Are the $J\mathrm{/}\psi$ and ${\chi }_{c}A$ Dependencies the Same?

It has been empirically observed that the dependence of $J\mathrm{/}\psi$ and ${\psi }^{\mathrm{\prime }}$ production on nuclear mass number $A$ is very similar. This has been postulated to be due to the predominance of color octet pre-resonant states in charmonium production and absorption. Two new experiments, NA60 at CERN and HERA-B at DESY, will measure the ${\chi }_c$ $A$ dependence for the first time. These measurements should shed new light on the charmonium production and absorption mechanisms.