Sudakov safety in perturbative QCD
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[su...
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| Format: | Article |
| Language: | English |
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American Physical Society
2015
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| Online Access: | http://hdl.handle.net/1721.1/97389 https://orcid.org/0000-0002-3181-4301 https://orcid.org/0000-0002-9675-7133 https://orcid.org/0000-0002-2406-8160 |
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| author | Marzani, Simone Thaler, Jesse Larkoski, Andrew |
| author2 | Massachusetts Institute of Technology. Center for Theoretical Physics |
| author_facet | Massachusetts Institute of Technology. Center for Theoretical Physics Marzani, Simone Thaler, Jesse Larkoski, Andrew |
| author_sort | Marzani, Simone |
| collection | MIT |
| description | 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]. |
| first_indexed | 2024-09-23T11:34:23Z |
| format | Article |
| id | mit-1721.1/97389 |
| institution | Massachusetts Institute of Technology |
| language | English |
| last_indexed | 2024-09-23T11:34:23Z |
| publishDate | 2015 |
| publisher | American Physical Society |
| record_format | dspace |
| spelling | mit-1721.1/973892022-09-27T20:23:53Z Sudakov safety in perturbative QCD Marzani, Simone Thaler, Jesse Larkoski, Andrew Massachusetts Institute of Technology. Center for Theoretical Physics Massachusetts Institute of Technology. Department of Physics Massachusetts Institute of Technology. Laboratory for Nuclear Science Larkoski, Andrew Marzani, Simone Thaler, Jesse 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]. United States. Dept. of Energy (Cooperative Research Agreement DE-FG02-05ER-41360) United States. Dept. of Energy (Early Career Research Program DE-FG02-11ER-41741) Alfred P. Sloan Foundation (Sloan Research Fellowship) National Science Foundation (U.S.) (Grant PHY-0969510) 2015-06-12T14:33:46Z 2015-06-12T14:33:46Z 2015-06 2015-02 2015-06-11T22:00:04Z Article http://purl.org/eprint/type/JournalArticle 1550-7998 1550-2368 http://hdl.handle.net/1721.1/97389 Larkoski, Andrew J., Simone Marzani, and Jesse Thaler. "Sudakov Safety in Perturbative QCD." Phys. Rev. D 91, 111501 (June 2015). © 2015 American Physical Society https://orcid.org/0000-0002-3181-4301 https://orcid.org/0000-0002-9675-7133 https://orcid.org/0000-0002-2406-8160 en http://dx.doi.org/10.1103/PhysRevD.91.111501 Physical Review D Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. American Physical Society application/pdf American Physical Society American Physical Society |
| spellingShingle | Marzani, Simone Thaler, Jesse Larkoski, Andrew Sudakov safety in perturbative QCD |
| title | Sudakov safety in perturbative QCD |
| title_full | Sudakov safety in perturbative QCD |
| title_fullStr | Sudakov safety in perturbative QCD |
| title_full_unstemmed | Sudakov safety in perturbative QCD |
| title_short | Sudakov safety in perturbative QCD |
| title_sort | sudakov safety in perturbative qcd |
| url | http://hdl.handle.net/1721.1/97389 https://orcid.org/0000-0002-3181-4301 https://orcid.org/0000-0002-9675-7133 https://orcid.org/0000-0002-2406-8160 |
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