Unified treatment of the QCD evolution of all (un-)polarized transverse momentum dependent functions: Collins function as a study case



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Echevarria, Miguel G. and Idilbi, Ahmad and Scimemi, Ignazio (2014) Unified treatment of the QCD evolution of all (un-)polarized transverse momentum dependent functions: Collins function as a study case. Physical review D, 90 (1). ISSN 1550-7998

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Official URL: http://dx.doi.org/10.1103/PhysRevD.90.014003


By considering semi-inclusive deep-inelastic scattering and the (complementary) qT-spectrum for Drell-Yan lepton pair production we derive the QCD evolution for all the leading-twist transverse momentum dependent distribution and fragmentation functions. We argue that all of those functions evolve with Q2 following a single evolution kernel. This kernel is independent of the underlying kinematics and it is also spin independent. Those features hold, in impact parameter space, to all values of bT. The evolution kernel presented has all of its large logarithms resummed up to next-to-next-to leading logarithmic accuracy, which is the highest possible accuracy given the existing perturbative calculations. As a study case we apply this kernel to investigate the evolution of the Collins function, one of the ingredients that have recently attracted much attention within the phenomenological studies of spin asymmetries. Our analysis can be readily implemented to revisit previously obtained fits that involve data at different scales for other spin-dependent functions. Such improved fits are important to get better predictions—with the correct evolution kernel—for certain upcoming experiments aiming to measure the Sivers function, Collins function, transversity, and other spin-dependent functions as well.

Item Type:Article
Additional Information:

© 2014 American Physical Society. We thank A. Vladimirov for useful comments. I. S. is supported by the Spanish MEC, Grant No. FPA2011-27853-CO2-02. M.G.E. is supported by the “Stichting voor Fundamenteel Onderzoek der Materie” (FOM), which is financially supported by the “Nederlandse Organisatie voor Wetenschappelijk Onderzoek” (NWO). A.I. is supported by the U.S. Department of Energy under Award No. DESC0008745.

Uncontrolled Keywords:Drell-Yan; Distributions.
Subjects:Sciences > Physics > Physics-Mathematical models
Sciences > Physics > Mathematical physics
ID Code:29425
Deposited On:10 Apr 2015 08:41
Last Modified:10 Dec 2018 15:09

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