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A question about mass eigenstates

  1. Aug 14, 2012 #1
    I am very confuse about mass eigenstate. In some books they say'' If neutrinos are massless then lepton mixing is unobservable.Any Cabibbo-like rotation still leaves us with neutrino mass eigenstates''.
    I do not understand that statement.Why the mixing of some states gives a state being mass eigenstate?
    Please forgive me if it is bad question,I have to self-study physics in Vietnamese society.
  2. jcsd
  3. Aug 14, 2012 #2


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    Staff: Mentor

    Without neutrino masses, every superposition of neutrino states is a mass eigenstate, and therefore remains this superposition. In particular, every flavor eigenstate is a mass eigenstate, and does not mix.

    With neutrino masses, the mass eigenstates can be different from flavor eigenstates. You can get 3 different mass eigenstates, and their flavor composition is given by the PMNS matrix (similar to the CKM matrix, just for neutrinos).
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