Sudakov safety in perturbative QCD
Name
PhysRevD.91.111501.pdf
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276.84 KB
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Adobe PDF
Checksum (MD5)
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Author(s)
Marzani, Simone
Thaler, Jesse
Larkoski, Andrew
Date Issued
June 2015
Journal
Physical Review D
Publisher
American Physical Society
Citation
Larkoski, Andrew J., Simone Marzani, and Jesse Thaler. "Sudakov Safety in Perturbative QCD." Phys. Rev. D 91, 111501 (June 2015). © 2015 American Physical Society
Version
Final published version
Abstract
Traditional calculations in perturbative quantum chromodynamics (pQCD) are based on an order-by-order expansion in the strong coupling α[subscript s]. Observables that are calculable in this way are known as “safe.” Recently, a class of unsafe observables was discovered that do not have a valid α[subscript s] expansion but are nevertheless calculable in pQCD using all-orders resummation. These observables are called “Sudakov safe” since singularities at each α[subscript s] order are regulated by an all-orders Sudakov form factor. In this paper, we give a concrete definition of Sudakov safety based on conditional probability distributions, and we study a one-parameter family of momentum sharing observables that interpolate between the safe and unsafe regimes. The boundary between these regimes is particularly interesting, as the resulting distribution can be understood as the ultraviolet fixed point of a generalized fragmentation function, yielding a leading behavior that is independent of α[subscript s].
MIT Department
Massachusetts Institute of Technology. Center for Theoretical Physics
Massachusetts Institute of Technology. Department of Physics
Massachusetts Institute of Technology. Laboratory for Nuclear Science
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DOI of Published Version
https://doi.org/10.1103/PhysRevD.91.111501
