Flavor fragmentation function factorization
Abstract A definition of partonic jet flavor that is both theoretically well-defined and experimentally robust would have profound implications for measurements and predictions especially for heavy flavor applications. Recently, a definition of jet flavor was introduced as the net flavor flowing alo...
| Main Authors: | , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
SpringerOpen
2024-01-01
|
| Series: | Journal of High Energy Physics |
| Subjects: | |
| Online Access: | https://doi.org/10.1007/JHEP01(2024)119 |
| _version_ | 1797341352011235328 |
|---|---|
| author | Andrew J. Larkoski Duff Neill |
| author_facet | Andrew J. Larkoski Duff Neill |
| author_sort | Andrew J. Larkoski |
| collection | DOAJ |
| description | Abstract A definition of partonic jet flavor that is both theoretically well-defined and experimentally robust would have profound implications for measurements and predictions especially for heavy flavor applications. Recently, a definition of jet flavor was introduced as the net flavor flowing along the direction of the Winner-Take-All axis of a jet which is soft safe to all orders, but not collinear safe. Here, we exploit the lack of collinear safety and propose a factorization theorem of perturbative flavor fragmentation functions that resum collinear divergences and describe the evolution of flavor from the short distance of jet production to the long distance at which hadronization occurs. Collinear flavor evolution is governed by a small modification of the DGLAP equations. We present a detailed all-orders analysis and identify exact relations that must hold amongst the various anomalous dimensions by probability conservation and the existence of fixed points of the renormalization group flow. We explicitly validate the factorization theorem at one-loop order, and demonstrate its consistency at two loops in particular flavor channels. Starting at two-loops, constraints on phase space imposed by flavor measurements potentially allow for non-trivial soft contributions, but we demonstrate that they are scaleless and so explicitly vanish, ensuring that soft particles are summed inclusively and all divergences are exclusively collinear in nature. This factorization theorem opens the door to precision calculations with identified flavor in the infrared. |
| first_indexed | 2024-03-08T10:16:46Z |
| format | Article |
| id | doaj.art-6da46ca9e7ae425c96c34bda927713e5 |
| institution | Directory Open Access Journal |
| issn | 1029-8479 |
| language | English |
| last_indexed | 2024-03-08T10:16:46Z |
| publishDate | 2024-01-01 |
| publisher | SpringerOpen |
| record_format | Article |
| series | Journal of High Energy Physics |
| spelling | doaj.art-6da46ca9e7ae425c96c34bda927713e52024-01-28T12:24:39ZengSpringerOpenJournal of High Energy Physics1029-84792024-01-012024114610.1007/JHEP01(2024)119Flavor fragmentation function factorizationAndrew J. Larkoski0Duff Neill1Department of Physics and Astronomy, University of CaliforniaTheoretical Division, Los Alamos National LaboratoryAbstract A definition of partonic jet flavor that is both theoretically well-defined and experimentally robust would have profound implications for measurements and predictions especially for heavy flavor applications. Recently, a definition of jet flavor was introduced as the net flavor flowing along the direction of the Winner-Take-All axis of a jet which is soft safe to all orders, but not collinear safe. Here, we exploit the lack of collinear safety and propose a factorization theorem of perturbative flavor fragmentation functions that resum collinear divergences and describe the evolution of flavor from the short distance of jet production to the long distance at which hadronization occurs. Collinear flavor evolution is governed by a small modification of the DGLAP equations. We present a detailed all-orders analysis and identify exact relations that must hold amongst the various anomalous dimensions by probability conservation and the existence of fixed points of the renormalization group flow. We explicitly validate the factorization theorem at one-loop order, and demonstrate its consistency at two loops in particular flavor channels. Starting at two-loops, constraints on phase space imposed by flavor measurements potentially allow for non-trivial soft contributions, but we demonstrate that they are scaleless and so explicitly vanish, ensuring that soft particles are summed inclusively and all divergences are exclusively collinear in nature. This factorization theorem opens the door to precision calculations with identified flavor in the infrared.https://doi.org/10.1007/JHEP01(2024)119FactorizationRenormalization GroupHigher-Order Perturbative CalculationsJets and Jet SubstructureFlavour Symmetries |
| spellingShingle | Andrew J. Larkoski Duff Neill Flavor fragmentation function factorization Journal of High Energy Physics Factorization Renormalization Group Higher-Order Perturbative Calculations Jets and Jet Substructure Flavour Symmetries |
| title | Flavor fragmentation function factorization |
| title_full | Flavor fragmentation function factorization |
| title_fullStr | Flavor fragmentation function factorization |
| title_full_unstemmed | Flavor fragmentation function factorization |
| title_short | Flavor fragmentation function factorization |
| title_sort | flavor fragmentation function factorization |
| topic | Factorization Renormalization Group Higher-Order Perturbative Calculations Jets and Jet Substructure Flavour Symmetries |
| url | https://doi.org/10.1007/JHEP01(2024)119 |
| work_keys_str_mv | AT andrewjlarkoski flavorfragmentationfunctionfactorization AT duffneill flavorfragmentationfunctionfactorization |