Regularising experimental correlations in LHC data: theory and application to a global analysis of parton distributions
Abstract We show how an inaccurate determination of experimental uncertainty correlations in high-precision LHC measurements may undermine the reliability of the associated $$\chi ^2$$ χ 2 . We formulate the problem rigorously, and devise a regularisation procedure that increases the stability of th...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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SpringerOpen
2022-10-01
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| Series: | European Physical Journal C: Particles and Fields |
| Online Access: | https://doi.org/10.1140/epjc/s10052-022-10932-7 |
| _version_ | 1828731759747923968 |
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| author | Zahari Kassabov Emanuele R. Nocera Michael Wilson |
| author_facet | Zahari Kassabov Emanuele R. Nocera Michael Wilson |
| author_sort | Zahari Kassabov |
| collection | DOAJ |
| description | Abstract We show how an inaccurate determination of experimental uncertainty correlations in high-precision LHC measurements may undermine the reliability of the associated $$\chi ^2$$ χ 2 . We formulate the problem rigorously, and devise a regularisation procedure that increases the stability of the $$\chi ^2$$ χ 2 by altering the covariance matrix of the measurement as little as possible. We apply the procedure to the NNPDF4.0 global analysis of parton distribution functions that utilises a large amount of LHC measurements. We find that the regularised $$\chi ^2$$ χ 2 of the NNPDF4.0 determination is lowered by about $$3\sigma $$ 3 σ , without significantly altering the resulting PDFs upon refitting. |
| first_indexed | 2024-04-12T17:51:05Z |
| format | Article |
| id | doaj.art-867b9bf9fa2f4b8e834529411370b2ad |
| institution | Directory Open Access Journal |
| issn | 1434-6052 |
| language | English |
| last_indexed | 2024-04-12T17:51:05Z |
| publishDate | 2022-10-01 |
| publisher | SpringerOpen |
| record_format | Article |
| series | European Physical Journal C: Particles and Fields |
| spelling | doaj.art-867b9bf9fa2f4b8e834529411370b2ad2022-12-22T03:22:30ZengSpringerOpenEuropean Physical Journal C: Particles and Fields1434-60522022-10-01821012010.1140/epjc/s10052-022-10932-7Regularising experimental correlations in LHC data: theory and application to a global analysis of parton distributionsZahari Kassabov0Emanuele R. Nocera1Michael Wilson2DAMTP, University of CambridgeThe Higgs Centre for Theoretical Physics, University of Edinburgh JCMBThe Higgs Centre for Theoretical Physics, University of Edinburgh JCMBAbstract We show how an inaccurate determination of experimental uncertainty correlations in high-precision LHC measurements may undermine the reliability of the associated $$\chi ^2$$ χ 2 . We formulate the problem rigorously, and devise a regularisation procedure that increases the stability of the $$\chi ^2$$ χ 2 by altering the covariance matrix of the measurement as little as possible. We apply the procedure to the NNPDF4.0 global analysis of parton distribution functions that utilises a large amount of LHC measurements. We find that the regularised $$\chi ^2$$ χ 2 of the NNPDF4.0 determination is lowered by about $$3\sigma $$ 3 σ , without significantly altering the resulting PDFs upon refitting.https://doi.org/10.1140/epjc/s10052-022-10932-7 |
| spellingShingle | Zahari Kassabov Emanuele R. Nocera Michael Wilson Regularising experimental correlations in LHC data: theory and application to a global analysis of parton distributions European Physical Journal C: Particles and Fields |
| title | Regularising experimental correlations in LHC data: theory and application to a global analysis of parton distributions |
| title_full | Regularising experimental correlations in LHC data: theory and application to a global analysis of parton distributions |
| title_fullStr | Regularising experimental correlations in LHC data: theory and application to a global analysis of parton distributions |
| title_full_unstemmed | Regularising experimental correlations in LHC data: theory and application to a global analysis of parton distributions |
| title_short | Regularising experimental correlations in LHC data: theory and application to a global analysis of parton distributions |
| title_sort | regularising experimental correlations in lhc data theory and application to a global analysis of parton distributions |
| url | https://doi.org/10.1140/epjc/s10052-022-10932-7 |
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