We perform a complete study on the J/Ο pair hadroproduction at
next-to-leading order (NLO) in the nonrelativstic-QCD (NRQCD) framework with
the pair of ccΛ either in 3S1[1]β or 1S0[8]β fock
state. It is found that the 1S0[8]β channel contribution at NLO is
essential. Our results indicate that for the CMS, the NRQCD predictions can not
describe the experimental data at all, and the total cross section predicted by
NRQCD is smaller than the experimental data by an order of magnitude. So new
mechanisms are needed to understand the CMS data for J/Ο pair production.Comment: 4 pages,4 figure