A parton shower consistent with parton densities at LO and NLO: Pdf2Isr.
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| Title: | A parton shower consistent with parton densities at LO and NLO: Pdf2Isr. |
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| Authors: | Jung, H.1,2 (AUTHOR) hannes.jung@desy.de, Lönnblad, L.3 (AUTHOR) leif.lonnblad@fysik.lu.se, Mendizabal, M.1 (AUTHOR) mikel.mendizabal.morentin@desy.de, Taheri Monfared, Sara1 (AUTHOR) sara.taheri.monfared@desy.de |
| Source: | European Physical Journal C -- Particles & Fields. Aug2025, Vol. 85 Issue 8, p1-17. 17p. |
| Subjects: | Partons, Momentum distributions, Simulation software |
| Abstract: | We present a method for obtaining an initial-state parton shower model where the (backward) evolution fully consistent with the (forward) evolution of the collinear parton density used. As a proof-of-concept we use parton densities obtained with the parton branching (PB) approach, and modify the default initial-state shower in Pythia8 with this method to be consistent with them. PB is ideally suited for checking the validity of our method since, in addition to producing collinear parton densities, it also produces the corresponding transverse-dependent (TMD) ones, and these can then be directly compared to the transverse momentum distribution obtained from the parton shower. We show that TMD distributions which we in this way obtain from our modified Pythia8 shower using leading order (LO) parton densities and splitting functions are fully consistent with the corresponding leading order TMD densities. At next-to-leading order (NLO) it is not possible to achieve the same consistency using the built-in LO splitting functions in the shower, but we show that by introducing NLO splitting functions using a reweighting procedure, we can achieve consistency also at NLO. The method presented here, which we have named Pdf2Isr, can be easily extended to any collinear parton densities, as long as the exact conditions for the evolution are known. With the Pdf2Isr method we obtain an initial-state parton shower which in principle has no free parameters, and is fully consistent with collinear parton densities at LO and NLO. [ABSTRACT FROM AUTHOR] |
| Copyright of European Physical Journal C -- Particles & Fields is the property of Springer Nature and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Engineering Source |
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| Header | DbId: egs DbLabel: Engineering Source An: 187993638 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: A parton shower consistent with parton densities at LO and NLO: Pdf2Isr. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Jung%2C+H%2E%22">Jung, H.</searchLink><relatesTo>1,2</relatesTo> (AUTHOR)<i> hannes.jung@desy.de</i><br /><searchLink fieldCode="AR" term="%22Lönnblad%2C+L%2E%22">Lönnblad, L.</searchLink><relatesTo>3</relatesTo> (AUTHOR)<i> leif.lonnblad@fysik.lu.se</i><br /><searchLink fieldCode="AR" term="%22Mendizabal%2C+M%2E%22">Mendizabal, M.</searchLink><relatesTo>1</relatesTo> (AUTHOR)<i> mikel.mendizabal.morentin@desy.de</i><br /><searchLink fieldCode="AR" term="%22Taheri+Monfared%2C+Sara%22">Taheri Monfared, Sara</searchLink><relatesTo>1</relatesTo> (AUTHOR)<i> sara.taheri.monfared@desy.de</i> – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22European+Physical+Journal+C+--+Particles+%26+Fields%22">European Physical Journal C -- Particles & Fields</searchLink>. Aug2025, Vol. 85 Issue 8, p1-17. 17p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Partons%22">Partons</searchLink><br /><searchLink fieldCode="DE" term="%22Momentum+distributions%22">Momentum distributions</searchLink><br /><searchLink fieldCode="DE" term="%22Simulation+software%22">Simulation software</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: We present a method for obtaining an initial-state parton shower model where the (backward) evolution fully consistent with the (forward) evolution of the collinear parton density used. As a proof-of-concept we use parton densities obtained with the parton branching (PB) approach, and modify the default initial-state shower in Pythia8 with this method to be consistent with them. PB is ideally suited for checking the validity of our method since, in addition to producing collinear parton densities, it also produces the corresponding transverse-dependent (TMD) ones, and these can then be directly compared to the transverse momentum distribution obtained from the parton shower. We show that TMD distributions which we in this way obtain from our modified Pythia8 shower using leading order (LO) parton densities and splitting functions are fully consistent with the corresponding leading order TMD densities. At next-to-leading order (NLO) it is not possible to achieve the same consistency using the built-in LO splitting functions in the shower, but we show that by introducing NLO splitting functions using a reweighting procedure, we can achieve consistency also at NLO. The method presented here, which we have named Pdf2Isr, can be easily extended to any collinear parton densities, as long as the exact conditions for the evolution are known. With the Pdf2Isr method we obtain an initial-state parton shower which in principle has no free parameters, and is fully consistent with collinear parton densities at LO and NLO. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of European Physical Journal C -- Particles & Fields is the property of Springer Nature and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1140/epjc/s10052-025-14595-y Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 17 StartPage: 1 Subjects: – SubjectFull: Partons Type: general – SubjectFull: Momentum distributions Type: general – SubjectFull: Simulation software Type: general Titles: – TitleFull: A parton shower consistent with parton densities at LO and NLO: Pdf2Isr. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Jung, H. – PersonEntity: Name: NameFull: Lönnblad, L. – PersonEntity: Name: NameFull: Mendizabal, M. – PersonEntity: Name: NameFull: Taheri Monfared, Sara IsPartOfRelationships: – BibEntity: Dates: – D: 01 M: 08 Text: Aug2025 Type: published Y: 2025 Identifiers: – Type: issn-print Value: 14346044 Numbering: – Type: volume Value: 85 – Type: issue Value: 8 Titles: – TitleFull: European Physical Journal C -- Particles & Fields Type: main |
| ResultId | 1 |
