title: Heavy quarkonium production and polarization.
abstract: We present a perturbative QCD factorization formalism for the production of heavy quarkonia of large transverse momentum p(T) at collider energies, which includes both the leading-power (LP) and next-to-leading-power (NLP) contributions to the cross section in the m(Q)(2)/p(T)(2) expansion for heavy quark mass m(Q). We estimate fragmentation functions in the nonrelativistic QCD formalism and reproduce the bulk of the large enhancement found in explicit next-to-leading-order calculations in the color-singlet model. Heavy quarkonia produced from NLP channels prefer longitudinal polarization.
authors.affiliation: RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, New York 11973, USA.
authors.forename: Zhong-Bo
authors.initials: ZB
authors.lastname: Kang
authors.forename: Jian-Wei
authors.initials: JW
authors.lastname: Qiu
authors.forename: George
authors.initials: G
authors.lastname: Sterman