# Quark - antiquark annihilation

Hi there!
If an electron collides with a positron, they will annihilate producing a photon. But what about quarks?
If an up quark collides with an antiup quark, do they produce a gluon or a photon?
I ask that because I'm studying the reaction:
$$\Pi^- + p \rightarrow \Lambda+K^0$$
where I suppose the antiup quark of Pi annihilates with the up quark from the proton and creates a gluon, which in turn decays into a pair strange/antistrange quark. Is it right?

http://en.wikipedia.org/wiki/Electron–positron_annihilation

Look here for starters. There is a nice diagram of to the right showing most of the reaction. Look at that for help. There are other links at the bottom that may help as well.

That accounts for elecetron/positron annihilation, but what about quark and antiquark? Do they produce a photon or a gluon?

I figured it was like in the diagram. Two photons (opposed) and a neutrino. Let me find a better breakdown page, if I can. I'm not clear what the quarks create, I'd assume the photons as you said (they create diametrically opposed particles).