We study the structure functions of hadrons with the low energy effective
theory of QCD. We try to clarify a link between the low energy effective
theory, where non-perturbative dynamics is essential, and the high energy deep
inelastic scattering experiment. We calculate the leading twist matrix
elements of the structure function at the low energy model scale within the
effective theory. Calculated structure functions are taken to the high
momentum scale with the help of the perturbative QCD, and compared with the
experimental data. Through a comparison of the model calculations with the
experiment, we discuss how the non-perturbative dynamics of the effective
theory is reflected in the deep inelastic phenomena. We first evaluate the
structure functions of the pseudoscalar mesons using the NJL model. The
resulting structure functions show reasonable agreement with experiments. We
then study the quark distribution functions of the nucleon using a covariant
quark–diquark model. We calculate three leading twist distribution
functions, the spin-independent
f1(x), the
longitudinal spin distribution
g1(x), and
the chiral-odd transversity spin distribution
h1(x). The
results for
f1(x) and
g1(x) turn
out to be consistent with available experiments because of the strong spin-0
diquark correlation.