Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Polarization as a Probe to the Production Mechanisms of Charmonium in
  $\pi N$ Collisions   Measurements of the polarization of $\jp$ produced in pion-nucleus collisions
are in disagreement with leading twist QCD prediction where $\jp$ is observed
to have negligible polarization whereas theory predicts substantial
polarization. We argue that this discrepancy cannot be due to poorly known
structure functions nor the relative production rates of $\jp$ and $\chi_J$.
The disagreement between theory and experiment suggests important higher twist
corrections, as has earlier been surmised from the anomalous non-factorized
nuclear $A$-dependence of the $\jp$ cross section.

27
The categories of this paper are: comp-gas
9
The categories of this paper are: nlin
15
The categories of this paper are: nucl-ex
20
The categories of this paper are: acc-phys
13
The categories of this paper are: quant-ph
33
The categories of this paper are: plasm-ph
4
The categories of this paper are: cond-mat
3
The categories of this paper are: physics
28
The categories of this paper are: alg-geom
17
The categories of this paper are: q-fin
7
The categories of this paper are: hep-th
10
The categories of this paper are: q-bio
2
The categories of this paper are: math
26
The categories of this paper are: bayes-an
19
The categories of this paper are: eess
25
The categories of this paper are: patt-sol