  Implication of our recent proposal [J. Phys. Soc. Jpn. 65 (1996) 687] to
treat large-amplitude gauge-field fluctuations around the slave-boson
mean-field theory for the t-J model has been explored in detail. By attaching
gauge flux to spinons and holons and then treating them as free g-on's which
respect the time-reversal symmetry, the optimum exclusion (g) and exchange (\a)
statistics have been determined in the plane of doping rate and temperature.
Two different relations between \a and g have been investigated, namely g=|\a|
(Case1) and g=|\a|(2-|\a|) (Case2). The results indicate that slave fermion is
favored at low doping while slave boson at high doping. For two dimension, in
Case1 intermediate statistics are found in between, while in Case2 no
intermediate statistics are found. The consequences of varying the
dimensionality and strength of J have been studied also. The latter has no
qualitative effect for both cases, while the former has a profound effect in
Case1.
