Does parity violation just mean particles are chiral? Wu's experiment shows that the mirror image of a system doesn't necessarily act the same as the original system. But the experiment only mirrors the position of every particle, not the particles themselves!
Wouldn't the logical conclusion be that quarks are not just points, but rather more complex structures that have a chirality, and that when we mirror the system, we should also be mirroring the quarks themselves, rather than just their position. The 60% preference towards one end would then mean that 60% of quarks around us are left-handed, and 40% are right-handed.
 A: Generally, a parity violation is observed when a scalar quantity, such as an interaction rate or an energy, is found to depend on pseudoscalar quantity.  For example, the "polar" vectors describing position $\vec r$ or momentum $\vec p$ change sign under reflection, but angular momentum $\vec L=\vec r\times\vec p$ does not (or changes sign twice, if you prefer).  In the Wu et al. experiment, the reaction rate (a scalar) depends on the scalar product between the nuclear spin $\vec\sigma$ and the electron momentum $\vec p$.  But the scalar product $\vec\sigma\cdot\vec p$ between an "axial vector" and a polar vector will change sign under reflection:  the reaction rate is a mixture of scalar and "pseudoscalar."  That's the parity violation.
Note that the product $\vec\sigma\cdot\vec p$ for a single particle is its helicity, not its chirality; the two are correlated only in the high-momentum limit.  A massive particle in its rest frame is equal parts left- and right-handed chirality, regardless of its spin polarization.  And decays (as in Wu et al.) must be analyzed in the rest frame of the decaying particle.  (If you object that cobalt is a big nucleus, look instead at decays of free neutrons. Or muons, even, which have no substructure at all.  The Lederman et al. discovery of parity violation in muon decay is the paper following Wu et al. in Physical Review.)
The explanation in the Standard Model for parity violation is that the charged weak current, whose vector boson is the $W^\pm$, interacts with left-chiral particles and with right-chiral antiparticles, but not vice-versa.  That explains parity violation in rest-frame decays, while a boost-dependent excess of one chirality would not.
