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How do I write a nuclear equation for the annihilation of a positron?

  1. Feb 17, 2008 #1
    How do I write a nuclear equation representing the annihilation of a positron with an electron?

    Do they just cancel out? or do I write energy on the left hand side of the equation?
  2. jcsd
  3. Feb 17, 2008 #2
    When an electron and a positron annihilate eachother, they produce a pair of photons. The photons conserve energy, and by having two of them, they conserve the momentum of the initial particles as well.
  4. Feb 17, 2008 #3


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    Science Advisor

    When you work in the center of mass sytem, you will get a pair of 511 kev photons going off in opposite directions - the direction is otherwise free.
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