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Virtual particle

  1. May 22, 2008 #1
    Suppose there's an interaction AB -> CD, that goes via a virtual W boson, my question is, will the virtual boson leaves a track in the detector even though it's virtual ?
  2. jcsd
  3. May 22, 2008 #2


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    No is the short answer to your question.

    Think about what virtual means. A particle is virtual i.e "off mass shell" (violating energy conservation) for a time permitted by the uncertainty principle. Hence by definition it's impossible to "resolve" a virtual particle. Hence the name virtual.
  4. May 23, 2008 #3


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    if it was detected, then it would not be an interaction ab-cd since the W have to interact with the matter in the detector.
  5. May 23, 2008 #4
    Just to clear up some doubts... If it's a virtual particle produced in the s-channel say, the whole AB->CD interaction will be happening at one contact point, ie, four tracks (due to ABCD), unlike say AB->2 photons, and this photon flies off some distance before it interacts with the detector to give electron-positron pair, which in this case, there is two contact point, first ABphoton and the other point, photon-electron-positron.
    Sorry for my bad English.
    If it was a real particle on s-channel, then, the interaction point will differ in principle from the decay point, unless the detector has insufficient resolution power.
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