author – Daniel Miller
To follow the reference list from the previous page, whole strory is based on the idea that
proton is made of u, u, d and sea of u – \bar u and d – \bar d quarks and quark pairs
neutron is made of d, d, u and sea of d – \bar d and u – \bar u quarks and quark pairs
isospin rotation (proton to neutron) is just rotation of d to u
How many \bar d and \bar u quarks are in proton? `how many in neutron? It is not known, particularly because most of energy is taken by gluons. In the same time people discuss \bar d to \bar u ratio in both protons and neutrons. Muon scattering data indicates that it is not one, and assumption is that neutron has opposite to proton \bar d to \bar u density ratio.
Daniel L. Miller Works Collection 