1. Positron emission happens when an up quark changes into a down quark.

2. A proton contains two up quarks and one down quark; a neutron contains two down and one up.

3. The ground state up quark incompletely Annihilates with the ground state anti down quark to form a positron, [u.sub.0] + [ [bar.d].sub.0] [right arrow] [e.sup.+]

4. ‘Kaons and pions are examples of particles known as mesons, which contain a quark and an Antiquark.’ ‘A neutral pion consists of a down quark and a down Antiquark.’ ‘I've labeled the charges as q and q-bar for quark and Antiquark, but that's modern terminology that might not have been present in the early days of string theory.’