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.

Comments

Re:Face it, the tau neutrino is useless

[gilroy]

Well, I'm not a high energy physicist (although I trained as an astrophysicist), and I always get queasy trying to "predict" spin-offs, but...

Back in the 1960s?, similar questions were raised over the building of SLAC. What possible real use would a two-mile-long linear accelerator be? Of course, once the things were built, it became clear that you could use highly-polarized synchroton radiation for fundamental crystal studies, for materials engineering (about as practical as one can get, in terms of research areas), and biomedical studies. These were not foreseen, but they've become really important.

Not everything is going to be electrons and protons under "normal" conditions forever and ever amen. A lot of the 21st century will be breaking the dumb-monkey mold and designing things because we understand them for once. Current understandings of superconductivity, for example, are intimately tied to the Standard Model and the field theory it enshrines. If the SM is replaced, one can imagine -- and I, for one, would be willing to bet -- that it will impact that and other materials field.

A focus on the "practical" is a guarantee that further progress will end -- in basic knowledge, in human scientific endeavour, and in applied technology. Sagan illustrates this nicely in The Demon-Haunted World. In the 1860s, Queen Victoria (he says) could never, despite her power and the wealth of the British Empire, have commanded the invention of a wireless broadcast technology. Yet a social outcast, pursuing his own interests (Maxwell) laid the foundations for the entire telecommunications revolution that we like to preach about. Directed research would never have produced the same results as serendipity, becuase we would never have asked the right questions.

So this probably will be useful for applications someday, in some way. And I'll just leave out the higher, ennobling ends of science. If I have to discuss them, you probably wouldn't understand them anyway.

Re:The truth is a bit more complicated

[Tau Zero]

Is THAT what Cerenkov radiation is? Does anyone know what Cerenkov radiation itself is? Is it EM, or beta particles, or what?

It's EM, photons around the visible spectrum mostly. Have you ever seen a picture of a "swimming pool" style research reactor, with the core engulfed in an angry blue glow? That's Cerenkov radiation. Gammas from the reaction, decay of fission products and neutron captures by hydrogen scatter off electrons, and the momentum transferred to the electrons leaves them moving through water faster than light. The electron transfers energy to all the little quantum EM fluctuations moving in more or less the same direction (the photonic equivalent of a "sonic boom"), and the electron rapidly slows down to less than the speed of light in water while the quantum fluctuations become real photons. Judging from the spectrum I'd guess that there's a lot of Cerenkov radiation in the ultraviolet, but given the lack of sunburn warnings it must not get very far in water.
--

Re:Face it, the tau neutrino is useless

[sigwinch]

Knowing more about the tau neutrino lets you fix some parameters in the Standard Model that have NO APPLICATION in any other field.

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.

EVERYTHING that any engineer might put into use is going to be made up of ordinary matter: i.e. protons, neutrons, electrons.

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.

[A chemist's] life is based on what happens near ROOM TEMPERATURE where any contributions of neutrino physics are either ZERO or taken into account by the effective fields that he uses

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.

Re:So how do we use these?

[mikpos]

Actually this brings up an interesting point. Would it be at all possible to use neutrinos to slice bread? I'm going on the presumption that not having to sharpen your knife outweighs all possible disadvantages.

Re:"break the Standard Model" duh?!

[CrusadeR]

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).

Oh Canada

[YoJ]

The Canadians have a neutrino detector too. It's in Sudbury. Take a look at:

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

All I want to know is...

[KaiShin]

When's it gonna appear in a Star Trek movie? Captain! We've got to reverse the Tau Neutrino flow through the warp transducers!

Big news!

[styopa]

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.

Re:Big news!

[drinkypoo]

They should never have changed beauty and truth quarks to bottem and top. I think they lose their charm.

Obviously, you're not into bondage.

I wanna be a professor!

[rjamestaylor]

George Tzanakos has truly inspired me to seek my PhD and become a professor. That is, once I saw the picture with this caption: George Tzanakos (Univ. of Athens) and his graduate student Niki Saoulidou.

("His graduate student"? A wee-bit Freudian, don't you think??)

Not only that...

[11223]

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.

Re:Not only that...

[HomeySmurf]

I have a problem with these "mass difference" boundaries on different types of neutrinos. The problem with neutrinos is that they are neutral and very light. That means they don't really interact with matter. They are detected by huge tanks of water. When the occassional neutrino interacts with a water molecule, they use calorimetry to measure its energy and thus deduce its mass. Now if this sounds like a very imprecise measurement method, it is. That is the problem.

The other thing is that they three traditional neutrinos are linked to the three leptons (electron, muon, and tau). A forth neutrino would probably not be part of this triumvirate, and why a tau neutrino was predicted but not measured before. The idea is that is required for the conservation of energy in weak interactions with tau particles. For example, the original (now electron) neutrino was posited to exist for conservation of energy in the decay of a neutron into a proton and electron (the extra energy went into the neutrino).

Actually the standard model links the 3 leptons to the 3 quark family only because that is what is involved in the energy reactions we have observed. When you hear about these 3 pairs, there is nothing restricting there from being an infinite number of heavier "fundamental" particles, but they would be so much heavier than the top quark, that we will never have funding to try to detect them.

One last thing is that there is some stuff about the Higgs scalar boson in this month's Scientific American. This is the scalar field responsible for mass and gravity. It is probably worth reading if you are into this stuff. It is one of the things that CERN is trying to detect. It is interesting that the US based Fermilab is trying to concentrate on tau neutrinos which are available at a much lower energy, and thus we are trying to make up for the lack of a cutting edge accelerator, while CERN forges ahead to make up for there loss in the top quark race.

Re:Not only that...

[the_other_one]

Once the third neutrino was found the Standard Model had to be changed adding a fourth neutrino to allow for continued funding.

So how do we use these?

[dagoalieman]

I still haven't heard of a practical use for the neutrinos other than to give scientists something to do. Is there someway we can use these for a practical purpose or to explain anything???

If there isn't, why are we wasting our money??

Re:So how do we use these?

[alleria]

It is, to a point.

But stuff that doesn't have good commercial or military viability languishes on the back burner for lack of funding, and many eventually get canned. Fact of life.

On the other hand, scientific discoveries always eventually have applictions, and most places are smart enough that way to fund projects even if the applications are still hazy. Which is good.

Re:So how do we use these?

[styopa]

Few small problems (I'm sure mine does too).

First, neutrinos can interact with matter. They happen to be inert and therefore will not go out of their way to but they do have energy, and therefore can effect/interact with matter. People build detectors for neutrinos deep in the earth because it has a better chance of not interacting with anything. Assuming it is massless then only the weak and the strong nuclear forces can effect the neutrino, and considering the distances required for interaction are on such a small scale.

Photons interacts more readly partially because they are the electro-magnetic force particle. It also generally contains more energy and therefore its interactions are more pronounced, IE the transfering of an electron from one energy level to the next.

As for the theory that the "lack" of matter being explained by neutrinos having mass had been dropped last I checked. There are other discussions on where the dark matter is, the machos and the wimps.

Re:So how do we use these?

[Tiro]

Cool, sort of like that underwater modem we heard about a while back. Except neutrinos should, in the long run, [assuming points 1-3 above are taken care of] be a hell of a lot more useful than sound waves.

Imagine... could we send a wave of neutrinos underground from Warsaw to Madrid, [To pick two random points], assuming points 1-3 above are dealt with?

Someone please answer me that. This whole discussion is so damn interesting; too bad I don't have the backround [yet] to understand much of it.

Re:So how do we use these?

[carlos_benj]

I once saw a proposal to research the use of neutrinos for communications with submarines....

....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 about the others, but couldn't you take care of number two by having the sub initiate contact periodically since it would likely be communicating with a fixed position?

Re:So how do we use these?

[Faramir]

Replying to a couple of posts...

1) Excellent points made about the future usefulness of particle physics, and basic research in general. We're not entirely sure what it will explain, but there could be a wealth of new physics come out of neutrino research. For instance, by better understanding neutrinos, we may come to be able to better detect and understand other interactions that are going on all around us. I'm just pulling this out of my ___, but perhaps if we could reliably detect neutrinos we would be able to more quickly and easily detect beta decay--the decay of a neutron into a proton, a highly radioactive process that includes neutrino emission. Many applications to that.

2) I'm on a project called MINOS that is trying to determine neutrino rest mass by detecting neutrino oscillations--changing from one flavor to another, say electron neutrino to tau neutrino. As I understand it, the fourth neutrino may be an intermediate, neutral oscillation stage. Best place to look is in journal articles on neutrino oscillation theory. Dr. Duane Dicus at The University of Texas at Austin is one relevant author.

3) Never thought about supernova detection that way. Good point. Photons interact via the electro-magnetic force with all kinds of matter. But neutrinos do not interact with matter in the normal way. They will occasionally interact with their equivalent lepton (i.e. electron neutrino plus anti-electron yields an electron and anti-electron neutrino). So, while light must bend around planets and stars, etc., to get to us from a supernova, many neutrinos would pass right through the intervening matter, until they hit our detector that is designed specifically to stop and read them.

Hope that helps... Oh, and George Tzanakos is an excellent man and a good physicist, I'll have you know!

Re:So how do we use these?

[Tau Zero]

I thought that the reason neutrino bursts seem to show up prior to the photons from a nova...

There's no "seem" to it. They do.

...was because the fusion process releases neutrinos, and the nova is an accelerated fusion process

Yes and no, but first, neutrinos are produced in a supernova when the protons of the collapsing core have electrons rammed into them, forming neutrons by inverse beta-decay (electron capture) and releasing neutrinos. Smack a neutron hard enough with a neutrino, and you can get an electron and a proton again (assuming the energy state of the nucleus allows this; a free neutron will decay by itself). Light escapes from a star when the overlying gas is no longer dense enough to be opaque. For a neutrino, "opaque" is at roughly the density of a neutron star, and it takes the density of matter falling into a collapsing stellar core to be a serious obstacle to escaping neutrinos. Once the neutrinos have leaked out to the less-dense sections of the collapsing star, they're gone (but before that, they are believed to exert a lot of upward pressure on the infalling matter and actually produce much if not most of the supernova explosion). Light can't get out of the supernova until the shock wave, no longer driven by solar masses of neutrinos, gets to the visible surface of the star. This takes hours, whereas the neutrinos are out within seconds.
--

Re:So how do we use these?

[cetan]

I'm clearly not that clever.

Re:So how do we use these?

[John Jorsett]

The best source of reliable info related to military equipment is Jane's. They publish lots of different reference books on weapons, communication systems, vehicles, etc. Unfortunately, they want actual money for their stuff.

You can also sometimes find information on specific items on the web sites of the military contractors building them. They like to showcase their major projects.

Re:So how do we use these?

[cetan]

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.

Re:So how do we use these?

[John Jorsett]

couldn't you take care of number two by having the sub initiate contact periodically since it would likely be communicating with a fixed position

Subs are generally given patrol areas, and it's up to the captain to decide exactly where they are within it at any given time. They're also given discretion on where/whether/when to come to comms depth, since the first priority is to remain undetected.

There was one project I heard of where the idea was to use a blue-green laser (a color which penetrates water well) from a helicopter so that the submarine didn't have to come near the surface. Don't know what ever happened to that. As far as I know, today the only communications system that works when the sub is at depth is VERDIN. It's so slow (in its initial version it was literally seconds per bit) that it has limited utility. To get maximal depth penetration, they were using frequencies @ 7 Hz, and using the earth/ionosphere as a gigantic cavity resonator. To do this, they needed an enormous groundplane, so they were burying miles and miles of wire in the bedrock in the Great Lakes region of the U.S. The power levels were equally enormous. There were amusing stories published when they were testing it. Seems that fences were being electrified, telephone systems fried, St. Elmo's fire breaking out all over the place, and all manner of electrical havoc being wreaked. People in those regions went so nuts that the Navy ultimately abandoned that version of it. Good thing, cuz the ultimate goal was to wire much of the Northern U.S. with the system.

Re:So how do we use these?

[craw]

The DUMAND Project (underwater neutrino detectors) was initially pitched to the Office of Naval Research over twenty years ago. I believe that the initial funding proposal failed. But why would the US Navy be interested in neutrinos in the first place?

Nuclear reactors generate neutrinos. Neutrino emissions cannot be shielded. Big Ruskie subs with rockets that go boom have nuclear reactors. It would be real nice to be able to detect those subs. As it turns out, the US Navy already had a pretty good system for detecting subs; it's called SOSUS. Unfortunately, SOSUS at that time was a tightly kept secret.

Anyway, maybe in the future somebody will build a practical, relatively small neutrino detector. Excuse me sir, but your carry on bag is emitting neutrinos. Can we take a look inside?

Re:So how do we use these?

[John Jorsett]

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.

Re:So how do we use these?

[mdroid]

One use could be that you can detect supernovas before they are visible (before the electromagentic rays from a supernova comes a neutrino burst (no, they aren't traveling faster than light, but the neutrinos can travel straight through matter when radiation (eg. light) must interact (don't know if this is the right word) with the matter (the matter absorbs the light, one electron "jumps" to a higher energy level, the electron "jumps" back and the radiation travels on (with a slight delay)))
(but this is propably scientiststuff ;-) )

One other thing is that (if neutrinos do have mass) is that they could explain some of the "lack " of matter in the universe (often referred to as Dark Matter) (scientist stuff again)

/Droid

Re:So how do we use these?

[jpgrimes]

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

Really bad humor

[Ravagin]

In related news, the scientists who conducted the study are co-authoring a book on the subject, entitled The Tau of Neutrinos.
-J

Funny Slashed-Dots:

[rjamestaylor]

Slow down cowboy!

Slashdot requires you to wait 1 minute between each submission of /comments.pl in order to allow everyone to have a fair chance to post.

It's been 1 minute since your last submission!

Wait a minute! (I did!) Oh!

How it was done..

[lennon]

The interesting thing about this is how the found the proof for tau neutrino existence: their beam left millions of tracks in 3D medium. What they were looking for is a 1 mm track left by a decaying particle, "a track with a kink" as they call it. Computer controlled cameras were used, and I bet some supercomputers were used to search for this pattern (or maybe just a lot of work studies and interns). If this is not an application for distributed computing, I don't know what is.

A fun quote from the article : "Stanford University physicist Martin Perl, winner of the 1995 Nobel Prize for discovering the tau lepton, the first indicator for a third generation of particles, congratulated the DONUT experimenters."

Re:How it was done..

[drinkypoo]

Mmm, Neutrino Donut.

Re:Face it, the tau neutrino is useless

[cetan]

here here!

This is a really good post and well worthy of quite a few + mod points. I wish I could articulate (and expand) my original post as well as you did.

the slashdot effect on scientists...

[ilkahn]

anyone else as curious as I am as to whether having the slashdot effect on fermilabs network connection caused the world of neutrino science to be slowed down for one day? it makes you wonder... did slashdot just 'cause the next big thing to happen one day later just 'cause no one could use their email or their network? :)

Re:the slashdot effect on scientists...

[styopa]

I have a feeling that fermilabs was uneffected by the slashdot effect. Any scientific data that they need to retrieve from other sources are likely going to be on Internet 2 like they are. They have a seperate network backbone to where they need to go, and massive computers.

Re:the slashdot effect on scientists...

[Tau Zero]

anyone else as curious as I am as to whether having the slashdot effect on fermilabs network connection caused the world of neutrino science to be slowed down for one day?

You wish. The data hoses which get the particle tracks from the detectors to the recorders at Fermilab are

1. dedicated, and
2. enormous.

There are hundreds of coaxes coming off of just the CDF at Fermilab, and that's only one of their experiments. The amount of data they can crunch in a second is probably equivalent to an hour's work for Slashdot. Some of the detectors are crunching data internally because they can't move the un-reduced mass of stuff to a room upstairs; it would take a bundle of cables as fat as the detector, instead of only as fat as your torso.
--

Re:The truth is a bit more complicated

[fiziko]

They don't do the calorimetry on the neutrino itself. They saw the creationg and decay of a tau lepton inside the tank. The sudden presence of a tau lepton cannot be explained by current theories without having a tau neutrino present.

Re:Pre-announcing announcements

[fiziko]

Yeah. On Monday, a colloquium speaker at CERN told us to expect the announcement on Friday. I'd have submitted an article then, but I had to URL to link to...

Re:"break the Standard Model" duh?!

[styopa]

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.

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)

The truth is a bit more complicated

[Tau Zero]

What actually happens is that the neutrino smashes into something and leaves a charged particle moving through the water faster than c/refractive index (the speed of light in the medium), and that makes Cerenkov radiation. It's not quite as direct as you paint it.
--

Underground experiment in the works

[re-geeked]

There are plans to send neutrinos underground from Fermilab to a particle detector in the 1500-foot deep Soudan mine in northern Minnesota. The purpose is detecting decays or oscillations to demonstrate/measure neutrino mass. I don't know the status of this idea.

I also don't know whether that means you can transmit armed forces radio via neutrino :-)

Re:Face it, the tau neutrino is useless

[rve]

Well you are right, tau neutrinos have no practical use. Putting men on the moon or sending probes to mars had no practical use. The Pyramids had no practical use, and neither had the chinese wall.

These achievements serve a different purpose. The cost seems very high, but it's only relatively small compared to what we spend on other things that have no practical use, like hollywood movies, beer, and the starwars project part 1 and 2. Although military spending does have a practical use, the amount the military gets to spend on things they want but don't really need dwarfs the cost of building that hand full of particle accellerators the world has.

So yes, from an engineering point of view, using empirical data is as valuable and often more practical than refining the theory to understand every aspect of a project at the design stage, but finding the theory that unifies all the forces in nature, and finally gives us a full understanding of how the universe works, is a project like going to the moon or building pyramids. It's one of the ways we give meaning to life.

Re:We do?

[fiziko]

We're getting better at physics. It comes from slashing the defense budget and staying friends with our neighbors to the south. We've also got the world's largest cyclotron in B.C., called TRIUMF.

Re:"break the Standard Model" duh?!

[Dirtside]

I though the "Super-Kamiokande" was Nintendo's next-generation game console?

But neutrinos DO have mass!

[dysprosium]

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

This will be interesting to see.

[THOAAG]

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.

"break the Standard Model" duh?!

[efuseekay]

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.

Re:"break the Standard Model" duh?!

[Chris Burke]

Actually, the summary said that it would be the discovery that neutrinos had mass that would break the SM.

I think most everything we think we understand is just an approximation (low energy, macroscopic, etc) of reality. The electric and magnetic forces are just parts of electromagnetic force, which is just a low-energy special case of the electroweak force, etc. Haven't we noticed a pattern yet? Our theories only work for those ranges in which we are capable of looking, and will break when we expand those ranges.

Big deal, I say. If it wasn't constantly being proven wrong (or "not entirely correct" ^_^), science would be boring.

Area Scientist Says Yay

[LNO]

In related news, the collaboration of scientists at the Department of Energy's Fermi National Accelerator Laboratory gave public thanks to Star Trek writers, saying, "Without those pseudoscientific plotlines, we wouldn't have any direction in our research." When asked about future plans, one stated, "I've always been keen on developing a positronic brain, or maybe building a phasing tachyonic pulse emitter."

Comments of "Get a life, you trekkie" and "Move out of your parents' basement" did not receive replies.

That's a dead theory

[efuseekay]

....First off, it will help us decipher exactly how much dark matter is out there It's now generally believed that neutrinos do not, even at the best estimate, have sufficient mass to make up the "dark matter". .... 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 Cosmological Constant is now in vogue as a solution to the "missing mass" problem. ....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. This statement is, of course, totally wrong. The mass density of the universe do not decide whether we wil have a series of BB and BC or not.

Donut detector invented by Homer Simpson?

[hedgehog_uk]

I guess that's what Homer Simpson was working on at the Springfield nuclear plant.

Yellow tigers crouched in jungles in her dark eyes.

DONUT detector heralds new era in tasty food

[techmuse]

My favorite device in the experiment is the DONUT detector. Although they claim to have used this to find Tau neutrinos, the REAL purpose of this detector is to identify and locate tasty toroidal snack and dessert foods for consumption by hungry physicists.

Re: neutrino communications

[jaoswald]

Yeah. great idea. To create neutrinos in "detectable" quantities you need
a source/transmitter. Your choices:

• 1) star
• 2) particle accelerator

neither of which is particularly cheap AND easy to modulate.
a receiver: your choices:

• 1) **huge** tank of cleaning fluid and array of photomultiplier tubes
• 2) or, something like a huge amount of gallium (i.e., a considerable fraction of the world supply) which will be transmuted by neutrinos and can be chemically detected after a number of *months*.

Oh yeah, (1) needs to be under huge amounts of ROCK to avoid detecting all sorts of other garbage. Neither one is going to fit very well into a sub, and the sophisticated chemistry won't fit very well with the submariners.

Not to mention the "practical" details, like, most US subs have nuclear reactors that likely contribute a huge background compared to the neutrino signal.

The main point is that neutrinos DO pass through matter almost like it wasn't there. Unfortunately, most things you use to detect them are made of matter.

funny, but wrong

[Anonymous Coward]

'Tao' is pronounced 'dao' (or 'dow', or whatever). Tau is phonetic.

I'll respond

[2nd Post!]

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!

Pre-announcing announcements

[Chairboy]

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!

Re:Face it, the tau neutrino is useless

[infodragon]

You are forgetting about serindipidity. The pursuit of unknown properties of physics that may never benefit man will most definitely lead to other discoveries that will. The knowledge that man kind gains from this research will probably lead others down different paths to develop things never imagined before. What ever it is they develop may not be directly related to research into the neutrino but it will never have happened unless the research on the neutrino was conducted.

Then the other side of it is the new tools developed for studying the neutrino have most definitely progressed the sensitivity of measurement devices. These new devices, or more precisely, the technology gained from the development of these new devices will lead science and hence man kind into new wonderful directions never dreamed of before.

Just because it doesn't appear to give any results doesn't mean that it won't or already hasn't. The research into the neutrino has already impacted society more than anybody can measure.

Re:Clarification

[styopa]

Basically, neutrinos are believed to be either RH or LH (depending on whether it is a baryon or anti-baryon), but not "mixed".

I thought neutrinos couldn't be LH.

I also must admit that I am somewhat biased, considering I am doing some research with SUSY and the NLC. You are right, massive neutrinos are not the death of the SM, there are other things that are a problem, like the Higgs Boson's mass diverging. Also, with quite a few theorists today believing in Unified Field Theory, a new fudge factor needs to be entered because the Higgs Boson does not unite all of the forces at one energy.

Those Wacky Scientist Guys

[adipocere]

Walking around with their big white hair, sweatervests inside out, forgetting where they live, and, more importantly, wasting our tax dollars.

Damn me for not knowing it offhand, but there's a pretty famous quote about a queen in some country asking a scientist just how he thought all of this electricity stuff was going to be useful. Might have even seen it here.

Anyway, it's not "can we find a use for neutrinos." Neutrinos interact only weakly (a bit of a physics pun, they don't listen to the strong nuclear force, aka colorforce, just gravity and the weak nuclear), and are fairly intractable.

What is potentially useful is the understanding they give us. With them, we might be able to better understand, say, the weak nuclear force involved in beta decay better. If this sounds abtruse, how about the idea of making old nuclear waste radiate down to stable iron atoms and various other smaller, stable nuclei? Waste disposal problem solved.

In the large scheme of things, neutrinos themselves may not be particularly interesting, but specific numbers, like mass, may eventually answer questions like: Will the universe expand forever, or will it be reborn after a Big Crunch? And, what's the field equation that runs the universe?

Just try understanding electricity without magnetism, and you'll see what I mean.

Re: neutrino communications

[John Jorsett]

a receiver: your choices: 1) **huge** tank of cleaning fluid and array of photomultiplier tubes

As I recall, the proposal thought that the vast quantity of water surrounding the sub might be in some way used for detection. Hey, I never said I thought that this would work, just that someone wanted funds to look into it.

Now the proposal to use modulated black holes to communicate via gravity waves, that had some promise ... :-)

Some first (well, second) hand perspective...

[Brand X]

I took my senior particle physics course from one of the physicists working on Super-K. Dr. Learned spent more time going into neutrino oscillation than focusing on the course material, which was fine by me, as I was the only registered student in the class, and quite enjoyed the tap-in-the-fountain course. So here goes...

One of the models that fits the Super-K results (mind you, we're talking huge margins of error... in some data, 2-3 SDs) involves one sterile (non-interacting) neutrino; another involves three sterile neutrinos, at energy (mass) levels significantly larger than their corresponding interacting neutrinos. All of these possibilities are modeled against several sources; Blackbody spectral distribution, solar neutrino density (also mapped wrt time of year and day, etc) known decay densities (which come out of particle physics, which is hardly elegant and superstring theory models, which are hardly verifiable) and cosmic neutrino burst speeds (so far, we haven't had a huge neutrino producing cosmic event occur that caused neutrino detection to spike a measurable time interval after the photon detection... shame, that, and it really forces the upper limit on electron neutrino mass down, which is ugly if you assume those are massless neutrinos... but oscillation models require mass on "heavier" neutrinos, which means... aw, the hell with it... this is why I ended up liking solid state so much.