Neutrinos, Muons and the Standard Model

scorp1us writes: "I can't believe I haven't seen this posted yet. Apparently experiments in particle physics aren't holding to theory. The result: a search for a new form of energy or matter. Read about it in the Post. No wonder witches weigh as much as a duck."

Comments

A "high" powered "particle" beam?

[Anonymous Coward]

Peter Meyers, a professor of physics at Princeton University who was not part of the research team, said the finding is the "sort of crack" that "has been sought for many, many years."

Great. It looks like it's not just the moderators, then.

Deja vu, and not a very good article.

[Christopher Thomas]

This was posted a few days ago, along with links to much better articles:

http://slashdot.org/article.pl?sid=01/11/08/222121 3

What the experiment shows is that the plan-vanilla Standard Model doesn't perfectly match reality. This is a surprise to nobody.

The results give a tantalizing look at one region of this breakdown, but proclaiming "a new form of energy or matter" is a bit premature at this point. What this will actually do is help confirm, refute, or fine-tune a few of the new models that are replacement candidates for the Standard Model.

Not Reviewed Yet

[TheBoquaz]

I found it interesting that these "results" ended up in the media before being accepted by the Journal they are publishing in.

In science, especially physics, there is a tradition of review which has caught many claims such as this before.

It is likely that they have missed some minor force or effect in thier Standard Model calculations, or that we simply need to understand neutrinos better.

Until a Physical Review Journal accepts research, and even sometimes after that, it should not be viewed as anything more than fantasy.

Re:Always wondered...

[Daniel Dvorkin]

All science is based on "educated guesses." It's just that some guesses are much more educated than others, and turn out to fit the facts pretty well. Relativity is one of those very good guesses, along with Newton's laws (and no, Einstein didn't replace Newton, just refined Newtonian physics in a small but significant way), Darwinian evolution, plate tectonics, Boyle's law, etc. ...

But this is the defining characteristic of science: everything, always, is open to question. Hypotheses that are borne out by experiment and observation turn into theories, and those theories which stand the test of time are honored by being called laws, but none of them are "facts" in the sense that they can't be proven wrong. This is the principle of falsifiability, and it is the one thing which sets science apart from religion, philosophy, law, and other areas of human intellectual endeavor which seek to make statements about our world.

So relativity isn't a "hard fact." Neither is gravity. But that gravity, and relativity, and evolution, and plate tectonics, et bloody cetera, will operate the way the theories say they will, is the way to bet unless and until something dramatically better -- and by "better" I mean "backed by lots of reproducible evidence" -- comes along.

/me applauds.

[Forager]

Since neutrinos are so small, most of the time they passed through the nucleus without affecting it. The frequency of collisions told scientists about the electromagnetic forces that affect how neutrinos behave -- the so-called weak forces. The scientists found slightly fewer interactions with one of the weak forces than had been predicted by the Standard Model, physicists' current description of fundamental forces and particles. Since the model is very precise, scientists concluded that the difference was significant. (emphasis mine)

This is what I love about science. Here we have the Standard Model, formed from exhaustively detailed tests over the last 30 years. As the article states, the model is very precise, and slight deviations are significant issues. However, rather than scrap the entire idea, or announce that the tests were probably flawed, or decry the scientists who performed the tests as heathens and radicals, here we see that the community will embrace this new data and reform the model in such a way as to make it work.

This is the beauty of science. If something doesn't work out the way it was supposed to, if a theory doesn't fit with the cold, hard data, the majourity of scientists will go out of their way to fix the theory (not the data). Scientists are always going out of their way to keep each other in check; at any given time one scientist may be checking some prominent theory or another. It keeps them honest, and while the system isn't fool proof, it's damn tight.

Sometimes it's great to be a geek.

~Aaron.

Re:More forms of matter?

[Mr. Slippery]

I thought the guys who won the Nobel Prize for Physics already discovered a new form of matter. Is this more of their findings, or something totally different?

Totally different. The Nobel guys found a new state of matter, the Bose-Einstein condensate.

Does this mean that there could be 2 new forms of matter to bring the total up to 5 forms?

There's already (at least) 5 states of matter: solid, gas, liquid, plasma (gas so hot that it gets ionized - the sun's made out of it), and the recently confirmed Bose-Einstein Condensate (gas so cold that weird quantum things start to happen).

You've also got the degenerate states of matter found in white dwarfs (where the electrons squeeze together), neutron stars (where the electrons smush into the nucleus), and black holes (where...well, it all breaks down there). These don't seem to be counted in the usual enumeration of states of matter, but then they've never been produced on Earth, they're really still theoretical.

What they'd be looking for out of this new discovery is more along the lines of a new fundamental particle or force.

Re:Not that significant

[Zeinfeld]

I wouldn't make any long term plans based on this paper. The "one chance in 400" is misleading -- if you look at the paper, what it's really saying is that their experimental result differed from their theoretical result by three standard deviations (three sigma). On the face of it, this isn't very impressive. The trouble with straightforward statistical analysis in this fasion is that particle physics is hard. Experiments are being done at the limits of detectability, and often in ways that have never been done before.

As a former experimentalist in the field (they gave me the Phd so I couldn't be all that bad) I am not getting excited.

The problem is that the experiments are simply not accurate enough to jump up and down in celebration for such a miniscule deviation.

What I am really suspicious about is that the number of observations is much lower than expected. That can happen because you just missed some particles you should have seen.

You can have a deviation that is 'significant' at twenty or a hundred standard deviations and it can still be the result of experimental error rather than a flaw in the standard model.

Given the way the physicists write their programs I would not be at all surprised if this turns out to be no more than the result of a flaw in PAW or GEANT. A physicist will go off to beg congress for a billion dollars to four experiments on the same accelerator (e.g. LEP) so that each can cross check the results of the other. Then they will all share the same analysis programs even though they are known to be riddled with bugs. And don't start on about the Web, first off the Web code was not built on a twenty year old code base from the dawn of Fortran, second there were multiple versions of the code written from the very start. In 1992 there were 10 browsers and at least 5 Web servers.