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Neutrinos penetration of neutron stars or white drawfs

  1. Mar 14, 2010 #1
    Neutrinos can pass through solid objects like the earth easily, and a light-year of lead would only stop half of them from passing through.

    What about something very dense like a white drawf or neutron star? How readily can neutrinos penetrate that? What % flux reduction would be achievable if neutrinos passed through a neutron star?
     
  2. jcsd
  3. Mar 14, 2010 #2

    bcrowell

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    The density of nuclear matter is greater than the density of ordinary matter by about a factor of 10^15. So I would guess the answer would be that neutrinos would penetrate into a neutron star by roughly (1 light-year)*10^-15=10 m.
     
  4. Mar 14, 2010 #3
    Is it the same for neutrinos and anti-neutrinos?

    Bob S
     
  5. Mar 14, 2010 #4
    thanks, according to this link it's 22 light years.

    Neutrinos
    This was an expected result, since the mean free path of a neutrino in matter is about 22 lightyears in lead and having the earth in the path makes little ...
    hyperphysics.phy-astr.gsu.edu/Hbase/particles/neutrino.html

    I'm not sure there's a linear proportion of density and penetration.
     
  6. Mar 14, 2010 #5
    From bcrowell:
    The density of nuclear matter is greater than the density of ordinary matter by about a factor of 10^15. So I would guess the answer would be that neutrinos would penetrate into a neutron star by roughly (1 light-year)*10^-15=10 m.

    From Bob S
    Is it the same for neutrinos and anti-neutrinos?

    I think that a neutrino incident on a neutron has an allowable final state (proton plus electron), while the anti-neutrino incident on a neutron has none. This should be reflected in the total cross section.

    Bob S
     
    Last edited: Mar 14, 2010
  7. Mar 15, 2010 #6

    Vanadium 50

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    Bob, Bob, Bob....<sigh>

    Again, you are adding complications that are unnecessary and confusing.

    The cross-section is what it is. If I have 1015 times as much material, the interaction rate goes up by this factor. This is all wrapped into the definition of a cross-section. Talking about the differences between neutrino-on-nucleon and antineutrino-on-nucelon is just muddying the waters.
     
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