Color octet contribution in exclusive P-wave charmonium decay into octet and decuplet baryons

Abstract. In the last years, the need for the color octet state in inclusive P-wave charmonium decay has been firmly established. However, the implications of this in the corresponding exclusive reactions have not been fully recognized. We argue for the necessity of the color octet in P- and higher-wave quarkonium decay. Using a set of phenomenologically constructed baryon wave functions, we consider the $\chi_J$ decay into an octet and decuplet baryon–antibaryon pair. By doing so, we subject the wave functions to a test of applicability. We show that the color singlet component alone is insufficient to account for the experimental measurements, and only by including the color octet contribution can the partial theoretical decay widths be brought into the range of the data. By the present and earlier applications of the set of wave functions, these show themselves to be reasonable model wave functions at around the scale $Q^2 \sim 10$–20 GeV$^2$.