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Anti Proton vs Neutron annihilation

  1. Jan 16, 2016 #1
    Dear PF Forum,
    Just out of curiosity.
    What happens when an anti proton hits a 'normal' neutron?
    According to this:
    https://en.wikipedia.org/wiki/Proton
    https://en.wikipedia.org/wiki/Neutron
    A proton has 2 up quarks, 1 down quark
    A neutron has 1 up quark, 2 down quarks.

    1. Does anti proton has 2 anti up quarks and 1 anti down quark
    2. Can antiproton be annihilated with 'normal' neutron?
    3. Can anti up quark be annihilated with 'normal' up quark?
    4. So if anti proton can be annihilated with neutron what would the result? 1 anti up quark and 1 'normal' down quark?

    Thank you very much. Just out of curiosity
     
  2. jcsd
  3. Jan 16, 2016 #2

    ChrisVer

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    Gold Member

    yes. But these are called valance quarks. There is also a "sea of virtual quarks" and the gluons.

    annihilation in the sense of "disappearing" and giving photons, no. The proton would not be annihilated with an antiproton either. They can lead to hadronization however; eg pions.

    yes. For example the [itex]\pi^0 \rightarrow \gamma \gamma[/itex] is such an annihilation.

    there can be many ways for them to interact (especially with their gluons)
     
  4. Jan 16, 2016 #3
    Thanks ChrisVer for the answer
    But, please did you say the proton would not be annihilated with an antiproton either?Would you elaborate a little? Thanks.
     
  5. Jan 16, 2016 #4

    ChrisVer

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    Gold Member

    Simply put they will result to hadronization... if you want, you can consider it as annihilation but it's not that they give photons, they give hadrons [because QCD dominates]
    One example I found fast by google:
    http://teachers.web.cern.ch/teachers/archiv/HST2002/feynman/exampl14.gif
    [itex] p\bar{p} \rightarrow n \bar{n}[/itex]
     
  6. Jan 17, 2016 #5

    mfb

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    2016 Award

    Staff: Mentor

    The most likely result of a proton-antiproton collision at low energy is an annihilation-like reaction which produces a few pions and destroys proton and antiproton. As charge is conserved, the number of negative and positive pions is the same.
    The most likely result of a neutron-antiproton collision at low energy is an annihilation-like reaction which produces a few pions and destroys neutron and antiproton. As charge is conserved, the number of negative pions will be 1 larger than the number of positive pions.

    Very similar reactions.
    At higher energy, it is more likely that the collision still leads to baryons (can be the original ones, but different ones are frequent as well) plus additional pions.
     
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