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I Which baryons can annihilate?

  1. Jun 30, 2017 #1
    Different baryons routinely annihilate. Like antineutron and proton.
    Wikipedia article on annihilation acknowledges this.
    But at
    near end of first section, I find statement:
    The most common (lowest energy and longest lifetime) baryon that shares no flavour with nucleons is omega hyperon.
    Annihilation of antiomega hyperon would be energetically favourable. 1672 MeV of Ω plus 938 MeV of proton sums up to 2610 MeV, while 3 kaons would be just about 1490 MeV.
    So, does antiomega hyperon have a conspicuously lower annihilation cross-section and longer lifetime in matter compared to other antihyperons which do share quark flavours with nucleons?
  2. jcsd
  3. Jun 30, 2017 #2


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    Staff: Mentor

    ##\Omega## has a lifetime of 82 ps, corresponding to a few millimeters to centimeters of flight distance, and we cannot produce it at low energies (with relevant cross section). It decays before we could observe low-energetic annihilation reactions.
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