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Chronology of Universe.

  1. May 29, 2014 #1
    Most of the surviving electrons and positrons annihilated each other, releasing gamma radiation that briefly reheated the universe. So as we know Quark-Gluon Plasma was created during the Reheating Phase (which means quarks were formed during reheating phase). That means electrons were existing before Reheating. Which proves electrons existed before quarks. But I tried searching on the internet and I could find out that both leptons and quarks came into existence at the same time. Did electrons form before quarks?
     
  2. jcsd
  3. May 29, 2014 #2
    No one really knows the pre-inflationary particle dynamics, we simply do not have a complete theory of GUT. However at extremely high temperatures in GUT the quarks, leptons and fermions are in thermal equilibrium with one another. This is true even in the SuSy models and SO(10) models During the Grand Unification Epoch, physical characteristics such as mass, charge, flavor and color charge were meaningless. (key note the period here is also often described as a quark gluon plasma, although the makeup is SuSy particles). We still do not understand the particle physics at this stage, so the answer depends on SuSy or SO(10). I haven't studied the non Susy SO(10) GUT to know how this one works.
    the particles of Susy have not yet been observed, so we cannot say with certainty

    Then inflation occurs, The rapid expansion of spacetime meant that elementary particles remaining from the Grand Unification Epoch were now distributed very thinly across the Universe. However, the huge potential energy of the inflation field was released at the end of the Inflationary Epoch, repopulating the universe with a dense, hot mixture of quarks, anti-quarks and gluons as it entered the Electroweak Epoch.

    The key thing to remember in GUT, is that its not so much that elementary particles are created, its that they drop out of equilibrium or become distinquishable (decouple, freeze out).

    Electrons are present however they freezeout after the quark gluons start to form hadrons.
    this is from wiki "In particle physics, supersymmetry (SUSY) is a proposed extension of spacetime symmetry that relates two basic classes of elementary particles: bosons, which have an integer-valued spin, and fermions, which have a half-integer spin.[1] Each particle from one group is associated with a particle from the other, called its superpartner, whose spin differs by a half-integer. In a theory with perfectly unbroken supersymmetry, each pair of superpartners shares the same mass and internal quantum numbers besides spin - for example, a "selectron" (superpartner electron) would be a boson version of the electron, and would have the same mass energy and thus be equally easy to find in the lab."

    http://en.wikipedia.org/wiki/Supersymmetry

    however as noted no super symmetry particles have been observed.

    SUSY is SU(5)* SU(3)*SU(2)*U(1) the SM group is SU(3)*SU(2)*U(1) so all your standard model particles become super symmetric particles on the Susy scale.

    sticking to the standard model however here is a break down

    http://www.nicadd.niu.edu/~bterzic/PHYS652/Lecture_13.pdf
    hope this helps

    edit forgot to note one other key problem
    "In particle physics, an elementary particle or fundamental particle is a particle whose substructure is unknown, thus it is unknown whether it is composed of other particles.[1] Known elementary particles include the fundamental fermions (quarks, leptons, antiquarks, and antileptons), which generally are "matter particles" and "antimatter particles", as well as the fundamental bosons (gauge bosons and Higgs boson), which generally are "force particles" that mediate interactions among fermions.[1] A particle containing two or more elementary particles is a composite particle."

    http://en.wikipedia.org/wiki/Elementary_particle

    S0(10)*SU(5)*SU(3)*SU(1)*U(1), the SU(10) portion is esentially the Higg's sector, however it requires Higg's bosons of mass values we have not yet observed. Such as 54 Higg's 78 higg's 45 higg's, 154 higg's. There are numerous Higg's field variations and we so far have only observed the 126 Higg's with certainty. So the S0(10) group is uncertain at this time. However it essentially is involved on when particles first gain mass. The Higg's sector has a seesaw mechanism so does SO(10) There is numerous SuSY(10) and non SUSY (10) models and variations here is a review of them

    http://pdg.lbl.gov/2013/reviews/rpp2013-rev-higgs-boson.pdf
     
    Last edited: May 29, 2014
  4. May 29, 2014 #3

    bapowell

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    This is not standard terminology. What do you mean by "reheat the universe"? The term "reheating" refers to the short epoch following primordial inflation during which the inflaton decays into all the matter that makes up the hot big bang, including quarks, leptons, and their antiparticles.
     
  5. May 30, 2014 #4
    Reheating used twice

    Wait a minute I think reheating is used twice in the chronology of the universe. One is the reheating phase which occurred after Inflation field decayed into heat and radiation, causing quarks, electrons, and neutrinos to form. (Note also electrons to form). All this upto lepton epoch happened in 10 seconds from the big bang then later 15 seconds after the big bang electrons and positrons annnihilated each other briefly reheating the universe (Reheating for second time). Please help if you know more about it.
     
  6. May 30, 2014 #5

    bapowell

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    I'm not disputing the sequence of events, just that saying that electron-positron annihilation "reheats" the universe is not standard terminology, nor is it a good descriptor. In what sense does it "reheat" the universe? Reheating following inflation really does "reheat" the universe in that the post-inflationary universe is cold and empty, and after inflaton decay it is hot and full of matter.
     
  7. May 30, 2014 #6
    Electron Positron annihilation creates gamma ray photons (Pair of those). In this way universe is reheated because those gamma rays are of high energy.
     
  8. May 30, 2014 #7

    bapowell

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    But the energy is the same as the sum of the electron positron pair. Perhaps you should define what "reheating" means to you -- you keep saying it but so far have not distinguished it from something giving something else energy.
     
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