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The earliest Photons

  1. Sep 25, 2013 #1
    Where there photons around in the electroweak era?

    I read that
    The CMB photons travel through the universe relatively unimpeded untill recombination when the atoms formed and before this they were being scattered. Were they around in the quark anti quark gluon plasma?

    I am also interested in what is meant by neutrino decoupling

    Thanks for any information

    Mr C
    Last edited: Sep 25, 2013
  2. jcsd
  3. Sep 25, 2013 #2


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    Photons were around since the bigbang. However until the universe cooled down they were constantly interacting with the charged particles making up the plasma.
  4. Sep 25, 2013 #3
    Thanks for the response
    So did the quarks and anti-quarks and the electron positron pairs come into existance from pairs of photons or both pairs of photons and gluons?
    I appreciate the answer as this helps plug the holes in my limited knowledge
  5. Sep 26, 2013 #4


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    Electron (positron) pairs come from photon pairs. Quarks and gluons are a little over my head. At high enough energy photon pairs could lead to proton (antiproton) pairs.


    The above should help.
  6. Sep 26, 2013 #5
    Brilliant thanks for this lead. I have also dug out my first three minutes by Weinberg.
    I am happy that there is a time when photons are making baryons and fermions and as the temperature cools then this conversion and anhillation stop and a residual amount of matter remains. What I can't seem to find any information on is when the Universe was even hotter and there were quark anti quark pairs and gluons, were there photons and the bosons associated with the weak force then as well as the gluons, or does this stage have the gluon as the only boson. So the photons appear when the symetry is broken and the electroweak force and strong force seperate.
    This may not even make sense.

    Thanks for your responses so far
  7. Sep 27, 2013 #6


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    I don't have material to help you in general. My understanding is that photons were there from the very beginning.


    The above is what I got from Google. There should be something useful.
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