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I What can be Hawking radiated?

  1. Dec 19, 2017 #1
    A photon and a graviton are both certainly devoid of mass and charge.
    Therefore a massive black hole can certainly Hawking radiate either.

    Is the intensity of photon radiation and graviton radiation by a black hole exactly equal, or different at some specific proportion due to different properties of electromagnetic and gravitational fields?

    When can a black hole Hawking radiate a neutrino-antineutrino pair?
    Are neutrino-antineutrino pairs Hawking radiated at a flavour eigenstate (at some average mass), or at a mass eigenstate?
    There are observed square of mass differences with the two higher eigenstates. But is there a nonzero lower bound to the lower mass eigenstate of neutrino?

    If the lower mass eigenstate of neutrino has mass which is zero or nonzero but small compared to the mass of photons and gravitons emitted by black hole, what would be the power emitted as neutrino-antineutrino pairs compared to the power emitted as photons?

    And can a black hole have colour?
    Black hole has no hair. Only mass, angular momentum and electric charge.
    Colour is not a listed legal hair of a black hole.

    A gluon is supposed to have no mass. Even a small gluon mass would be supposed to disturb some observed symmetries (which?).

    If a gluon has no mass and a black hole no colour, what can stop a black hole from Hawking radiating a gluon? Because of no hair, the black hole has no colour to colour confine the colourful gluon!
     
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  3. Dec 19, 2017 #2

    mfb

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    A black hole emitting a gluon would get a color charge and the gluon would have a free color charge as well - it cannot do that. It can emit hadrons, but it has to be really small to have a relevant probability of that.

    It is not completely impossible that one neutrino type could be massless, in that case Hawking radiation would also contain neutrinos in addition to photons and gravitons. The powers are not equal due to spin states and so on, but they are of the same order of magnitude. It would be extremely weird to have one massless neutrino state, however.
     
  4. Dec 20, 2017 #3
    I was under the impression that Hawking radiation can be anything that is created in pairs? Why is mass a problem?
     
  5. Dec 20, 2017 #4

    mfb

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    Hawking radiation has nothing to do with pairs. Don't trust the pop science myths.

    The natural mass for the lightest neutrino would be around 0.01 to 1 meV, or 10 to 12 orders of magnitude above the temperature of stellar mass black holes. It can be much lighter or even massless, but that would be quite odd. The radiation is thermal, things with a mass of billions of times the temperature are not produced with any relevant probability.
     
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