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Offline chris

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What are neutrinos?
« on: 24/12/2009 04:02:22 »
What are neutrinos and what is their role in atomic structure? How are they produced?


 

Offline neilep

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What are neutrinos?
« Reply #1 on: 24/12/2009 13:24:02 »
What are neutrinos and what is their role in atomic structure? How are they produced?



 

Offline JP

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What are neutrinos?
« Reply #2 on: 24/12/2009 13:49:12 »
I think neilep's on to something there! ;D

But in seriousness, neutrinos are point-particles within by the standard model of particle physics.  They don't have any sub-structure.  They arise from nuclear reactions and are important for conserving momentum in those processes.  That is in fact how they were discovered--momentum did not appear to be conserved in some processes and so Fermi(?) proposed that a previously unobserved neutral particle accounted for the missing momentum, and eventually it was observed. 

As for the more technical aspects of the neutrino, they have tiny (but almost certainly non-zero mass) and they come in three kinds.  They interact with other particles via the weak force and gravity.  Since they have low mass and are uncharged, they interact very weakly with other matter.  This means that doing experiments on them is very difficult, and usually consists of building giant detectors underground: http://en.wikipedia.org/wiki/Super-Kamiokande (most particles are blocked by the earth, but neutrinos generally pass right through it without interacting with anything).
 

Offline lightarrow

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What are neutrinos?
« Reply #3 on: 24/12/2009 14:13:27 »
If, one day, we'll manage to make very sensitive measurements of neutrino's beams, we'll have a fantastic instruments to look directly inside of stars (even a star is rather transparent for neutrinos) and, maybe, also inside of neutron stars.
« Last Edit: 24/12/2009 14:24:43 by lightarrow »
 

Offline chris

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What are neutrinos?
« Reply #4 on: 26/12/2009 11:01:45 »
But don't stars also produce many neutrinos, so how would you use them to "see inside" a star?

Chris
 

Offline Vern

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What are neutrinos?
« Reply #5 on: 26/12/2009 13:05:06 »
I predict that the final outcome will be that the neutrino particle does not exist. I suspect this because more and more excuses are needed to explain observations that do not fit the predictions.
 

Offline PhysBang

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What are neutrinos?
« Reply #6 on: 26/12/2009 14:08:25 »
I predict that the final outcome will be that the neutrino particle does not exist. I suspect this because more and more excuses are needed to explain observations that do not fit the predictions.
Can you name one?
 

Offline lightarrow

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What are neutrinos?
« Reply #7 on: 26/12/2009 19:51:38 »
But don't stars also produce many neutrinos, so how would you use them to "see inside" a star?

Chris
I intended exactly that. See, for example:
http://focus.aps.org/story/v7/st26
 

Offline Soul Surfer

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What are neutrinos?
« Reply #8 on: 26/12/2009 23:42:02 »
A neutrino is a lepton like an electron but it has no charge.  The only property that it has is angular momentum in the form of "spin" as has already been said it probably has a very small mass.  it is usually "detected" indirectly  in that it is accounted by energy and momentum missing in a fully measured nuclear interaction.

Beams of neutrinos can be produced and detected by positive interactions and there is absolutely no doubt that these particles do exist even though they are very elusive.

The next generation of dark matter particles will be much more difficult to detect but the odd are quite reasonable that they will soon be detected.
 

Offline yor_on

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What are neutrinos?
« Reply #9 on: 27/12/2009 03:43:53 »
Sorry, neutrinos not neutron. I knew there was something I missed ::))

But I can dance it :) The Neutron dance I mean, possibly?

---

http://hitoshi.berkeley.edu/neutrino/PhysicsWorld.pdf



« Last Edit: 27/12/2009 03:54:59 by yor_on »
 

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What are neutrinos?
« Reply #9 on: 27/12/2009 03:43:53 »

 

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