Talk:Mikheyev–Smirnov–Wolfenstein effect

Our expectations for the MSW effect
I would like to raise a concern about the line: "For high energy solar neutrinos the MSW effect is important, and leads us to expect that Pee=sin2θ ≈ 30%". The Standard Model (augmented to accomodate neutrino mass and oscillation) has no expectation for this value. On the contrary, the mixing angle in question ("theta" here, "theta_12" in the neutrino oscillation article) is a completely arbitrary quantity in the SM. In fact, it is the observation of an MSW effect modulated survival probability of close to 35% which has allowed the determination of this angle to be somewhere close to sin^{-1} 1/sqrt(3). So, I propose to modify this sentence, unless others disagree strongly (in which case, we should discuss some more). Paulfharrison 07:44, 29 May 2007 (UTC)


 * Please do be bold and modify it as you see fit. In the meantime, I went ahead and replaced "leads us to expect" with "leads to the expectation". Second- and third-person references may be natural phrasing in a lecture, but are inappropriate for statements in an encyclopedia. —mjb (talk) 06:21, 3 July 2008 (UTC)


 * I like to consider myself a bit of a nuclear science nerd; I understand immediate, short, medium and long term effects of nuclear weapons, I know what a slow neutron is, I generally understand cherenkov radiation, - all in strictly non-mathematical terms - but this whole article is like a parsec above my head. Please, can someone sum up the effect in terms analogous to something else? If the chaotic dispersal of something v nothing in superclusters, galaxies, stellar distribution, etc down to faults in electrical transmissions and the atomic structure itself are all analogous and effectively self-similar, surely the MSW effect can be dumbed down AND its summary posted in the first line! —JJ (talk) 09:03, 4 February 2009 (UTC)

ν2 eigenstate
The term needs explaining. --Michael C. Price talk 19:29, 24 August 2006 (UTC)
 * I tried to clarify it. The page is still kind of confusing, though. HEL 21:11, 15 October 2006 (UTC)

Neutrino Interaction with Matter
I have read that "Neutrinos pass thru 30 light years of matter without interaction". As a matter of fact, I've read it in an introductury brochure of astrophysics.

How come, if neutrinos pass thru matter like nothing, there can be a "MSW resonace effect" within the sun? That's less than 1 million kilometers of matter in the sun! Phr en (talk) 08:05, 28 May 2008 (UTC)

The MSW effect is based on coherent forward scattering - which makes it very similar to the electromagnetic refraction of light in a medium. Thus, the neutrinos are not stopped or deflected in the interaction but their effective masses and mixing changes. The effect is still very small (proportional to the Fermi constant). However, the mass squared differences are also small and if the electron density is large enough, the coherent forward scatterings dominate the dynamics. I have edited the article to include the analogue to the refractive index. --Blennow (talk) 00:38, 19 October 2008 (UTC)

Symbols and their definitions
Eigenstates referred to by symbols: v1, v2, v2m, ve

Eigenstate symbols explicitly defined in the article: v2m - High mass eigenstate in mater, v2 - High energy state in vacuum

Other undefined symbols Pee —Preceding unsigned comment added by 71.235.249.245 (talk) 13:17, 13 September 2008 (UTC)