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Spin projection operator

  1. Nov 16, 2012 #1
    I cannot quite understand why expression [itex] \frac{1-\gamma_5 \slashed{s}}{2} [/itex] is covariant? We defined it in the rest frame, and then said that because it is in the slashed expression, it's covariant, what does that mean? s is the direction of polarization, [itex] s \cdot s = -1 [/itex]
    Last edited: Nov 16, 2012
  2. jcsd
  3. Nov 17, 2012 #2
    Figured it out, one should use the identity [itex] \hat{S}(\hat{a}) \gamma^\nu \hat{S}^{-1} (\hat{a}) = a_\mu ^{\text{ } \nu} \gamma^\mu [/itex], the rest is straightforward.
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