J/ψ pair hadroproduction at next-to-leading order in nonrelativistic-QCD at CMS*

Abstract

Abstract We perform a complete study of pair hadroproduction at next-to-leading order (NLO) in the nonrelativstic-QCD (NRQCD) framework with the pair either in the or fock states. It is found that the channel contribution at NLO is essential. Our results indicate that for the CMS, the NRQCD predictions cannot describe the experimental data at all, and the total cross section predicted via NRQCD is smaller than the experimental data by an order of magnitude. Therefore, new mechanisms are needed to understand the CMS data for pair production.