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Why is the Z vector Boson heavier then most quarks?

  1. Feb 6, 2006 #1

    If we use the Friedman Equation form to find time(excpected) for a given particle's Rest Mass energy as our input value, does it mean that the most energetic particles were 'born' first and the lighter particles 'born' later on in time in a linear, sequential order?

    eg. T quark (174Gev)---->Z Boson(~90GeV)----->W Boson(~80GeV)---->B Quark(5GeV)------>Tau(~1777MeV)-----Proton(~938MeV)----->Electron(0.511MeV)------>etc...

    Does the order of their Rest Mass energies mean they were 'born' in that order too?

    Thanks, I'm very puzzled about this.
    Last edited: Feb 6, 2006
  2. jcsd
  3. Feb 7, 2006 #2


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    Nobody knows, You get Z and W from Fermi constant plus the electroweak couplings. The puzzling thing to me is why is the Z, W, and Top quark so much heavier than the other quarks. Besides, there Top quark relates also naturally to Fermi constant in the sense that the Yukawa coupling giving mass to this quark is exactly unity, a misterously casual thing.
  4. Feb 11, 2006 #3
    hold on rivero

    Does a particle's rest mass dictate when it appeared in the Universe?

    ie. electron and positron production occured at times before the average photon's kT>1MeV

    So does that mean that earlier on in time photons with kT>348GeV (174GeV x 2) were creating Top Quark/ anti-Top Quark pairs? Can we generalize that all particles are created from photons at various stages in the Universe's Energy densities?

    I found your last answer useful, but it wasn't completely satisfying.
  5. Feb 12, 2006 #4


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    There is a biannual review about cosmology, you can check it and references therein. I am not very conversant in this area. Enjoy.
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