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CP Violation in Neutral Kaon Decays

  1. Jun 25, 2015 #1
    I was recently reading an article that attempted to explain how the results of the Cronin-Fitch experiment illustrated CP violation. (http://hyperphysics.phy-astr.gsu.edu/hbase/particles/cronin.html) However, it wasn't very well explained. Could someone please explain this to me?
  2. jcsd
  3. Jun 26, 2015 #2


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    What did confuse you?
    The Kaon decay modes are explained in terms of K-short and K-long. These states are CP-eigenstates.
    These can either decay to a 2 or 3 pion products. The 2,3 pion products have different CPs.
    The 2 pions have CP=1 while the 3 pions systems dominantly have CP=-1.
    If CP is conserved, Kshort and Klong, having different CPs, would decay only to 2 pions (the CP=1 Kshort) or to 3 pions (the CP=-1 Klong).
    So if you send your beam and let the Kshort decay, after a while you only have Klongs in your beam and those will decay to 3 pions alone... the fact that you measured a significant number of 2 pion decays, is showing you that there is CP violation.
    Last edited: Jun 26, 2015
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