MadAnalysis 5: status and new developments

MadAnalysis 5 is a new Python/C++ package facilitating phenomenological analyses that can be performed in the framework of Monte Carlo simulations of collisions to be produced in high-energy physics experiments. It allows, by means of a user-friendly interpreter, to perform professional physics analyses in a very simple way. Starting from event samples as generated by any Monte Carlo event generator, large classes of selections can be implemented through intuitive commands, many standard kinematical distributions can be automatically represented by histograms and all results are eventually gathered into detailed Html and latex reports. In this work, we briefly report on the latest developments of the code, focusing on the interface to the FastJet program dedicated to jet reconstruction.Comment: 8 pages, 1 figure, contribution to the proceedings of the 15th International Workshop of advanced computing and analysis techniques (ACAT 2013), 16-21 May 2013, China; version to appear in the proceeding

Designing and recasting LHC analyses with MadAnalysis 5

We present an extension of the expert mode of the MadAnalysis 5 program dedicated to the design or reinterpretation of high-energy physics collider analyses. We detail the predefined classes, functions and methods available to the user and emphasize the most recent developments. The latter include the possible definition of multiple sub-analyses and a novel user-friendly treatment for the selection criteria. We illustrate this approach by two concrete examples: a CMS search for supersymmetric partners of the top quark and a phenomenological analysis targeting hadronically decaying monotop systems.Comment: 17 pages, 3 figures, 10 tables; version accepted by EPJ

Monotop phenomenology at the Large Hadron Collider

We investigate new physics scenarios where systems comprised of a single top quark accompanied by missing transverse energy, dubbed monotops, can be produced at the LHC. Following a simplified model approach, we describe all possible monotop production modes via an effective theory and estimate the sensitivity of the LHC, assuming 20 fb$^{-1}$ of collisions at a center-of-mass energy of 8 TeV, to the observation of a monotop state. Considering both leptonic and hadronic top quark decays, we show that large fractions of the parameter space are reachable and that new physics particles with masses ranging up to 1.5 TeV can leave hints within the 2012 LHC dataset, assuming moderate new physics coupling strengths.Comment: 17 pages, 12 figures, 3 table

USP45 and Spindly are part of the same complex implicated in cell migration

Abstract Ubiquitylation is a protein modification implicated in several cellular processes. This process is reversible by the action of deubiquinating enzymes (DUBs). USP45 is a ubiquitin specific protease about which little is known, aside from roles in DNA damage repair and differentiation of the vertebrate retina. Here, by using mass spectrometry we have identified Spindly as a new target of USP45. Our data show that Spindly and USP45 are part of the same complex and that their interaction specifically depends on the catalytic activity of USP45. In addition, we describe the type of ubiquitin chains associated with the complex that can be cleaved by USP45, with a preferential activity on K48 ubiquitin chain type and potentially K6. Here, we also show that Spindly is mono-ubiquitylated and this can be specifically removed by USP45 in its active form but not by the catalytic inactive form. Lastly, we identified a new role for USP45 in cell migration, similar to that which was recently described for Spindly

A comprehensive approach to dark matter studies: exploration of simplified top-philic models

Studies of dark matter lie at the interface of collider physics, astrophysics and cosmology. Constraining models featuring dark matter candidates entails the capability to provide accurate predictions for large sets of observables and compare them to a wide spectrum of data. We present a framework which, starting from a model lagrangian, allows one to consistently and systematically make predictions, as well as to confront those predictions with a multitude of experimental results. As an application, we consider a class of simplified dark matter models where a scalar mediator couples only to the top quark and a fermionic dark sector (i.e. the simplified top-philic dark matter model). We study in detail the complementarity of relic density, direct/indirect detection and collider searches in constraining the multi-dimensional model parameter space, and efficiently identify regions where individual approaches to dark matter detection provide the most stringent bounds. In the context of collider studies of dark matter, we point out the complementarity of LHC searches in probing different regions of the model parameter space with final states involving top quarks, photons, jets and/or missing energy. Our study of dark matter production at the LHC goes beyond the tree-level approximation and we show examples of how higher-order corrections to dark matter production processes can affect the interpretation of the experimental results.Comment: 52 pages, 23 figure

ODSurf : Modélisation et réalisation d'une couche de roulement de chaussée optimisée, dense et peu bruyante

ODSurf project is following a previous P2RN project dealing with the emission and propagation of rolling noise, carried out in the framework of the German-French collaboration DEUFRAKO. During P2RN, an optimum pavement texture in terms of the noise emission was calculated. The current ODSurf project was mainly dedicated to the development and implementation of low noise new technologies and new materials adapted to urban environment. Original solutions have been investigated, implemented and tested on-site. In parallel to these technological approaches, new models have been developed to better characterize various physical phenomena produced when a tyre is rolling on a textured pavement. Vibration phenomena, air pumping and the horn effect were specifically studied and the main results are detailed in this document. In addition to the modelling approach, this project includes a strong experimental component useful for model validation and also to allow an acoustic classification of road surfaces. The measures presented in this report were carried out both on test tracks and actual site on which were positioned the optimized conventional or industrially designed coatings, both in France and Germany. Finally, this report is ending with the common database "DEUFRABASE". It includes the noise produced by light and heavy vehicles running on a large panel of French and German road surfaces for various propagation configurations. Updated at the end of the project, this database posted on the Ifsttar server will be soon freely available online. From its current design, it will easily allow regular updates in terms of site configurations and new road surfaces. It thus will be a good tool to estimate the acoustic impact of traffic for many suburban and urban situations. Following the results achieved during the project, the next steps will concern on one hand, the improvement and integration of the various modelling approaches of different tyre noise generation phenomena in a "unique" tool in order to have an overall estimation of the impact of road surfaces on the sound level produced by road traffic and secondly, to extend the DEUFRABASE to more realistic situations.Le projet ODSurf fait suite à un précédent projet P2RN, relatif à l'émission et la propagation du bruit de roulement, réalisé dans le cadre de la collaboration franco-allemande DEUFRAKO. Au cours de P2RN, une texture de chaussée optimale du point de vue de l'émission sonore avait été calculée. L'actuel projet ODSurf a été principalement dédié à l'élaboration et la mise en oeuvre de nouvelles technologies à faible bruit et de nouveaux matériaux adaptés au milieu urbain. Des solutions originales ont été imaginées, mises en oeuvre sur site et testées. Parallèlement à ces approches technologiques, de nouveaux modèles ont été développés pour mieux caractériser les divers phénomènes physiques mis en jeu lors du roulement d'un pneumatique sur une chaussée texturée. Les phénomènes vibratoires, de pompage d'air ainsi que l'effet dièdre ont été plus particulièrement étudiés et les principaux résultats sont détaillés dans le présent document. Outre l'approche modélisation, ce projet a fait l'objet d'une forte composante expérimentale utile à la fois pour la validation des modèles mais aussi pour permettre une classification acoustique des revêtements routiers. Les mesures présentées dans ce rapport ont été réalisées à la fois sur pistes d'essai et sur site réel sur lesquels ont été mis en place les revêtements optimisés de conception classique ou industrielle, tant en France et qu'en Allemagne. Enfin, ce document se termine par la base de données commune « DEUFRABASE ». Elle regroupe les émissions sonores produites par le roulement de véhicules légers et lourds sur un large panel de revêtements routiers français et allemands pour diverses configurations de propagation. Mise à jour en fin de projet, cette base déposée sur le serveur de l'Ifsttar sera prochainement accessible gratuitement en ligne. De par sa conception actuelle, elle permettra aisément des mises à jour régulières tant en termes de configurations de sites que de nouveaux revêtements de chaussée. Elle permettra ainsi d'être un bon outil pour estimer l'impact acoustique du trafic routier pour de multiples configurations périurbaines et urbaines. A la lumière des résultats enregistrés au cours de ce projet, les étapes futures concerneront d'une part, l'amélioration et l'intégration des diverses approches de modélisation des différents phénomènes de génération de bruit de roulement dans un outil « unique » afin d'avoir une estimation globale de l'impact des couches de roulement sur le niveau sonore produit par le trafic routier et d'autre part, d'étendre la DEUFRABASE à un plus grand nombre de situations réalistes

Probing displaced top quark signature at the LHC Run 3

In the context of prospective studies for searches of new physics at the LHC Run 3, this paper investigates the relevance of using top quarks produced from new long-lived particles, and detected in the tracker volume of the ATLAS and CMS experiments. Such a signature, referred to as displaced top quarks, leads to final states containing displaced vertices and a high multiplicity of displaced jets and tracks, thanks to the top quark decays. Therefore, it is a possible powerful tool for searching for new long-lived particles. Three simplified models based on supersymmetry are explicitly designed for the study of this signature. They differ according to the nature of the long-lived heavy particle which produces at least one top quark: electrically neutral or charged, coloured or non-coloured long-lived particle. For each model, a wide region of parameter space, consistent with a reasonable number of displaced top quarks decaying in a typical tracker volume has been probed. From this study, promising benchmarks are defined and experimental guidelines are suggested.Comment: 24 pages, 48 figure

Probing top anomalous couplings at the LHC with trilepton signatures in the single top mode

We investigate trilepton final states to probe top anomalous couplings at the Large Hadron Collider. We focus on events originating from the associated production of a single top quark with a Z-boson, a channel sensitive to several flavor-changing neutral interactions of top and up/charm quarks. In particular, we explore a way to access simultaneously their anomalous couplings to Z-bosons and gluons and derive the discovery potential of trilepton final states to such interactions with 20 fb-1 of 8 TeV collisions. We show that effective coupling strengths of O(0.1-1) TeV-1 can be reached. Equivalently, branching fractions of top quarks into lighter quarks and gluons or Z-bosons can be constrained to be below O(0.1-1)%.Comment: 5 pages, 3 figures, 1 table; version accepted by PL