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arXiv · 1401.0923

Heavy Quarkonium Production at Collider Energies: Factorization and Evolution

Zhong-Bo Kang·Yan-Qing Ma·Jian-Wei Qiu·George Sterman
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Abstract

We present a factorization formalism for inclusive production of heavy quarkonia of large transverse momentum, $p_T$ at collider energies, including both leading power (LP) and next-to-leading power (NLP) behavior in $p_T$. We demonstrate that both LP and NLP contributions can be factorized in terms of perturbatively calculable short-distance partonic coefficient functions and universal non-perturbative fragmentation functions, and derive the evolution equations that are implied by the factorization. We identify projection operators for all channels of the factorized LP and NLP infrared safe short-distance partonic hard parts, and corresponding operator definitions of fragmentation functions. For the NLP, we focus on the contributions involving the production of a heavy quark pair, a necessary condition for producing a heavy quarkonium. We evaluate the first non-trivial order of evolution kernels for all relevant fragmentation functions, and discuss the role of NLP contributions.

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Zhong-Bo Kang, Yan-Qing Ma, Jian-Wei Qiu, George Sterman. 2014-11-10. Heavy Quarkonium Production at Collider Energies: Factorization and Evolution. https://doi.org/10.1103/physrevd.90.034006

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