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

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

Phénoménologie de Précision au LHC et caractérisation des incertitudes théoriques

In light of the recent discovery of a Higgs boson at the LHC and of the contemporary absence of signals of new physics beyond the Standard Model (SM), precision physics has become the most important aim of the LHC physics program. Precision physics requires not only a thorough control over experimental uncertainties but also a good understanding of theoretical ones. In this thesis we approach the problem along two lines. At first we study the so-called missing higher order uncertainty in QCD with the Cacciari-Houdeau (CH) method and the scale variation procedure. As a by product we also provide an extension of the CH method to observables with initial state hadrons. Next we study the problem of the precise prediction and of the uncertainty estimation for two important Higgs observables: the total inclusive cross section and the transverse momentum distribution. With respect to the former, we study the production in gluon fusion and bottom annihilation (and its related uncertainties) in the Minimal Supersymmetric Standard Model (MSSM) for the production of the neutral scalars and of the pseudoscalar using the code SusHi. With respect to the latter, we study the transverse momentum distribution using our Monte Carlo event generators in the POWHEG-BOX framework for gluon fusion in the SM, MSSM and Two Higgs-Doublet Model (2HDM), with particular attention to the problem of including correctly the full of effect of the quarks running in the loop.En raison de la récente découverte du boson de Higgs au LHC et de l'absence de nouveaux signaux de physique au-delà du Modèle Standard (MS), la physique de précision est maintenant l'objectif le plus important du programme de physique du LHC. Elle n'a besoin pas seulement d'un contrôle total sur les incertitudes expérimentales mais aussi d'une compréhension des incertitudes théoriques. Dans cette thèse on approche ce problème en deux façons. Notre premier travail est l’étude des incertitudes dues au fait que la série perturbative est calculée seulement à un ordre fini. On prend comme théorie la QCD et utilise le modèle de Cacciari et Houdeau (CH) et la procédure de variation d’échelle pour faire une étude des leur efficacité. Aussi on fait l'extension du modèle CH au cas des observables avec des hadrons dans l’état initial. Après on étudie le problème de la prédiction précise et de l'estimation de l'incertitude des deux observables du boson de Higgs: la section efficace totale et la distribution de l'impulsion transverse. La première est étudiée dans deux canaux de production, la fusion des gluons et l'annihilation des bottom quarks, dans le Minimal Supersymmetric Standard Model (MSSM), pour la production des scalaires neutres et du pseudoscalaire en utilisant le code SusHi. L'impulsion transverse est étudiée avec notre logiciel Monte Carlo (conçu dans le cadre du POWHEG-BOX) du processus de gluon fusion dans le MS, MSSM et le Two Higgs Doublet Model (2HDM), avec une attention particulière à l'inclusion des amplitudes complètes pour les quarks

Benchmark Scenarios for MSSM Higgs Boson Searches at the LHC

A number of benchmark scenarios for MSSM Higgs boson searches at the LHC have been proposed in recent years, and some of them are already in use by the ATLAS and CMS collaborations for the interpretation of their results from Run 2. The LHC Higgs Working Group provides a set of ROOT files that contain the numerical predictions for masses, branching ratios and production cross sections in these scenarios, relying on state-of-the art calculations implemented in public codes. In this document we first summarize the theory setup and the definitions of the scenarios, and then discuss the technical details of the ROOT files. A C++ interface to access these data is presented as well

Reinterpretation of LHC results for new physics: status and recommendations after Run 2

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

Higgs boson potential at colliders: status and perspectives

This document summarises the current theoretical and experimental status of the di-Higgs boson production searches, and of the direct and indirect constraints on the Higgs boson self-coupling, with the wish to serve as a useful guide for the next years. The document discusses the theoretical status, including state-of-the-art predictions for di-Higgs cross sections, developments on the effective field theory approach, and studies on specific new physics scenarios that can show up in the di-Higgs final state. The status of di-Higgs searches and the direct and indirect constraints on the Higgs self-coupling at the LHC are presented, with an overview of the relevant experimental techniques, and covering all the variety of relevant signatures. Finally, the capabilities of future colliders in determining the Higgs self-coupling are addressed, comparing the projected precision that can be obtained in such facilities. The work has started as the proceedings of the Di-Higgs workshop at Colliders, held at Fermilab from the 4th to the 9th of September 2018, but it went beyond the topics discussed at that workshop and included further developments. Part III of the document reviews the capabilities of future colliders to establish the the size of Higgs self-coupling both qualitatively and quantitatively