Neutrino Mass Confirmed 318
biohack writes "BBC News reports that results from the MINOS experiment have confirmed that neutrinos have mass. To look for neutrino oscillations, scientists created muon neutrinos in a particle accelerator at the Fermi National Accelerator Laboratory (Fermilab). After passing through a particle detector at Fermilab, a high intensity beam of neutrinos travelled to another particle detector 724km (450 miles) away in a disused mine in Soudan, US. The set up established that fewer particles were being detected at the Soudan site than had been sent from Fermilab, which confirmed that some neutrinos changed their flavor on the way - an effect called neutrino flavor oscillation, which requires them to have mass. 'To put it simply, if they are heavy, it means that there is a lot more mass in the Universe than we thought there was,' said Professor Jenny Thomas from University College London."
bragging time (Score:5, Interesting)
Re:bragging time (Score:2, Informative)
Re:bragging time (Score:2)
Re:bragging time (Score:3, Informative)
Re:bragging time (Score:2)
Great tunes to listen to if you're in an 'altered state'.....especially this one.
If you've never heard of them...give them a try....1st 2 albums are very interesting....
Re:bragging time (Score:2)
They only expected to see one or two neutrinos hit the targets per day, out of billions of particles being shot.
Re:bragging time (Score:3, Interesting)
We created a piece of educational software that I believe is currently in use at the University of Minnesota in their physics class to explain Neutrino Oscillation. Very cool to find out that our project finally saw this kind of resolution, not just for the cool fac
Re:bragging time (Score:2)
Not that there's anything wrong with that.
Re:bragging time (Score:2)
Yeah, the universe ran out of vanilla, so it's substituting a rich, creamy chocolate. Unfortunately, since neutrinos rarely interact with matter, of which women are made, this will little positive impact upon your life.
Re:bragging time (Score:5, Funny)
But the staunch advocates of vanilla aren't at all mute. They've been quite vocal in support of their flavour of choice and have even proposed creating a new sub-flavour, the electric vanilla. Unfortunately for them, however, due to the long legacy of having only vanilla, people have been taught to expect vanilla to be boring. Therefore, the electric vanilla is expected to flop.
Temporarily relieving the boring-vanilla problem, however, someone long ago discovered vanilla in red, green, and blue colours (as well as in cyan, magenta, and yellow, but those are really just the opposite of the other colours). One would hope that the new chocolate flavour would also come in similar colours and--thus far--this seems to be the case.
My humblest apologies for this post; I've been learning particle physics by grading homework in it, and I suspect it's driven me quite mad.
Soudan, US (Score:3, Informative)
http://www.dnr.state.mn.us/state_parks/soudan_und
Re:Soudan, US (Score:2, Offtopic)
That kind of sloppiness is rare for the BBC, but typical for US media. It's probably because so many USians don't know or care about world geography. It would sound weird/inaccurate to hear news about "San Francisco, USA" without mentioning California. But this is exactly how it sounds when US news mention a city in another country and ignore the state/province/region/department where it's located. Here's a good example of a double-whammy courtesy of CNN:
http://www.cnn.com/2006/POLITICS/03/30/bush.ca [cnn.com]
Re:Soudan, US (Score:3, Informative)
"That kind of sloppiness is rare for the BBC"
The US is the country where 100 years is a long time. The UK is where 100 miles is a long distance. Even the British can be guilty of the ol' "Oh, you're from the US? Do you know $PERSON from $SIX_STATES_AWAY?"
The only countries bigger than the US are Russia and Canada, and I don't believe either has anywhere near the number
Re:Soudan, US (Score:2)
Re:Soudan, US (Score:5, Informative)
While this is true, it's somewhat misleading, especially to those will limited knowledge of U.S. history or government. Even many Americans don't understand the difference between as state and a province.
State governments in the U.S. function approximately equally to provincial governments in countries that are not federations. Most of them were not originally independant countries, but were instead provinces and territories that were sponsored into statehood.
A significant fraction of the United States were indeed independant countries at one point. ALL U.S. states have significantly more rights than any given province. Each has its own constitution and government, and, contrary to popular opinion, the states elect the President and Senators. The U.S. president is *not* elected by a popular vote. (Although there have been calls to change this.) A few, most notably Texas, still claim the right to secede from the Union, although no state has really had this right since the end of the American Civil War in the late 1800s.
The U.S. constitution sets up the states as individual entities, unlike provinces. They can each impose their own taxes and own laws. In fact, this is one of the major contentions in our government to this day. States can theoretically impose any law that the constitution doesn't reserve for the Federal government. This causes a lot of conflict and consternation since States are also required to respect contracts formed in other states, frequently under a different set of laws and regulations.
The conflict over gay marriage contracts is one of the more recent flaps this has caused.
States can also each maintain their own militias. Many states have 'State Troopers', who usually do the same kind of jobs as normal policemen, albeit with greatly expanded jurisdiction. A few states have 'State Guards', although they usually don't server a military purpose. They usually come to the fore during natural disasters and the like.
While the U.S. is an extremely tight federation-- the word 'Union' is very accurate-- it is still a federation. Each state is indeed its own nation.
Re:Soudan, US (Score:2)
Very true. However, only one was an independant kingdom.
Re:Soudan, US (Score:2)
Re:Soudan, US (Score:2)
After all, some like to call themselves by the name "commonwealth".
Re:Soudan, US (Score:2)
Re:Soudan, US (Score:3, Insightful)
And Canada is a confederation and our Head of State is Queen Elizabeth II. There's also no such thing as a Prime Minister according to our constitution.
There's a big difference between official status and what's reality. If states can't secede from a "Union" then they aren't soveriegn nations then are they? You may say they technically are, but the day tot da reality is that right now they aren't.
If France just up and said it wanted out
Re:Soudan, US (Score:3, Insightful)
Re:Soudan, US (Score:2)
I don't think it's sloppy. That's not like anybody really cares. When you read news from Germany, they usually don't tell you whether it is Saxony or Bavaria or whatnot.
Re:Soudan, US (Score:3, Insightful)
Come on. If you're discussing a specific event in a specific location they are going to list the location. Location-based new reporting is hardly uniquely American. Besides, if nobody cares why even list the location at all? Just say "some guys figured out some physics thing in this test someplace".
State names can be important when there is a good chance that there may be 3-5 (or more) states containin
Re:Soudan, US (Score:5, Insightful)
Why? They don't care anymore than we (Americans) care that Tijuana, Mexico is more appropriately, "Tijuana, BC, Mexico".
To us, the state is important, but to the British, it's really not that pertinent. The point is that the detector is in the US, not what particular state it's in.
Given how awful most Americans are at geography, your complaint comes off trite and arrogant, sort of like you require people to call you by your full name and title, yet you don't really care whether you get anyone else's name right at all.
*shakes head* (Score:5, Funny)
Re:*shakes head* (Score:4, Funny)
Re:*shakes head* (Score:2)
Absolutely! This is the kind of stuff that made me go into physics in college. I've been waiting for some resolution of the neutrino mass issue for the last 20 years or so. This is the cool stuff! w00t!
Re:*shakes head* (Score:2)
Re:*shakes head* (Score:3, Interesting)
Then you read more and you get,"Of course, most of them travel right through our detectors as well, but once in a blue moon one of them will interact - about one or so per day."
I suppose I am being pedantic, but can anybody explain to me why I should believe their explanation that their not turning up
Re:*shakes head* (Score:5, Informative)
They don't yet have enough data to rule out some alternative explanations. At this point, though, neutrino oscillation (and mass) would really be the simplest, least "out there" explanation. These experimenters would like nothing more than to find that even the oscillation theories don't explain the data. That would open a whole new field of inquiry and possibly lead to Nobel Prizes.
If you're techincally inclined, read about the Minos results [fnal.gov] straight from the horses' mouths.
The seminar talks go into a fair bit of detail about their data analysis, which included "blind analysis." In other words, they kept a significant (and unknown until the end) fraction of their data secret from those doing the analysis. Using the other fraction, they went through their testing procedures -- figuring out how to detect false events, how to deal with various , etc -- using a limited piece of the data. Once they were confident that they had done everything correctly, they opened the whole data set and ran their procedure without changing it.
This protected them from tainting their data by, e.g., throwing out data points that didn't match expectations. That is a common problem, even among good scientists. It's very easy to subconsciously make decisions that bias your results toward the expected answer.
Anyway, I am a physicist, and I think you should believe these guys. Everything I've seen indicates they've done a good, careful job with the experiment.
Re:*shakes head* (Score:2)
Already Known (Score:3, Insightful)
Would slashdot also be interested in posting my own confirmations that light has a finite speed?
Re:Already Known (Score:5, Informative)
... as claimed in 1998 Scientific American article [hawaii.edu]
Re:Already Known (Score:4, Insightful)
Re:Already Known (Score:4, Interesting)
And once before by the K2K accelerator experiment, which was (like MINOS) a controlled, make-your-own-neutrinos, measured-before-and-after sort of experiment. Although one might argue since that used SK as a far detector that it might not be as independant a confirmation as you might like.
The MINOS result is nice because in the first 6 months of a multi-year run, we already have the precision of the K2K results, and that all the experiments point to a similar number. Which makes us feel good that after a few more years work we'll have accomplished the goal of measuring these oscillations way more precisely than ever before, and will have a shot at uncovering more subtle things going on with the neutrinos.
But, that doesn't make good headlines, so you won't read that take on things in the popular press. Same reason as we get a rash of "black holes finally discovered" articles every six months when someone presents some new black hole observations at an AAS meeting.
Fox News had a fun headline though, something like "Feds lose neutrinos, gain knowledge".
PS - note that I'm on both Super-K and MINOS, in fact I created my slashdot account in 1998 to respond to comments about that first SK result. It's pretty neat that doing the experiment a completely different way still shows the same thing happening - so Mother Nature must be up to something real here.
PPS - if you're up in Northern MN for some reason (likely canoeing or fishing) do stop by the Soudan Underground State Park on your way to Ely to take a tour of our lab (and the historic mine). Add a proper geeky component to your otherwise dangerously outdoorsy vacation.
Re:Already Known (Score:4, Insightful)
Re:Already Known (Score:3, Interesting)
Super-Kamiokande showed that neutrinos have mass if our models about solar neutrino production are correct. (There was a slight day/night shift observed too, but that's statistically weaker). SNO-ball provided strong supporting evidence too, by which point pretty much everyone agreed neutrino mass was right theory, but there's still the question of exactly what the solar neutrino flux is made up of.
MINOS s
Re:Already Known (Score:4, Insightful)
Neutrino Mass Confirmed
I know plenty of people who work on Super-K and I'm sure they're as glad as anyone their work has been found accurate. The fact that it took almost a decade to confirm this shows how amazing that first measurement is.
Re:Already Known (Score:3, Interesting)
By relativity, the velocity of light in all reference frames is equal/constant. Therefore, if you were in light's reference frame, then light would be moving past you at c. However, you are in light's reference frame, so you are moving with the light and the light is not moving past you. Contradiction.
Of course, I'm not an actual physicist, so take this with a grain of salt.
April Fools! (Score:2, Funny)
Creighton Mine (Score:3, Informative)
SNO Detector [queensu.ca].
This is new? (Score:2, Informative)
Re:This is new? (Score:2)
Re:This is new? (Score:5, Informative)
The experiment was similar and involved muon neutrinos changing flavors to electron neutrinos in a large particle accelerator.
No, it wasn't an accelerator, and the experiment wasn't similar. [wikipedia.org]
The real question is how many eV are the combined masses of the three flavors? The answer to that question portends much for the state of the universe.
No, not really. Not unless the mass of the electron's neutrino is surprisingly large compared to the mass differences among the different types of neutrinos.
In other news today (Score:3, Funny)
You're making that UP! (Score:2)
TEACH THE CONTROVERSY!!! (Score:2)
"Some people say the universe is governed by universal laws. Others say it is but a joke of the Elder Gods [hello-cthulhu.com].
"I think that part of education is to expose people to different schools of thought." someone said. [sfgate.com] "You're asking me whether or not people ought to be exposed to different ideas, the answer is yes."
significance (Score:2)
Re:It depends. (Score:3, Informative)
Um, no, you're just completely wrong here.
Neutrinos are also very important in understanding the mechanics of radioactive decay. Remember, the entire premise from which neutrinos came from was that decay needed a massless particle that could carry with it rotational momentum. Since neutrinos have M amo
Re:It depends. (Score:2)
Re:It depends. (Score:2)
That is what I have asked myself many times.
Once a post has acquired a few 'Informative' moderations by moderators who don't know the subject themselves, it is very difficult to get it modded down.
After all, 'Troll' or 'Flamebait' will not describe the post properly, and 'Overrated' will only remove one moderation point, and not be visible otherwise.
Meanwhile, the post will remain highly ranked, and thus be very visible.
So, I think the only solution will
Re:significance (Score:2)
Hmm...actually what the WP article says right now (could be different from what it said when you read it) is:
A much more stringent constraint comes from a careful analysis of cosmol
If they are heavy they have more mass? (Score:2)
I have something kinda off topic but its "heavy" as well. Ever seen a pepsi with a wire in it?
Thats right! A stainless steel wire in an old unopened pepsi. Can we find out how that happened? If you want to see it here it is.. http://www.regardingspace.com.wireinpepsi.jpg/ [wireinpepsi.jpg] Happy April 1. The image is legit though.
Re:If they are heavy they have more mass? (Score:2)
http://www.regardingspace.com/wireinpepsi.jpg [regardingspace.com]
Sorry about that.
Dark Matter (Score:4, Interesting)
Re:Dark Matter (Score:5, Informative)
http://en.wikipedia.org/wiki/Hot_dark_matter [wikipedia.org]
Re:Dark Matter (Score:3, Interesting)
Re:Dark Matter (Score:3, Informative)
Re:Dark Matter (Score:2)
That's not nice! (Score:2)
They'll decay in no time...
Re:That's not nice! (Score:2)
Meet the new boss (Score:4, Interesting)
Re:Meet the new boss (Score:2)
Implications regarding the Standard Model? (Score:4, Informative)
We'll have to wait and see, but for anyone who would like more information, Fermilab's website [fnal.gov] has an article about the discovery.
Re:Implications regarding the Standard Model? (Score:2, Interesting)
Re:Implications regarding the Standard Model? (Score:4, Informative)
The mass deltas are known as squared values -- the sign is unknown, so there's the question of overall mass scale plus the ordering of the various flavors.
New discovery != string theory (Score:3, Interesting)
One thing I feel obligated to point out, however: this has nothing to do with string theory. String theory is a framework for thinking about how to unify the known Standard Model wit
explanation about oscillation/mass relationship (Score:3, Informative)
I hate when people act as if a complicated issue is simply true. So, as a public service to the Slashdot community:
Here is a site that attempts to explain it. [uci.edu]
My quantum physics knowledge isn't teriffic. Any particle physicists know of a better source?
Re:explanation about oscillation/mass relationship (Score:5, Informative)
A physicist on the recent Nova special "The Ghost Particle" (Maybe it was Boris Kayser) had a nice explanation. If neutrinos have no mass, then they travel at the speed of light. If they travel at the speed of light, then they would not experience "time". Since changing flavor is a process that takes time, or duration, or something like that (this previous clause is maybe a non-trivial thing to say), then if neutrinos change flavor, they must experience time, so they must travel slower than the speed of light, so they must have some mass.
Re:explanation about oscillation/mass relationship (Score:2)
More attention required (Score:2)
Re:explanation about oscillation/mass relationship (Score:2)
You can do a google search for arXiv:hep-ph/9905257 or the URL for the PDF is http://www.int.washington [washington.edu]
Re:explanation about oscillation/mass relationship (Score:2)
As you know mass enters equations through kinetic energy - mv^2/2
If you have several particles then their kinetic terms add up - and you get a diagonal matrix for mass.
A question comes up though is why are we sure that particle 1 is really particle 1 and not 99% particle 1 and 1% particle 2 ?
Mixtures can happen and do happen very often. Consider a photon and an electron - two particles we can usually separate pretty easily. However, if a photon travels
simple explanation (Score:4, Informative)
ponies, straight, gay? (Score:2)
Re:ponies, straight, gay? (Score:2)
Re:ponies, straight, gay? (Score:2)
Ouch! (Score:2)
Another assumption: They stopped for lunch. (Score:2)
Or, some of the neutrinos stopped along the way to have a beer.
Actually, it confirmed nothing except that fewer neutrinos were detected. It is utterly foolish to think that particle physics is enough understood that accurate guesses can be made.
Another topic, but still about this S
Re:Another assumption: They stopped for lunch. (Score:2)
Actually, particle physics is very well understood.
It was a long haul .... (Score:5, Interesting)
I joined the experiment in 1995 soon after the collaboration came together and created the proposal. In that time I've written simulation ("Monte Carlo"), reconstruction and framework code for the experiment. It's been a pretty exciting 10 years. The push to get everything together this last month has been exhausting. But after presenting the results on Thursday do we physicists take a well deserved break and party like 1999? Well, noooo. We spend Friday, Saturday and Sunday IN MEETINGS! Today (Saturday) we were there from 8:30am to 7:00pm discussing how further to proceed. We've got 50% more data "in the can" that we didn't yet present (cross checks to perform, fits to perform). Plus plans for more data taking after the accelerator comes up again in June. Plus other physics results we're still trying to extract. Plus more improved simulations to do in order to yield improved limits. Such is the life of a physicist.
Re:It was a long haul .... (Score:2, Informative)
I haven't seen mentioned any of the news reports point out the, ah, irony [no pun intended, well, okay, yes it was] of the "coal to Newcastle" aspect of transporting 5.4 kilotons of steel into an iron mine. I just like to point that out..
umm.. (Score:2, Funny)
Obligatory- (Score:5, Funny)
Why are they always prattling about missing mass? (Score:2)
ALL mass has gravitation - both rest mass and the mass equivalent of all the other forms of energy (including momentum) that go into the creation of the particle. So neutrinos have the same damned mass and gravitation whether they have rest ma
A Sad note (Score:5, Informative)
http://www.sciam.com/article.cfm?chanID=sa006&art
Neutrino (Score:2, Funny)
OH Great!!! (Score:3, Funny)
"To put it simply, if they are heavy, it means that there is a lot more mass in the Universe than we thought there was..."
So what this means is that people are really a lot fatter than what they think they are.
How I am a going to explain to my wife tomorrow when I say "Yes" to her saying "Am I fatter today?" - I'll pack my bags now and save myself some time. ummm, I may want to book a room too!
Chalk one up for Heim Theory (Score:2)
http://en.wikipedia.org/wiki/Heim_theory#Matter_an d_forces [wikipedia.org]
There are some empirical predictions of Heim theory which can in principle be experimentally verified, but this has not been achieved to date. These include
* Predictions for the masses of neutrinos, and
The mass for the neutron has been predicted by the formula a decade before experimental data existed.
Neutrino mass is important (Score:2, Interesting)
Star Trek (Score:2, Funny)
Re:Pardon me, but. . . (Score:2)
Re:Pardon me, but. . . (Score:5, Informative)
- Matter has mass and is made of particles.
- Light has no mass and is made of waves.
Nowadays it's more like this:- Fermions are wave-particles that have half-integer spin. Atoms are made of fermions.
- Bosons are wave-particles that have integer spins. Bosons are the things that carry forces.
All the familiar, everyday fermions have nonzero rest mass, and the only familiar, everyday boson -- the photon -- has zero rest mass. However, there are bosons that have nonzero rest mass (e.g., gluons), and it's also possible that there are fermions that have zero rest mass. (Experiments so far only measure the differences between masses of different types of neutrinos, so it's still possible that the electron's neutrino has zero mass.)Re:Pardon me, but. . . (Score:2)
So color symmetry is broken?
Re:Pardon me, but. . . (Score:2)
Weird, ha ?
Umm...a couple of corrections (Score:4, Informative)
Bosons don't necessarily carry forces; in fact not all atoms are fermions. For example, the Helium-4 and Carbon-12 nuclei is a boson. See wikipedia [wikipedia.org]. Bosons are best defined as having integer spin and being capable of sharing the same quantum state while fermions have half-integer spin and obey the Pauil Exclusion Principle (cannot share the same quantum state). A composite particle of an even number of fermions (2 protons + 2 neutrons) is a boson (helium nucleus) but an odd number of fermions is always a fermion.
I also believe that physicists have determined that the electron neutrino has a mass of about 1meV-1eV (from a slide I saw in lecture a couple days ago).
In addition, physicists divide fermions into quarks and leptons, which are supersets of the elementary particles that make up nucleons and electrons.
Re:That is nice and all (Score:2)
Re:Oh Derr! (Score:2)
in the end, einstein was right to only be sure about one thing being infin
Kinds of dark matter (Score:3, Informative)
When people talk about dark matter, they usually mean the exotic stuff, since there is a lot of evidence that the bulk of the universe's matter is exotic (look up "big bang nucleosynthesis" for
Mass and the speed of light (Score:3, Informative)