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Do Neutrinos Have Mass?
amyjigglypuff writes "MINOS, a joint project between Fermi National Accelerator Laboratory and the University of Minnesota, is going to attempt to uncover the mysteries of the neutrino. Scientists plan to study the mass of neutrinos, whether they are stable or oscillate, and their electromagnetic structure. If they are found to have mass, it could prove that neutrinos are responsible for the cosmic "dark matter" that has baffled scientists for decades. Here is a link for scientists and a summary for the general public."
but only the really heavy ones.
All Troll + "offtopic" mods are meta moderated as "Unfair", because you abused the system.
I thought the missing matter was in all the packing materials for all the equipment the scientists kept buying to try and find the missing matter.
-73, de n1ywb
www.n1ywb.com
Neutrinos have mass? I didn't even know they were Catholic!
Scientists restrict study to entire physical universe; creationist
Yes, Neutrinos have mass. This is old news dude.
Neutrinos, I believe, count as WIMPs (Weakly Interacting Massive Particles), the current prime candidate for just what makes up dark matter.
The other theory is that of MACHOs (Massive Compact Halo Objects) - large chunks of presumably baryonic material in a large halo orbiting the Milky Way.
The two theories are not exclusive, mind.
Soylens viridis homines es
I attended a seminar where one group was attempting to measure neutrino oscillations and found convincing evidence that this happens. In order for neutrinos to oscillate, however, they would have to have some mass. In the model that they proposed, some neutrinos may have mass and some may not. Also, if super symmetry comes into play, you could potentially have some very heavy neutrinos. For some cutting edge theories consult the archives.
Okay, so according to that article, one type of neutrino is an electron.
That doesn't make sense, does it? I thought that the definition of neutrinos were that they had a neutral charge.
Karma: Chevy Kavalierma.
The three neutrinos are each associated with a lepton (electron, tau, muon). The electron neutrino indeed has no charge. Electron neutrinos are typically emitted in beta+ decays or electron captues, both events involving a nucleus swallowing or spitting out an electron.
"I'm so moist I'm sticking to the leather." -Kermit the Frog on The Late Late Show
These Ask Slashdot questions are getting tough. I've got no friggin' idea!
--riney
I remember at 117 Gev we had some higgs boson marks, but the results were just beneath the standard deviation. Now we have to wait till 2004 or 2005 till the commecement of the LHC to be sure.
But the LEP results were close, and many scientists and nonscientists like myself are convinced we have it in that range. At least some neutrinos do have mass.
"Give orange me give eat orange me eat orange give me eat orange give me you." -Nim Chimpsky
I *knew* sex was cosmic!
You are being MICROattacked, from various angles, in a SOFT manner.
I'm doing a study into the intelligence of slashdot readers vs k5 readers for my Phd and I was wondering if you could all have a go at answering this question for me to help with my thesis conclusions
Imagine you have 2 waves, the sources of which are infinitely far apart. Now the 2 waves are 180o out of phase and so completely destructively interfere. My question is thus. Where does the energy go?
All that glitters has a high refractive index.
neutrinos have mass
neutrinos are not dark matter
scientists remain curious
If the sources are infinitely far apart, the waves never meet to interfere. Next question?
/. and K5 readers. :-)
And what do you do about doubled
I've had this sig for three days.
They've already proven neutrinos have mass [they even had a nightline episode dedicated to it]... and if im not mistaken, scientists have proven it does not make up _all_ of the dark matter.
I'm a signature virus. Please copy me to your signature so I can replicate.
is that they carry away a significant portion of the energy that stars emit. Something on the order of a few % of the Sun's power is radiated away through neutrinos. Neutron stars cool down because their energy is carried away by neutrinos. It really gets cool in supernovae, because as much as 40% of a supernova's energy is in the form of neutrinos. I believe that this can be detected in theory, but I don't remember if it ever has been.
Another neat thing is that there may be a 4th neutrino that does not interact via the weak force. Imagine that! It has already been said that a neutino is as close to nothing you can get and still have something, but a neutino that does not weakly interact is virtualy undetectable!
Cool stuff, if you like physics.
PIFMA-GASP
Don't Bogart the fish sticks
However, neutrinos are not sufficient to account for dark matter, and dark matter itself is not sufficient to account for the observed deviations of the shapes of galaxies from what is expected.
He mentions a tunnel that the nutrino passes through because it needs a straight-line path. How long is this tunnel? Any idea how much it cost to build?
I've actually been working as an undergrad assistant in a lab at UT Austin that is very active in the MINOS consortium, so it's pretty cool to see the experiment getting some attention.
;)
There are some neat photos of the detector; the steel scintillator modules weigh about 5,000 tons (!), and you can see one as it is lifted into place. The detector uses something like 2000 16 channel photomultiplier tubes (I don't remember the exact number of tubes) to detect the showers of particles that are created as neutrinos interact with the steel scintillator plates, and the data from those tubes is processed to reconstruct events. Did I mention that the whole thing is in a cavern about 1/2 mile underground to reduce background noise from cosmic rays?
The detector is supposed to come online and start collecting real data in 2004.
Another very interesting neutrino experiment is SNO, the Sudbury Neutrino Observatory, which is in an underground mine in Canada. SNO resolved the solar neutrino problem; people previously couldn't explain why we weren't seeing the right number of neutrinos coming from the sun - it turns out that they "oscillate" and change into other types of neutrinos, and SNO verified this. The neutrino oscillations also imply that they have a non-zero mass (explanation beyond the scope of this comment
The point of MINOS is to observe neutrinos from a controlled high-energy accelerator beam, rather than whatever we get from the sun, to very accurately measure the oscillations.
"They may have mass, they can hide - but we are gonna smoke them out!", Mr. Bush said during his Fermilab lecture.
e rr or.html
http://www.lns.cornell.edu/~neubert/bush_finds_
I doubt that we will ever figure out - and I suspect that even if we did figure out we couldn't do much about it
This is all fine and dandy in a cartesian universe, however in a non cartesian universe this is contradictory. Yeah, YEAH. This can only work in a cartesian universe. In a cartesian universe using euclid the *equal* and *opposite* is in a straight line.
The logic problem with this is, in the universe we appear to live in, has the *equal* and *opposite* reaction describing a curve. If something describes a curve, it usually ends up back where it started. Where did the opposite go?
Newtonian gravitational theory assumes that gravity is only a function of the attraction between two atoms and is not seen as a function of how those atoms are moving.
Voyagers mysterious slowing down, contra to newtonian celestial mathematical predictions, is an indication that all is not well with our mathematical model of the universe, not to mention the missing mass problem.
Newton's equations worked very well, until one tried to predict the orbit of mercury with them. Mercury inconveniently ignored Newton and everybody looked the other way for three hundred years, after all what what is one minor inconsistancy in such a wonderful set of equations.
Along came Einstein and suddenly mercury started to behave mathematicaly. I must have ploughed through about four biographies on Einstein and every biography I read seemed to be saying the same thing, that being, until his dying day he stated he could never fit gravity into his equations. Looking for evidence for gravity in the atom AKA 'quantum gravity theory' might miss the possibility that a mobius strip might have only one side kinetcally.
It's called an elephant's trunk whereas it is in fact, an elephant's nose, a nose by any other name would smell as sweet
Cosmic Gall
by John Updike (1963)
Neutrinos, they are very small.
They have no charge and have no mass
And do not interact at all.
The earth is just a silly ball
To them, through which they simply pass,
Like dustmaids down a drafty hall
Or photons through a sheet of glass.
They snub the most exquisite gas,
Ignore the most substantial wall,
Cold-shoulder steel and sounding brass,
Insult the stallion in his stall,
And, scorning barriers of class,
Infiltrate you and me! Like tall
And painless guillotines, they fall
Down through our heads into the grass.
At night, they enter at Nepal
And pierce the lover and his lass
From underneath the bed - you call
It wonderful; I call it crass.
You're thinking neutrons.
Slow Down Cowboy!
No, both neutrons and neutrinos carry no charge, but they're different particles--neutrons are baryons (made from three quarks), whereas neutrinos are leptons.
The mass of a neutrino is equal to zero, for very large values of zero.
They can't be 180 degrees out of phase everywhere and at all times. For example, consider the portions of the wave directly between the two sources. They propagate toward each other and thus you get a standing wave at twice the amplitude of either one (assuming they each have equal amplitudes). In fact, the only place where you could get perfectly destructive interference is directly behind a source, as seen from the point of view of the other source.