We compute the relativistic corrections to the color-singlet contribution to gluon fragmentation into a J/ψ at relative order ν4, making use of the nonrelativistic QCD (NRQCD) factorization approach. The corresponding full-QCD process exhibits infrared divergences that manifest themselves as single and double poles in ε in 4-2ε dimensions. We isolate the infrared-divergent contributions and treat them analytically. In the matching of full QCD to NRQCD, the pole contributions are absorbed into long-distance NRQCD matrix elements. The renormalizations of the ultraviolet divergences of the long-distance NRQCD matrix elements involve Born and one-loop single-pole counterterm contributions and Born double-pole counterterm contributions. While the order-ν4 contribution enhances the J/ψ hadroproduction rate for the color-singlet channel substantially, this contribution is not important numerically in comparison with the color-octet contributions. We also find that the 3PJ color-octet channel in the gluon fragmentation function contributes to J/ψ hadroproduction significantly in comparison with the complete contribution of next-to-leading order in αs in that channel.
|Journal||Proceedings of Science|
|Publication status||Published - 2012|
|Event||10th Conference on Quark Confinement and the Hadron Spectrum, Confinement 2012 - Munich, Germany|
Duration: 2012 Oct 8 → 2012 Oct 12
ASJC Scopus subject areas