  Recent advances in our understanding of the higher-wave quarkonia have
generated much interests in quarkonium physics. However most are devoted to
inclusive decays and productions. Experimental data of several two-body
exclusive decay channels of P-wave charmonia such as \pi \pi and p \bar p are
available and some have recently been re-measured by the BES collaboration. It
is not clear from the outset that color octet is needed for these exclusive
channels. Indeed only color singlet has been used in the past and reasonable
agreement with data was found. Contrary to these old results, we provide
theoretical arguments for the inclusion of color octet and perform explicit
calculations to back this up.
