Re: Do Color-Neutral Anti-Barons Act Very Weakly With Normal Matter?

Shawn,

First a little spelling correction: I think you meant to type "antibaryon", not "antibaron". Barons are quite heavy compared to elementary particles, tend to live in Europe, and are not color neutral (in fact a famous one was red).

An antibaryon is a color-neutral combination of three antiquarks each of which does carry a QCD color charge. An example would be an antiproton consisting of two antiup quarks and one antidown quark.

Even if particles are color neutral, they can still interact through the color force, also known as the strong nuclear force. For example, a color-neutral proton and a color-neutral neutron (both baryons) can bind through the residual strong interaction to form a deuteron. A good analogy would be two electrically neutral molecules interacting via the van der Waals force in chemistry.
http://en.wikipedia.org/wiki/Nuclear_force

When an antibaryon interacts with usual baryonic matter, the antiquarks in the antibaryon annihilate with the quarks in a baryon through the strong interaction. This is the reason that it is difficult to store antimatter for any length of time. The Tevatron collider at Fermilab stores three trillion antiprotons in a ring by steering them with a magnetic field through an evacuated beamline and not allowing them to touch any matter.

So the answer to your question is: no, an antibaryon, even though it is color neutral, will still interact through the strong nuclear force with ordinary baryonic matter, not just through the weak nuclear force.

--Dr. Randall J. Scalise http://www.physics.smu.edu/scalise