\chi_{cJ} polarizations at the Fermilab Tevatron

Abstract

We propose the measurement of ${\chi }_{cJ}$ polarizations at high energy hadron colliders to study heavy quarkonium production mechanism. We find that the color-singlet model in the $k_t$ factorization approach predicts very different behavior for ${\chi }_{cJ}$ polarizations at the Fermilab Tevatron compared with the NRQCD predictions in the collinear parton model. In the color-singlet $k_t$ factorization approach, for both ${\chi }_{c1}$ and ${\chi }_{c2}$ productions, the helicity $h=0$ states dominate over other helicity states at large $p_T$. These properties are very useful in distinguishing between the two production mechanisms which are related to the interesting issue of $J\psi$ and ${\psi }^{\prime }$ polarizations, and may provide a crucial test for the $k_t$ factorization approach.

Comments: PLB in press