Anatomy of the Higgs fits: A first guide to statistical treatments of the theoretical uncertainties
The studies of the Higgs boson couplings based on the recent and upcoming LHC data open up a new window on physics beyond the Standard Model. In this paper, we propose a statistical guide to the consistent treatment of the theoretical uncertainties entering the Higgs rate fits. Both the Bayesian and...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2016-04-01
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| Series: | Nuclear Physics B |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S0550321316000638 |
| _version_ | 1819111074779103232 |
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| author | Sylvain Fichet Grégory Moreau |
| author_facet | Sylvain Fichet Grégory Moreau |
| author_sort | Sylvain Fichet |
| collection | DOAJ |
| description | The studies of the Higgs boson couplings based on the recent and upcoming LHC data open up a new window on physics beyond the Standard Model. In this paper, we propose a statistical guide to the consistent treatment of the theoretical uncertainties entering the Higgs rate fits. Both the Bayesian and frequentist approaches are systematically analysed in a unified formalism. We present analytical expressions for the marginal likelihoods, useful to implement simultaneously the experimental and theoretical uncertainties. We review the various origins of the theoretical errors (QCD, EFT, PDF, production mode contamination…). All these individual uncertainties are thoroughly combined with the help of moment-based considerations. The theoretical correlations among Higgs detection channels appear to affect the location and size of the best-fit regions in the space of Higgs couplings. We discuss the recurrent question of the shape of the prior distributions for the individual theoretical errors and find that a nearly Gaussian prior arises from the error combinations. We also develop the bias approach, which is an alternative to marginalisation providing more conservative results. The statistical framework to apply the bias principle is introduced and two realisations of the bias are proposed. Finally, depending on the statistical treatment, the Standard Model prediction for the Higgs signal strengths is found to lie within either the 68% or 95% confidence level region obtained from the latest analyses of the 7 and 8 TeV LHC datasets. |
| first_indexed | 2024-12-22T03:51:50Z |
| format | Article |
| id | doaj.art-3a1f5803a59a441b8d40ae943638226b |
| institution | Directory Open Access Journal |
| issn | 0550-3213 1873-1562 |
| language | English |
| last_indexed | 2024-12-22T03:51:50Z |
| publishDate | 2016-04-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Nuclear Physics B |
| spelling | doaj.art-3a1f5803a59a441b8d40ae943638226b2022-12-21T18:39:59ZengElsevierNuclear Physics B0550-32131873-15622016-04-01905C39144610.1016/j.nuclphysb.2016.02.019Anatomy of the Higgs fits: A first guide to statistical treatments of the theoretical uncertaintiesSylvain Fichet0Grégory Moreau1ICTP South American Institute for Fundamental Research, Instituto de Fisica Teorica, Sao Paulo State University, BrazilLaboratoire de Physique Théorique, Bât. 210, CNRS, Université Paris-sud 11, F-91405 Orsay Cedex, FranceThe studies of the Higgs boson couplings based on the recent and upcoming LHC data open up a new window on physics beyond the Standard Model. In this paper, we propose a statistical guide to the consistent treatment of the theoretical uncertainties entering the Higgs rate fits. Both the Bayesian and frequentist approaches are systematically analysed in a unified formalism. We present analytical expressions for the marginal likelihoods, useful to implement simultaneously the experimental and theoretical uncertainties. We review the various origins of the theoretical errors (QCD, EFT, PDF, production mode contamination…). All these individual uncertainties are thoroughly combined with the help of moment-based considerations. The theoretical correlations among Higgs detection channels appear to affect the location and size of the best-fit regions in the space of Higgs couplings. We discuss the recurrent question of the shape of the prior distributions for the individual theoretical errors and find that a nearly Gaussian prior arises from the error combinations. We also develop the bias approach, which is an alternative to marginalisation providing more conservative results. The statistical framework to apply the bias principle is introduced and two realisations of the bias are proposed. Finally, depending on the statistical treatment, the Standard Model prediction for the Higgs signal strengths is found to lie within either the 68% or 95% confidence level region obtained from the latest analyses of the 7 and 8 TeV LHC datasets.http://www.sciencedirect.com/science/article/pii/S0550321316000638 |
| spellingShingle | Sylvain Fichet Grégory Moreau Anatomy of the Higgs fits: A first guide to statistical treatments of the theoretical uncertainties Nuclear Physics B |
| title | Anatomy of the Higgs fits: A first guide to statistical treatments of the theoretical uncertainties |
| title_full | Anatomy of the Higgs fits: A first guide to statistical treatments of the theoretical uncertainties |
| title_fullStr | Anatomy of the Higgs fits: A first guide to statistical treatments of the theoretical uncertainties |
| title_full_unstemmed | Anatomy of the Higgs fits: A first guide to statistical treatments of the theoretical uncertainties |
| title_short | Anatomy of the Higgs fits: A first guide to statistical treatments of the theoretical uncertainties |
| title_sort | anatomy of the higgs fits a first guide to statistical treatments of the theoretical uncertainties |
| url | http://www.sciencedirect.com/science/article/pii/S0550321316000638 |
| work_keys_str_mv | AT sylvainfichet anatomyofthehiggsfitsafirstguidetostatisticaltreatmentsofthetheoreticaluncertainties AT gregorymoreau anatomyofthehiggsfitsafirstguidetostatisticaltreatmentsofthetheoreticaluncertainties |