Proton-proton inelastic cross section in MeV

  1. jcsd
  2. mathman

    mathman 6,754
    Science Advisor
    Gold Member

    I am not familiar with the particular interaction. However I wonder if at those energies the only reaction is elastic sacattering?
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  3. mfb

    Staff: Mentor

    The first inelastic collision via the strong force should be pion production at ~150 MeV, probably with a negligible cross-section at this energy.

    p+p -> p+n+positron+antineutrino (or deuterium instead of p+n) would have a lower threshold, but as the process happens via the weak interaction the cross-section is completely negligible.
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  4. p+p -> d+positron+neutrino should have NO threshold, because it releases energy - but also a low cross-section because it is weak interaction.

    But there should be some electromagnetic interaction inelastic collisions, because protons are charged.
    p+p -> p+p+γ... whether the energy of the said photon is γ, x-ray, UV, visible, infrared or radio waves. How does the cross-section of braking radiation compare wit the cross-section for elastic collision?
    Starting from threshold of 1022 keV, there will also be electromagnetic interaction of
    p+p -> p+p+e-+e+
    So in that region, how are the comparative cross-sections of elastic collision, braking radiation and pair production?
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  5. The question arose to me when I do a simulation on FLUKA,
    there is inelastic scattering length 9.1E9 cm of proton-proton(H) in 10MeV.
    9.1E9 cm which converting to 0.011mb. Material.JPG
    It is really small compare to other process or elastic scattering of p-p.
    I just wonder where could I find other resource to compare with it ?
  6. mfb

    Staff: Mentor

    Right. But below the MeV scale you need long-range tunneling, and the cross-section gets even worse.
    Completely negligible when you want to simulate processes in FLUKA.

    I don't think they are called inelastic in high-energy physics, but that's probably just a question of definitions.

    Right. Again, should be completely negligible.

    I don't see 9.1E9 in this table, but this is scattering at hydrogen, not at protons. Ionization could count towards the value, or the result is just a relict of some extrapolation.
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  7. I'm sorry for 9.1E9cm, should be 0.16E+10 cm , converting to 0.11 mbarns.
    Also, it should be hydrogen instead of proton.
    However, is there other resources to compare ?
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