15 research outputs found

    Signal region combination with full and simplified likelihoods in MadAnalysis 5

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    The statistical combination of disjoint signal regions in reinterpretation studies uses more of the data of an analysis and gives more robust results than the single signal region approach. We present the implementation and usage of signal region combination in MadAnalysis 5 through two methods: an interface to the pyhf package making use of statistical models in JSON-serialised format provided by the ATLAS collaboration, and a simplified likelihood calculation making use of covariance matrices provided by the CMS collaboration. The gain in physics reach is demonstrated 1.) by comparison with official mass limits for 4 ATLAS and 5 CMS analyses from the Public Analysis Database of MadAnalysis 5 for which signal region combination is currently available, and 2.) by a case study for an MSSM scenario in which both stops and sbottoms can be produced and have a variety of decays into charginos and neutralinos.Comment: 29 pages, 12 figures; matches journal versio

    Reinterpretation of LHC Results for New Physics: Status and recommendations after Run 2

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    We report on the status of efforts to improve the reinterpretation of searches and measurements at the LHC in terms of models for new physics, in the context of the LHC Reinterpretation Forum. We detail current experimental offerings in direct searches for new particles, measurements, technical implementations and Open Data, and provide a set of recommendations for further improving the presentation of LHC results in order to better enable reinterpretation in the future. We also provide a brief description of existing software reinterpretation frameworks and recent global analyses of new physics that make use of the current data

    Au-delà du modèle standard : phénoménologie de matière noire exotique et contraintes du LHC

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    The Standard Model (SM) of particle physics is one of the most successful theories in science. Indeed, numerous SM prediction have been observed to be consistent with experimental measurements. However, some caveats hint for the incompleteness of the SM and push physicists to search for new physics. The ATLAS and CMS collaborations are carrying out an extensive and exciting physics programme at the LHC. Searches for new physics constitute a relevant part of this program. Simplified models are used to characterize the potential new physics signal. Reinterpreting the LHC results in more realistic scenarios than the simplified models is crucial in order to use the most of the physics sensitivity of the data.The work of this thesis focused on two aspects of reinterpretation, the improvement of reinterpretation tools and the phenomenology of beyond the Standard Model (BSM). The statistical combination of signal regions (SRs) allows to use more of the physics sensitivity of the experimental data in public tools. This thesis participated in the implementation of this feature in MadAnalysis5 and SModelS. Part of the focus was also given to phenomenological studies in order to demonstrates the impact of SR combination. Explaining the nature of dark matter (DM) is another area where the SM fails. Although many hypothetical particles with different properties are good DM candidates, the way they are produced in the early Universe can be classified into a few main mechanisms. The standard WIMP picture is based on the freeze-out mechanism, which is based on several assumptions that are valid in general cases. However, these assumptions can be broke for some scenarios, leading to exceptions to the standard WIMP picture. The DM portion of this thesis focused on a recently proposed mechanism, which is the conversion-driven freeze-out mechanism.Le Modèle Standard (MS) de la physique des particules est l'une des théories les plus réussies de la science. En effet, de nombreuses prédictions du MS se sont révélées cohérentes avec les mesures expérimentales. Cependant, certaines exceptions laissent entrevoir l'incomplétude du MS et poussent les physiciens à rechercher une nouvelle physique. Les collaborations ATLAS et CMS mènent un vaste et passionnant programme de physique au LHC. La recherche de nouvelle physique constitue une partie importante de ce programme. Des modèles simplifiés sont utilisés pour caractériser les potentiels signaux de nouvelle physique. La réinterprétation des résultats du LHC dans des scénarios plus réalistes que les modèles simplifiés est cruciale afin d'utiliser au mieux le potentiel des données expérimentales. Le travail de cette thèse s'est concentré sur deux aspects de la réinterprétation, l'amélioration des outils de réinterprétation et la phénoménologie au-delà du Modèle Standard (BSM). La combinaison statistique des SRs permet d'utiliser davantage la sensibilité physique des données expérimentales dans les outils publics. Cette thèse a participé à l'implémentation de cette fonctionnalité dans MadAnalysis5 et SModelS. Une partie de l'attention a également été accordée aux études phénoménologiques afin de démontrer l'impact de la combinaison de SRs. Expliquer la nature de la matière noire est un autre domaine où le MS échoue. Bien que de nombreuses particules hypothétiques ayant des propriétés différentes soient de bons candidats pour la matière noire, la façon dont elles sont produites dans l'Univers primitif peut être classée en quelques mécanismes principaux. Le paradigme standard des WIMPs est basé sur le mécanisme de "freeze-out'', qui repose sur plusieurs hypothèses valables dans les cas les plus généraux. La partie matière noire de cette thèse s'est concentrée sur un mécanisme récemment proposé, qui est le mécanisme de freeze-out par conversion, ou "coscattering''

    Au-delà du modèle standard : phénoménologie de matière noire exotique et contraintes du LHC

    No full text
    The Standard Model (SM) of particle physics is one of the most successful theories in science. Indeed, numerous SM prediction have been observed to be consistent with experimental measurements. However, some caveats hint for the incompleteness of the SM and push physicists to search for new physics. The ATLAS and CMS collaborations are carrying out an extensive and exciting physics programme at the LHC. Searches for new physics constitute a relevant part of this program. Simplified models are used to characterize the potential new physics signal. Reinterpreting the LHC results in more realistic scenarios than the simplified models is crucial in order to use the most of the physics sensitivity of the data.The work of this thesis focused on two aspects of reinterpretation, the improvement of reinterpretation tools and the phenomenology of beyond the Standard Model (BSM). The statistical combination of signal regions (SRs) allows to use more of the physics sensitivity of the experimental data in public tools. This thesis participated in the implementation of this feature in MadAnalysis5 and SModelS. Part of the focus was also given to phenomenological studies in order to demonstrates the impact of SR combination. Explaining the nature of dark matter (DM) is another area where the SM fails. Although many hypothetical particles with different properties are good DM candidates, the way they are produced in the early Universe can be classified into a few main mechanisms. The standard WIMP picture is based on the freeze-out mechanism, which is based on several assumptions that are valid in general cases. However, these assumptions can be broke for some scenarios, leading to exceptions to the standard WIMP picture. The DM portion of this thesis focused on a recently proposed mechanism, which is the conversion-driven freeze-out mechanism.Le Modèle Standard (MS) de la physique des particules est l'une des théories les plus réussies de la science. En effet, de nombreuses prédictions du MS se sont révélées cohérentes avec les mesures expérimentales. Cependant, certaines exceptions laissent entrevoir l'incomplétude du MS et poussent les physiciens à rechercher une nouvelle physique. Les collaborations ATLAS et CMS mènent un vaste et passionnant programme de physique au LHC. La recherche de nouvelle physique constitue une partie importante de ce programme. Des modèles simplifiés sont utilisés pour caractériser les potentiels signaux de nouvelle physique. La réinterprétation des résultats du LHC dans des scénarios plus réalistes que les modèles simplifiés est cruciale afin d'utiliser au mieux le potentiel des données expérimentales. Le travail de cette thèse s'est concentré sur deux aspects de la réinterprétation, l'amélioration des outils de réinterprétation et la phénoménologie au-delà du Modèle Standard (BSM). La combinaison statistique des SRs permet d'utiliser davantage la sensibilité physique des données expérimentales dans les outils publics. Cette thèse a participé à l'implémentation de cette fonctionnalité dans MadAnalysis5 et SModelS. Une partie de l'attention a également été accordée aux études phénoménologiques afin de démontrer l'impact de la combinaison de SRs. Expliquer la nature de la matière noire est un autre domaine où le MS échoue. Bien que de nombreuses particules hypothétiques ayant des propriétés différentes soient de bons candidats pour la matière noire, la façon dont elles sont produites dans l'Univers primitif peut être classée en quelques mécanismes principaux. Le paradigme standard des WIMPs est basé sur le mécanisme de "freeze-out'', qui repose sur plusieurs hypothèses valables dans les cas les plus généraux. La partie matière noire de cette thèse s'est concentrée sur un mécanisme récemment proposé, qui est le mécanisme de freeze-out par conversion, ou "coscattering''

    Au-delà du modèle standard : phénoménologie de matière noire exotique et contraintes du LHC

    No full text
    The Standard Model (SM) of particle physics is one of the most successful theories in science. Indeed, numerous SM prediction have been observed to be consistent with experimental measurements. However, some caveats hint for the incompleteness of the SM and push physicists to search for new physics. The ATLAS and CMS collaborations are carrying out an extensive and exciting physics programme at the LHC. Searches for new physics constitute a relevant part of this program. Simplified models are used to characterize the potential new physics signal. Reinterpreting the LHC results in more realistic scenarios than the simplified models is crucial in order to use the most of the physics sensitivity of the data.The work of this thesis focused on two aspects of reinterpretation, the improvement of reinterpretation tools and the phenomenology of beyond the Standard Model (BSM). The statistical combination of signal regions (SRs) allows to use more of the physics sensitivity of the experimental data in public tools. This thesis participated in the implementation of this feature in MadAnalysis5 and SModelS. Part of the focus was also given to phenomenological studies in order to demonstrates the impact of SR combination. Explaining the nature of dark matter (DM) is another area where the SM fails. Although many hypothetical particles with different properties are good DM candidates, the way they are produced in the early Universe can be classified into a few main mechanisms. The standard WIMP picture is based on the freeze-out mechanism, which is based on several assumptions that are valid in general cases. However, these assumptions can be broke for some scenarios, leading to exceptions to the standard WIMP picture. The DM portion of this thesis focused on a recently proposed mechanism, which is the conversion-driven freeze-out mechanism.Le Modèle Standard (MS) de la physique des particules est l'une des théories les plus réussies de la science. En effet, de nombreuses prédictions du MS se sont révélées cohérentes avec les mesures expérimentales. Cependant, certaines exceptions laissent entrevoir l'incomplétude du MS et poussent les physiciens à rechercher une nouvelle physique. Les collaborations ATLAS et CMS mènent un vaste et passionnant programme de physique au LHC. La recherche de nouvelle physique constitue une partie importante de ce programme. Des modèles simplifiés sont utilisés pour caractériser les potentiels signaux de nouvelle physique. La réinterprétation des résultats du LHC dans des scénarios plus réalistes que les modèles simplifiés est cruciale afin d'utiliser au mieux le potentiel des données expérimentales. Le travail de cette thèse s'est concentré sur deux aspects de la réinterprétation, l'amélioration des outils de réinterprétation et la phénoménologie au-delà du Modèle Standard (BSM). La combinaison statistique des SRs permet d'utiliser davantage la sensibilité physique des données expérimentales dans les outils publics. Cette thèse a participé à l'implémentation de cette fonctionnalité dans MadAnalysis5 et SModelS. Une partie de l'attention a également été accordée aux études phénoménologiques afin de démontrer l'impact de la combinaison de SRs. Expliquer la nature de la matière noire est un autre domaine où le MS échoue. Bien que de nombreuses particules hypothétiques ayant des propriétés différentes soient de bons candidats pour la matière noire, la façon dont elles sont produites dans l'Univers primitif peut être classée en quelques mécanismes principaux. Le paradigme standard des WIMPs est basé sur le mécanisme de "freeze-out'', qui repose sur plusieurs hypothèses valables dans les cas les plus généraux. La partie matière noire de cette thèse s'est concentrée sur un mécanisme récemment proposé, qui est le mécanisme de freeze-out par conversion, ou "coscattering''

    A SModelS interface for pyhf likelihoods

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    International audienceSModelS is an automatized tool enabling the fast interpretation of simplified model results from the LHC within any model of new physics respecting a Z2 symmetry. We here present a new version of SModelS, which can use the full likelihoods now provided by ATLAS in the form of pyhf JSON files. This much improves the statistical evaluation and therefore also the limit setting on new physics scenarios

    Signal region combination with full and simplified likelihoods in MadAnalysis 5

    No full text
    The statistical combination of disjoint signal regions in reinterpretation studies uses more of the data of an analysis and gives more robust results than the single signal region approach. We present the implementation and usage of signal region combination in MadAnalysis 5 through two methods: an interface to the pyhf package making use of statistical models in JSON-serialised format provided by the ATLAS collaboration, and a simplified likelihood calculation making use of covariance matrices provided by the CMS collaboration. The gain in physics reach is demonstrated 1.) by comparison with official mass limits for 4 ATLAS and 5 CMS analyses from the Public Analysis Database of MadAnalysis 5 for which signal region combination is currently available, and 2.) by a case study for an MSSM scenario in which both stops and sbottoms can be produced and have a variety of decays into charginos and neutralinos

    Signal region combination with full and simplified likelihoods in MadAnalysis 5

    Get PDF
    The statistical combination of disjoint signal regions in reinterpretation studies uses more of the data of an analysis and gives more robust results than the single signal region approach. We present the implementation and usage of signal region combination in MadAnalysis 5 through two methods: an interface to the pyhf package making use of statistical models in JSON-serialised format provided by the ATLAS collaboration, and a simplified likelihood calculation making use of covariance matrices provided by the CMS collaboration. The gain in physics reach is demonstrated 1.) by comparison with official mass limits for 4 ATLAS and 5 CMS analyses from the Public Analysis Database of MadAnalysis 5 for which signal region combination is currently available, and 2.) by a case study for an MSSM scenario in which both stops and sbottoms can be produced and have a variety of decays into charginos and neutralinos

    Signal region combination with full and simplified likelihoods in MadAnalysis 5

    No full text
    The statistical combination of disjoint signal regions in reinterpretation studies uses more of the data of an analysis and gives more robust results than the single signal region approach. We present the implementation and usage of signal region combination in MadAnalysis 5 through two methods: an interface to the pyhf package making use of statistical models in JSON-serialised format provided by the ATLAS collaboration, and a simplified likelihood calculation making use of covariance matrices provided by the CMS collaboration. The gain in physics reach is demonstrated 1.) by comparison with official mass limits for 4 ATLAS and 5 CMS analyses from the Public Analysis Database of MadAnalysis 5 for which signal region combination is currently available, and 2.) by a case study for an MSSM scenario in which both stops and sbottoms can be produced and have a variety of decays into charginos and neutralinos

    Constraining new physics with SModelS version 2

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    We present version 2 of SModelS, a program package for the fast reinterpretation of LHC searches for new physics on the basis of simplified model results. The major novelty of the SModelS v2 series is an extended topology description with a flexible number of particle attributes, such as spin, charge, decay width, etc. This enables, in particular, the treatment of a wide range of signatures with long-lived particles. Moreover, constraints from prompt and long-lived searches can be evaluated simultaneously in the same run. The current database includes results from searches for heavy stable charged particles, disappearing tracks, displaced jets and displaced leptons, in addition to a large number of prompt searches. The capabilities of the program are demonstrated by two physics applications: constraints on long-lived charged scalars in the scotogenic model, and constraints on the electroweak-ino sector in the Minimal Supersymmetric Standard Model
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