Is it possible, for a strong interaction of the above described type (baryon - anti baryon), to exist?

$$B + \bar B \to \ldots $$

(Where $B$ is a generic baryon and $\bar B$ the anti-)

Namely like a parallel exchange of 3 gluons, all with positive charges (of course)?

Some example?

Thank you!!


Yes, you can observe elastic proton-anti-proton scattering. Indeed, the cross section is not all that different from that of elastic proton-proton scattering. The main difference is that $pp$ is predominantly elastic at low energy, and dominantly inelastic at high energy, whereas $p\bar{p}$ is dominantly inelastic at all energies. Also note that inelastic high energy $pp$ and $p\bar{p}$ scattering are nearly indistinguishable. This means high energy $p\bar{p}$ scattering is not really annihilation, just elastic parton scattering followed by production of soft particles.

Cross section plots can be found here http://pdg.lbl.gov/2015/hadronic-xsections/.

  • $\begingroup$ That's a really interesting and useful answer, thank you. And speaking about gluons.. how does it works? Can gluons also be in a twosome with a whole positive charge? (don't know if it's clear..) $\endgroup$ – Les Adieux Jan 10 '16 at 17:43
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    $\begingroup$ @KimPeekII: the gluons are electrically neutral. They interact with the quarks and other gluons through the strong (color) force, not electromagnetism. At very high energies (short distances) the gluons and quarks are free, so scattering can happen with just the exchange of one quark or one gluon. This leaves the proton and antiproton colored, which has to be neutralized as they fly apart, leading to the exchange of some more quarks or gluons. Eventually the exchange has to add up to be colorless. $\endgroup$ – Ross Millikan Jan 10 '16 at 18:15
  • $\begingroup$ Right! How stupid I am. They are neutral, electrically. Oh I have one last question. Supposing I have a $bg$ gluon. How do I write it in the octet base? Thank you so much again!! $\endgroup$ – Les Adieux Jan 10 '16 at 18:27

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