Fewer neutrinos arrived at the detector in Soudan than expected
Posted on 03/31/2006 6:04:35 AM PST by The_Victor
Physicists have confirmed that neutrinos, which are thought to have played a key role during the creation of the Universe, have mass.
This is the first major finding of the US-based Main Injector Neutrino Oscillation Search (Minos) experiment.
The findings suggest that the Standard Model, which describes how the building blocks of the Universe behave and interact, needs a revision.
Neutrinos are believed to be vital to our understanding of the Universe.
But scientists know frustratingly little about these fundamental particles.
The findings build on work carried out by Japanese physicists.
Different 'flavours'
Neutrinos are sometimes described as "ghost particles" because they can pass through space, the Earth's atmosphere and the Earth itself with almost no interaction with normal matter.
This makes studying them very difficult.
There are three kinds - or "flavours" - of neutrinos: muon, tau and electron.
To examine their properties, scientists created muon neutrinos in a particle accelerator at the Fermi National Accelerator Laboratory (Fermilab) in Illinois, US.
A high intensity beam of these particles was fired through a particle detector at Fermilab, and then to another particle detector 724km (450 miles) away in a disused mine in Soudan, US.
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Fewer neutrinos arrived at the detector in Soudan than expected
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"Because they so rarely interact with matter we can shoot them straight through the Earth, and most will travel through without doing anything," explained Dr Lisa Falk Harris, a particle physicist at the University of Sussex, and a member of the Minos team.
"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."
The scientists' set up established that fewer particles were being detected at the Soudan site than had been sent. They had effectively "disappeared".
"What they have done is to convert into another type of neutrino," Dr Falk Harris told the BBC News website.
Physicists call the process of transforming from one type of neutrino into another flavour oscillation. And to be able to perform this transformation, particle physics theory states that the particles need mass.
"The fact that we see them 'disappear' and they do this little transmutation, means that they must have mass," said Dr Falk Harris.
'Missing mass' mystery
These are the first results from the Minos experiment, which has involved scientists from 32 institutions in six countries.
It confirms the earlier observations of neutrino "disappearance" found in 2002 by the Japanese K2K experiment, where scientists fired muon neutrinos at a detector situated 240km (150 miles) away.
The corroboration that the neutrino has mass has profound implications for particle physics.
"In particle physics there is the Standard Model which describes how the fundamental building blocks of matter behave and interact with each other," explained Dr Falk Harris.
"And this model tells us that neutrinos should have no mass. So the fact that we have now got independent measurements of neutrinos saying that they must have mass, means that this Standard Model is going to have be revised or superceded by something else."
In the longer term, the findings may also help us to better understand the mystery of "missing mass" in the Universe.
"Various observations show there appears to be much more mass in the Universe than is visible," said Professor Jenny Thomas, a particle physicist at University College London, and a member of the Minos team.
"We are surrounded by neutrinos, so in every cubic centimetre there are hundreds at any instant.
"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."
Neutrinos are also thought to have played an important role in the formation of the Universe. The Minos findings and future ones may help to shed light on how matter formed, and why so much of the Universe's antimatter has disappeared.
They forgot to mention the other "flavour" of neutrino that was discovered by Italian scientists a while back. It was basically equal to the electron, ie, on par with it, and the named it the mesan. Now it is known as the parmesan particle and can be found at Italian resTAUrants everywhere......
Groan....
huh?
Good stuff. Thanks for the post.
More revisionist history from the neutrino lobby. Back during the Big Bang, it's well known that they steadfastly maintained their neutrality.
Oh, that's so bad it's good. Is it yours or did you borrow it?
Neutrinos have mass? I didn't even know they were Catholic!
CC
It has no matter, so they are like Christmas Catholics.......
MINE! MINE! MINE! ALL MINE!........All your neutrinos are belong to us!............
"And this model tells us that neutrinos should have no mass. So the fact that we have now got independent measurements of neutrinos saying that they must have mass, means that this Standard Model is going to have be revised or superceded by something else."
More new discoveries and new ways of thinking. Science sure is hard to keep up with.
A news release from July 2004 about the discovery of neutrino oscillations. Incidentally, David Casper, one of the leaders of the team, is a conservative who was "outed" as a Bush supporter by The Scientist in the last election year.
The 1988 Nobel Prize in Physics press release, describing the first muon neutrino beam experiments, performed by Lederman, Schwartz and Steinberger.
And finally, the Soudan lab's official webpage We Gophers dig more than just tunnels :-)
Are those paremsan neutrinos related to another neutrino named after their discover Jedediah Oregon, who also went on to discover a Pacific coast state, and subsequently named oreganos?
So, neutrinos only have mass on High Holy days?
No, Those are Italian particles, too.........Part of the Spaghetti String Theory.......
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I love a good pun. My hat is off to you.
Yes, that's why they don't get detected easily. They are so holey.......
Too early in the day for Physics puns....
Fewer neutrinos arrived at the detector in Soudan than expected.
Thanks.
But there are sevearl flavors of neutrality.
I will leave no pun un-dun.........
If an object doesn't have mass does it really exist?
"More new discoveries and new ways of thinking. Science sure is hard to keep up with.
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It is. There are always new discoveries, especially in subatomic physics. There's still much to learn, and we're learning it.
It's fascinating.
Swiss Baskin-Robins?.......
They got fewer hits at the remote detector than they expected. How do they rule out misalignment? It's hundreds of miles away. It's not like you can hold up a card to see where the beam is heading, like you can with a laser beam.
sevearl should be several
I get it. LOL!
O master Pundit, pundency is yours....
Balderdash--it's never too early for a really rotten scientific verbal stinker. And there've been some good ones here!
When seen with ultra sensitive scanning equipment, the neutrino is sitting in the back pews, reading the bulletin, and pretending like it remembers all the words to the confession of faith...
CC
ah, the pungency of punditry...
If that's correct, it makes one wonder whether theories about the cosmic background radiation would have to be revised....
No wonder they disappear so fast! They're closer to the doors!......
Then again, perhaps their tendency to change into other "flavours" provides long-awaited scientific support for transubstantiation....
Ugh! Too early here for that sort of shock... '-)
LOL! Clever.
Please define the following:
1) object
2) mass
3) exist
under the following systems:
1) Newtonian
2) Quantum
3) Logical Positivism
4) Metaphysics (of choice)
5) M-theory
If you do, you get a whole case of Parmesan particles.
That's actually the easy part. Now if they have mass does it mean that they have other than a flat trajectory?
No -- it means that your missing mass is not related to an unknowable "Dark Matter" anymore -- it's just in the neutrinos.
So long, Dark Matter -- it was nice knowing you. I love it when theories bite the dust, as it means true progress is occuring. I especially love it when bizarre theories bite the dust (the ones where you know they just pulled something out of their a** because they got tired of trying to figure out how to make the calculations work, like they did with dark matter).
Perhaps even, one day, macro-evolution.
and
The scientists' set up established that fewer particles were being detected at the Soudan site than had been sent. They had effectively "disappeared".
"What they have done is to convert into another type of neutrino," Dr Falk Harris told the BBC News website.
The conclusion does not seem to fit the facts here. How does the conclusion of "What they have done is to convert into another type of neutrino" fit conclusively with "Of course, most of them travel right through our detectors as well" ?
It seems to me that if they travel through the detectors without interaction, then you cannot say that they have converted into anything.
Thanks! I knew someone would, given the subject of this Thread. {*LOL*}
Maybe they ought to set up detectors within site along a path
and see how many get lost along the way. But then again,
since they pass through most of the time without reacting
how do you know ¡f your aim is bad, or that they just
didn't want to engage your detector...
It's difficult to track things which we can't detect!
BTW, what factors influence their ability to be detected or
not to be detected? Do they have a "cloaking" mechanism?...
oh, dear, more questions.
Of course.
I don't see what's easy about it. To answer your question, yes, their path would have to curve under influence of gravity - just like light does, which is even massless. But the curvature is extremely slight under a weak field like the earth's. The sun only deflects light grazing the surface a few seconds of arc, and that's over a distance a lot longer (!!) than a few hundred miles.
Back to the alignment question, how do they know they're in the center of the beam? They get one hit a day - a lot slower feedback than, say, shooting artillery. How do they even know what their beam divergence is?
Oh No. That would be the combination of the Spaghetti String Theory and the Do-Nut Hole Theory !............
Not necessarily. If the standard theory, (what one "expects") predicts a certain number, but another theory predicts fewer, and you do the experiment and it's fewer, it contradicts the standard theory and supports the other - without necessarily needing more funding.
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