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Electron-positron pair creation by weak interaction?

  1. Dec 17, 2008 #1
    Hello,
    Im trying to find out if, since an electron positron pair can anhillate to produce a muon-anti muon pair by the weak interaction, can the same thing occur for the production of an electron/anti-electron pair? Or would it just happen by the electromagnetic force? Or both, with the weak being supressed? And are the photons/ Z0 bosons involved real or virtual?
    I feel as if I am asking a question I should know the answer to and being silly, but any help would be appreciated!
    Thanks!
     
  2. jcsd
  3. Dec 17, 2008 #2

    malawi_glenn

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    e+e- -> e+e- via Virtual Z^0 is ok.
     
  4. Dec 17, 2008 #3

    jtbell

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    It's simply very rare because the mass of the Z_0 suppresses the cross section. I think some experiments do study contributions from Z_0 exchange in certain processes (maybe even e+e- scattering), as tiny corrections to a pure photon-exchange model.
     
  5. Dec 18, 2008 #4
    Thanks, thats very helpful!
     
  6. Dec 18, 2008 #5
    The technical term for this process is "Bhabha scattering":

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

    If the electron and the positron are nearly at rest, Z contribution is significantly suppressed because the intermediate virtual Z is way off mass-shell. At high energies, both are important. At CM ~ 90 GeV, Z exchange will most likely dominate.
     
  7. Dec 18, 2008 #6

    jtbell

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    Staff: Mentor

    Indeed, the old Large Electron Positron (LEP) collider was originally designed for a CM energy in that range, specifically to produce the Z_0.
     
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