  Parity-violating (pv) effects in inclusive hadron and jet productions in high
energy hadron-hadron collisions are analyzed. Such effects arise from the
interference between strong and weak amplitudes. This interference gives rise
to a nonzero value of the pv parameters $A_L$ and $P_L$, where $A_L$ measures
the difference in the inclusive cross sections of, for example, $p+p\ri {\rm
jet}+X$ ($X$=anything), with one of incident proton beams in a state of $\pm$
helicity, and $P_L$ denotes the longitudinal polarization of a high-energy
baryon (e.g., $\Lambda$) produced in $p+p\ri\Lambda+X$ with the initial proton
beams unpolarized. In the present paper, the single helicity asymmetry $A_L$ in
one-jet, two-jet and two-jet plus photon productions as well as in the
Drell-Yan process $p+p\ri\ell^+\ell^-+{\rm jet}+X$ is probed, and the
longitudinal polarization $P_L$ of the $\Lambda$ produced in unpolarized $pp$
collisions is studied. We conclude that the pv effects in high energy
proton-proton collisions are in general only sensitive to the spin dependent
valence quark distributions.
