If a hadron moves with a velocity close to that of light,
Feynman observed that it is collection of an infinite number of partons
which behave like independent massless particles with a wide-spread
momentum distribution. Feynman's partons have properties quite different
from those of the quarks.
1970, Feynman stated that
(1) hadronic spectra on Regge trajectories are manifestations
the degeneracies of three-dimensional harmonic oscillators, (2) and we should
try oscillator wave functions, instead of Feynman diagrams, for bound states
in the relativistic world.
When we solve a quantum-mechanical problem, what we really do is
divide the universe into two parts - the system in which we are interested
and the rest of the universe. We then usually act as if the system in
which we are interested comprised the entire universe.