Talk:Neutrino oscillation

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[edit] math typo

I changed

\left| \nu_{a} \right\rangle = \sum_{a} U_{ai}^{*} \left| \nu_{i} \right\rangle\,

to

\left| \nu_{a} \right\rangle = \sum_{i} U_{ai}^{*} \left| \nu_{i} \right\rangle\,

because the former was obviously wrong. Someone with more knowledge should check if this is now correct. 193.171.121.30 11:27, 7 February 2006 (UTC)

Thanks. That was the right fix. linas 01:54, 8 February 2006 (UTC)

[edit] Neutrino Parameters and Their Values

Can anybody define these parameters? I guess they correspond to the angles that the mass and flavor eigenvectors form but they are never mentioned in the text. Poszwa 02:48, 20 March 2006 (UTC)

They seem to be at least somewhat explained now. What do you think? Strait 22:35, 13 July 2006 (UTC)

[edit] Fermions are matterparticles?

The article states that fermions are "matter particles". I think this formulation is awkward, since combining two fermions creates a boson, which could still be a matter particle. I think that comment should be removed. Andersa 12:16, 11 April 2006 (UTC)

Then be bold and remove it! —Keenan Pepper 13:55, 11 April 2006 (UTC)

[edit] Neutrino interference compared to oscillation

I went through a long discussion on PhysicsForums with a student who was convinced that neutrino oscillation was incompatible with the rules of physics, specifically conservation of energy. His problem was that the flavor eigenstate neutrinos do not have well defined mass, so he concluded that the process could not have well defined energies.

I finally got him to at least agree that neutrino oscillation was compatible with the assumptions of QM by describing the situation from the point of view of the neutrino mass eigenstates. See post 47 in http://www.physicsforums.com/showthread.php?t=115360&page=4

When looked on in this way, while flavor eigenstate neutrinos oscillate, the mass eigenstate neutrinos interfere. That is, all three mass eigenstate neutrinos contribute to the combined process of decay (in the sun) and absorption (at the detector), and since the experiment cannot distinguish which of the neutrinos was involved (as their masses are so very small compared to the energies involved), the rules of QM say that one must add together the diagrams for all three masses before computing probabilities.

The result is that the three massive neutrinos interfere with each other in the same manner as a photon interferes with itself in the 2 slit experiment. It's a great illustration of how the rules of QM are used in QFT.

I think that this should be added to the discussion for two reasons. First, it illustrates a principle of QM and Feynman diagrams. Second, it resolves the confusion in the student as to where neutrinos that oscillate go. Unfortunately, while this is all very obvious, I can't find a reference that explains neutrino oscillation in this way. Does that make it incompatible with Wikipedia standards?

I'd type up a short description but I hate wasting my time. Any comments?

Carl

This is a good idea. I will eventually get around to writing it up if no one else does first. Strait 22:36, 13 July 2006 (UTC)
Ok, I have made a graphical guide to neutrino oscillations. I have not (yet?) attempted to tackle the subtle quantum mechanical points, though. Strait 02:59, 8 August 2006 (UTC)

[edit] Expert

I think that I have added enough to this page to warrant removing the expert tag. If you disagree, please put it back and say why you did so here. --Strait 18:26, 7 August 2006 (UTC)

[edit] Flavor and mass do not commute

How can we describe the mass of any neutrino flavor since they are not mass eigenstates? I ask because there is a flavor - mass table at neutrino, which would seem a contradiction in terms. --Michael C. Price talk 07:57, 23 August 2006 (UTC)

The mass of a flavor eigenstate such as the electron neutrino can be defined as a weighted average of the masses of the mass eigenstates of which it is composed. For example, if the electron neutrino is 70% ν1, 20% ν2 and 10% ν3, then the mass of the electron neutrino is 0.7m1 + 0.2m2 + 0.1m3. I believe that this mass is the appropriate mass to consider when looking at direct measurements such as those gotten by observing the electron energy in beta decay. However, I think that for some phenomena such as neutrinoless double beta decay, the flavor eigenstate's mass must be defined somewhat differently. I will look into this and add information to the appropriate places when I get a chance. --Strait 21:00, 31 August 2006 (UTC)

[edit] Oscillations in matter

"I have added the probabilities of oscillations through solar matter. I used Runge Kutta method in maple to solve the coupled equations. I'll add the theoretical discussions soon. Please comment."

Since we know that there are three neutrinos that participate in oscillation, and we know fairly well what the relevant parameters are, I would prefer that the three neutrino model be used for specific real-life cases like propagation through the sun. The two neutrino framework is all well and good when the discussion is pure theory, but it's not actually what happens.

Once you're done writing the new section on solar oscillations, the section near the top called "Solar neutrino oscillation" should be edited to reflect the addition. --Strait 22:16, 27 November 2006 (UTC)

Oh, also, if you have a good understanding of the MSW effect, you might try to improve that page. (I only just barely understand it myself, so I don't want to try.) --Strait 22:18, 27 November 2006 (UTC)

[edit] Importance

This article has been rated as being of "low" importance. I think that a phenomenon which stems directly from the (apparently) fundamental parameters which define the universe, and is the only known way of measuring those parameters, should be rated at least "mid" if not "high". I think that this page is not well described by "Subject is mainly of specialist interest." --Strait 21:34, 11 December 2006 (UTC)

[edit] Article length

Adding all the graphs has started to make the article a bit long, in my opinion. Pictures help readers understand the content, so we should leave them. I would rather see something more technical move away. General readers might look at this article after the recent publicity including a NOVA episode devoted to the subject. We could consider reseparating the Maki-Nakagawa-Sakata matrix because it contains all the numerical details unappealing to general readers. This could also discuss experiments that attempt to measure the values. Notice how the Cabibbo-Kobayashi-Maskawa matrix has its own article. Teply 03:33, 19 December 2006 (UTC)

Agree, if it can be done elegantly. If you start the process, I will be around to help. --Strait 04:31, 19 December 2006 (UTC)
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