the standard model, that and unification theory. First it didn't predict/account for masses. The fudge factor that was introduced, the Higgs Field particle, which eliviate that problem had a diverging predicted mass for itself. Now most people agree that neutrinos have mass, but are they light or massive. Even with the Higgs boson all of the forces do not unite at a given energy, which is another problem.
(begin rant)
The Standard Model is broken, it has been broken, and as it stands it will always be broken. It's time to get a new model. Whoops the government probably won't support the NLC because the amount of money that the US would have to contribute in this multinational effert is equal to 2-3% of the our militaries budget. Now what?
(end rant)
Disclamer - Opinion of Person
Neutrinos have mass. See here
an announcement dating from June '98 to that effect.
and this doesn't break the standard model at all, btw
I hope that the particle does have a decent mass. First off, it will help us decipher exactly how much dark matter is out there. Secondly, it will help us figure out if the universe is either going to expand forever, expand to a point, or eventually contract down upon itself. The more mass these neutrinos have, the more likely it is that the universe is a never ending series of Big Bangs and Big Crunches.
The tau neutrino is PREDICTED by the SM! So how it's detection break it?
Also, massive neutrinos are easily accomadated by the SM too, so that's a non-issue.
Having said that, the SM is now widely believed to be INCOMPLETE, i.e. it is just a low energy approximation of some thing more complete. (Yes, we only have accelerators at "low" energy, even the dead Supercollider is "low" energy..)
/. should really have a resident science nut.
Mode (3) smart-aleck mode. Press * to return to main menu.
Comments of "Get a life, you trekkie" and "Move out of your parents' basement" did not receive replies.
Why is it that 2 seconds after a scientific discovery is made that people think it should be used to slice bread or fix the worlds problems?
There are no direct practical applications from the tau neutrino find. This is not to say that there won't be in the near or even the distant future.
This is about understanding how the universe works. Maybe it's to abstract for people to grasp, but to me it's a nobel pursuit.
In Soviet Russia...michael would be rotting in Siberia!
You aren't an AC, so I'll give you credit beyond just a troll post.
Basic scientific research like this gives us rewards we cannot measure or calculate. It's premise is that we are studying the unknown, so the rewards are just as unknown.
In a similar vein, look at Newton, playing with light, over 200 years ago. How useful was his research into photons, spectra, etc. But look today, at our lasers, our CD players, our gas spectrometers, our fiber optics, etc.
The problem is that we have to do research today for our advances 200 years from now; or farther! Imagine the ridicule chemists of 400 years past had to face, from people who didn't understand the worth of their research? No fault to the people, because they cannot obviously imagine titanium alloys, ceramic superconductors, high energy density batteries, etc. Likewise, you can't be faulted for not envisioning what research of today will give us in the future. No one knows!
Bye!
GPL Deconstructed
I like the new trend towards announcements announcing upcoming announcements. The same thing happened with the Martian water thing and a few other recent stories.
I'd like to pre-emptively announce the announcement of an annoucement tomorrow announcing a new product!
I once saw a proposal to research the use of neutrinos for communications with submarines, which are notoriously difficult to communicate with (sub drivers really hate having to get near the surface to pick up comms). Since neutrinos pass through matter like it's not there, the idea was to aim a neutrino beam through the earth, pointing it directly at the sub, and passing shore-ship data to the sub. Some of the (perhaps insurmountable) obstacles were:
1) Modulating a neutrino beam.
2) Figuring out where the sub is in order to point the beam at it.
3) Detecting the beam (it passes thru matter like empty space, recall).
Don't know if anything ever came of this. Jane's certainly doesn't have the Neutrino Beam Submarine Communications System listed yet.
How is finding out how the universe works wasting our money?
...).
As with most of science no one ever knows how it will ever be useful. But without particle physics you sure wouldn't be using a computer (can you say monitor, cpu, cd rom,
I would guess practical uses for the neutrino will generally be secondary. Neutrinos are produced in a lot of high energy reactions (can you say in the sun) as by products. Those reactions certainly have practical applications.
I'm still hoping for a neutrino "telescope" (that sees more than the sun & SN1997A).
Also I would point out that super Kamiokande has data that, although still somewhat controversial, looks to be proof of neutrino mass.
john