chi(cJ) polarizations at the Fermilab Tevatron

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 differ ent behavior for chi (cJ) polarizations at the Fermilab Tevatron compared w ith the NRQCD predictions in the collinear parton model. In the color-singl et 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 produ ction mechanisms which are related to the interesting issue of J psi and ps i' polarizations, and may provide a crucial test for the k(t) factorization approach. (C) 2001 Elsevier Science B.V. All rights reserved.