  The competition between the staggered flux state, or the d-density wave
state, and the d-wave pairing state is analyzed in two-dimensional t-J model
based on the U(1) slave boson mean-field theory. Not only staggered flux of
spinon but also staggered flux of holon are considered. In this formalism, the
hopping order parameter of $physical$ electron is described by the product of
hopping order parameters of spinon and holon. The staggered flux amplitude of
electron is the difference of staggered flux amplitude of spinon and that of
holon. In $\pi$-flux phase of spinon, staggered fluxes of spinon and holon
cancel completely and staggered flux order of electron does not exist. However,
in staggered flux phase of spinon whose staggered flux amplitude is not $\pi$,
fluxes does not cancel completely and staggered flux amplitude of electron
remains. Thus, the phase transition between these two phases, $\pi$-flux phase
and staggered flux phase of spinon, becomes a second order transition in
$physical$ electron picture. The order parameter which characterizes this
transition is staggered flux order parameter of electron. A mean-field phase
diagram is shown. It is proved analytically that there is no coexisistence of
staggered flux and d-wave pairing. The temperature dependences of Fermi surface
and excitation gap at $(0,\pi)$ are shown. These behaviors are consistent with
angle-resolved photoemission spectroscopy (ARPES) experiments.
