Proton, anti Proton annihilation help

[shahbaz.c]

I have been told when a proton and anti proton annihilate only the one up and one anti up quark destroyed forming ∏+ and ∏- measons. I don't understand how both protons are not fully annihilated?

anti proton has:
anti up, anti up and anti down quarks
proton has:
up, up down quarks

Any help would be appriciated. :)

 

[Dickfore]

There are a number of channels in which this reaction can proceed.

 

[Dickfore]

I found the following referenc where baryon-antibaryon annihilation dynamics is discussed. You may follow other references from there:

http://arxiv.org/abs/hep-ex/0501020v1