Determining the nonperturbative Collins-Soper kernel from lattice QCD
At small transverse momentum q[subscript T], transverse-momentum dependent parton distribution functions (TMDPDFs) arise as genuinely nonperturbative objects that describe Drell-Yan like processes in hadron collisions as well as semi-inclusive deep-inelastic scattering. TMDPDFs naturally depend on t...
| Main Authors: | , , |
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| Other Authors: | |
| Format: | Article |
| Language: | English |
| Published: |
American Physical Society
2019
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| Online Access: | http://hdl.handle.net/1721.1/120589 https://orcid.org/0000-0003-0555-0688 https://orcid.org/0000-0003-0248-0979 |
| Summary: | At small transverse momentum q[subscript T], transverse-momentum dependent parton distribution functions (TMDPDFs) arise as genuinely nonperturbative objects that describe Drell-Yan like processes in hadron collisions as well as semi-inclusive deep-inelastic scattering. TMDPDFs naturally depend on the hadron momentum, and the associated evolution is determined by the Collins-Soper equation. For q[subscript T] ∼ Λ[subscript QCD] the corresponding evolution kernel (or anomalous dimension) is nonperturbative and must be determined as an independent ingredient in order to relate TMDPDFs at different scales. We propose a method to extract this kernel using lattice QCD and the large-momentum effective theory, where the physical TMD correlation involving light-like paths is approximated by a quasi-TMDPDF, defined using equal-time correlation functions with a large-momentum hadron state. The kernel is determined from a ratio of quasi-TMDPDFs extracted at different hadron momenta. |
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