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Confused about antimatter and matter

  1. Jun 13, 2007 #1
    Matter/ Antimatter
    proton/ positron

    is that right? So can you tell me there properties? '
  2. jcsd
  3. Jun 13, 2007 #2


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    No, you have this all wrong.

    The antiparticle of a proton is antiproton
    The antiparticle of an electron is a positron.

    Please go to the Hyperphysics website to learn some basic ideas on antiparticles


  4. Jun 13, 2007 #3


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    Good Kirk/Evil Kirk

    Antiprotons are just like protons except they have a negative charge.
    Positrons are just like electrons except with a positive charge.
    Photons are neutral. You cannot tell from the photons emitted whether it came from matter or antimatter. Thus, light coming to us from distant galaxies does not tell us (at least directly) whether the galaxy is made of matter or antimatter.
  5. Jun 14, 2007 #4
    How can anti-neutrons be observed?
  6. Jun 15, 2007 #5


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    Particles are known to exist through interactions. An anti-neutron would annihilate a neutron with a meson shower, i.e. + and - mesons, and perhaps neutral pairs, going in various directions.

    Neutral particles are unobservable since they do not ionize as charged particles do, although neutrons can knock protons and nuclei about, which can be observed.
  7. Jun 18, 2007 #6
    IIRC, there is another property that is different, besides charge, but this difference doesn't usually receive much attention, presumably because the property is not well known to the general public.. Unforetunately, I don't remember what that property was. Anyone cares to freshen my memory - and enlighten the other readers while they're at it?
  8. Jun 18, 2007 #7
    spin? Isn't that the reason that the charge is different in the first place? (spin = helicity?)
  9. Jun 18, 2007 #8
    That was my first thought too, but according to http://en.wikipedia.org/wiki/Antiparticle the spin is the same:
    Plus, if memory serves, it was some more exotic property (or seemed so to me when I read about it somewhere a long time ago), even less well known than spin. Maybe baryon number or some such...
  10. Jun 18, 2007 #9
    Flavour of their quarks? Delicious. :)
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