Christophe Grojean
A5008291403- Particle physics theoretical and experimental studies
- Black Holes and Theoretical Physics
- Cosmology and Gravitation Theories
- Dark Matter and Cosmic Phenomena
- Quantum Chromodynamics and Particle Interactions
- Particle Detector Development and Performance
- High-Energy Particle Collisions Research
- Computational Physics and Python Applications
- Particle Accelerators and Free-Electron Lasers
- International Science and Diplomacy
- Distributed and Parallel Computing Systems
- Superconducting Materials and Applications
- Neutrino Physics Research
- Noncommutative and Quantum Gravity Theories
- Atomic and Subatomic Physics Research
- Astrophysics and Cosmic Phenomena
- Relativity and Gravitational Theory
- Medical Imaging Techniques and Applications
- Nonlinear Waves and Solitons
- Complex Systems and Time Series Analysis
- Scientific Computing and Data Management
- Muon and positron interactions and applications
- Advanced Algebra and Geometry
- Particle accelerators and beam dynamics
- Pulsars and Gravitational Waves Research
Deutsches Elektronen-Synchrotron DESY
2016-2024
European Organization for Nuclear Research
2007-2024
Humboldt-Universität zu Berlin
2018-2024
University of Padua
2021-2022
Istituto Nazionale di Fisica Nucleare, Sezione di Padova
2021-2022
University of Manchester
2022
Universitat Autònoma de Barcelona
2012-2016
Institució Catalana de Recerca i Estudis Avançats
2012-2016
Institute for High Energy Physics
2013-2016
Cornell University
2016
The Review summarizes much of particle physics and cosmology. Using data from previous editions, plus 3,062 new measurements 721 papers, we list, evaluate, average measured properties gauge bosons the recently discovered Higgs boson, leptons, quarks, mesons, baryons. We summarize searches for hypothetical particles such as supersymmetric particles, heavy bosons, axions, dark photons, etc. All search limits are listed in Summary Tables. also give numerous tables, figures, formulae, reviews...
The Review summarizes much of particle physics and cosmology. Using data from previous editions, plus 2,873 new measurements 758 papers, we list, evaluate, average measured properties gauge bosons the recently discovered Higgs boson, leptons, quarks, mesons, baryons. We summarize searches for hypothetical particles such as supersymmetric particles, heavy bosons, axions, dark photons, etc. Particle search limits are listed in Summary Tables. give numerous tables, figures, formulae, reviews...
Abstract The Review summarizes much of particle physics and cosmology. Using data from previous editions, plus 2,143 new measurements 709 papers, we list, evaluate, average measured properties gauge bosons the recently discovered Higgs boson, leptons, quarks, mesons, baryons. We summarize searches for hypothetical particles such as supersymmetric particles, heavy bosons, axions, dark photons, etc. Particle search limits are listed in Summary Tables. give numerous tables, figures, formulae,...
This Report summarizes the results of activities in 2012 and first half 2013 LHC Higgs Cross Section Working Group. The main goal working group was to present state art Physics at LHC, integrating all new that have appeared last few years. report follows Handbook Sections: 1. Inclusive Observables (CERN-2011-002) second 2. Differential Distributions (CERN-2012-002). After discovery a boson mid-2012 this focuses on refined prediction Standard Model (SM) phenomenology around experimentally...
It has recently been pointed out that global solutions of Einstein's equations for a 3-brane universe embedded in 4 spatial dimensions give rise to Friedmann equation the form H ~ rho on brane, instead usual (rho)^{1/2}, which is inconsistent with cosmological observations. We remedy this problem by adding constants brane and bulk, as recent scenario Randall Sundrum. Our observation allows normal expansion during nucleosynthesis, but faster than very early universe, could be helpful...
This paper describes the physics case for a new fixed target facility at CERN SPS. The SHiP (Search Hidden Particles) experiment is intended to hunt in largely unexplored domain of very weakly interacting particles with masses below Fermi scale, inaccessible LHC experiments, and study tau neutrino physics. same proton beam setup can be used later look decays tau-leptons lepton flavour number non-conservation, $\tau\to 3\mu$ search weakly-interacting sub-GeV dark matter candidates. We discuss...
The summarizes much of particle physics and cosmology. Using data from previous editions, plus 2,717 new measurements 869 papers, we list, evaluate, average measured properties gauge bosons the recently discovered Higgs boson, leptons, quarks, mesons, baryons. We summarize searches for hypothetical particles such as supersymmetric particles, heavy bosons, axions, dark photons, etc. Particle search limits are listed in Summary Tables. give numerous tables, figures, formulae, reviews topics...
We consider extra dimensional gauge theories on an interval. first review the derivation of consistent boundary conditions (BC's) from action principle. These BC's include choices that give rise to breaking symmetries. The could be chosen coincide with those commonly applied in orbifold theories, but there are many more possibilities. To investigate nature symmetry via we calculate elastic scattering amplitudes for longitudinal bosons. find using a set terms these explicitly grow energy...
We present a 5D gauge theory in warped space based on bulk $\mathrm{SU}(2{)}_{L}\ifmmode\times\else\texttimes\fi{}\mathrm{SU}(2{)}_{R}\ifmmode\times\else\texttimes\fi{}\mathrm{U}(1{)}_{B\ensuremath{-}L}$ group where the symmetry is broken by boundary conditions. The breaking pattern and mass spectrum resemble that standard model (SM). To leading order warp factor $\ensuremath{\rho}$ parameter coupling of $Z$ ($S$ parameter) are as SM, while corrections expected at level percent. From...
If there was a first-order phase transition in the early universe, should be an associated stochastic background of gravitational waves. In this paper, we point out that characteristic frequency spectrum due to transitions which took place temperature range $100\text{ }\text{ }\mathrm{GeV}--{10}^{7}\text{ }\mathrm{GeV}$ is precisely window will probed by second generation space-based interferometers such as big bang observer (BBO). Taking into account astrophysical foreground, determine type...
The discovery by the ATLAS and CMS experiments of a new boson with mass around 125 GeV measured properties compatible those Standard-Model Higgs boson, coupled absence discoveries phenomena beyond Standard Model at TeV scale, has triggered interest in ideas for future factories. A circular e+e- collider hosted 80 to 100 km tunnel, TLEP, is among most attractive solutions proposed so far. It clean experimental environment, produces high luminosity top-quark, W Z studies, accommodates multiple...
This document aims to provide an assessment of the potential future colliding beam facilities perform Higgs boson studies. The analysis builds on submissions made by proponents colliders European Strategy Update process, and takes as its point departure results expected at completion HL-LHC program. report presents quantitative many aspects physics for collider projects sufficient maturity using uniform methodologies.
We reconsider the effective Lagrangian that describes a light Higgs-like boson and better clarify few issues which were not exhaustively addressed in previous literature. In particular we highlight strategy to determine whether dynamics responsible for electroweak symmetry breaking is weakly or strongly interacting. also discuss how can be implemented into automatic tools calculation of Higgs decay rates production cross sections.
We study the possibility of a first-order electroweak phase transition due to dimension-six operator in effective Higgs potential. In contrast with previous attempts make strongly as required by baryogenesis, we do not rely on large one-loop thermally generated cubic interactions. Instead, augment standard model theory operator. This addition enables strong develop even boson mass well above current direct limit 114 GeV. The ${\ensuremath{\varphi}}^{6}$ term can be for instance dynamics at...
We consider fermions on an extra dimensional interval. find the boundary conditions at ends of interval that are consistent with variational principle, and explain which ones arise in various physical circumstances. apply these results to Higgsless models electroweak symmetry breaking, where is not broken by a scalar vacuum expectation value, but rather gauge fields. show it possible set for bulk would give realistic fermion mass spectrum without presence Higgs scalar, present some sample...
The hierarchy problem and the electroweak data, together, provide a plausible motivation for considering light Higgs emerging as pseudo-Goldstone boson from strongly-coupled sector. In that scenario, rates production decay differ significantly those in Standard Model. However, one genuine strong coupling signature is growth with energy of scattering amplitudes among Goldstone bosons, longitudinally polarized vector bosons well itself. rate double fusion thus enhanced respect to its...
We consider the possibility that standard model Higgs fields may originate from extra components of higher dimensional gauge fields. Theories this type considered before have had problems accommodating fermion content and Yukawa couplings different coupling. Considering orbifolds based on Abelian discrete groups we are led to a 6 ${G}_{2}$ theory compactified ${T}^{2}{/Z}_{4}.$ This can naturally produce SM with right quantum numbers while predicting value weak mixing angle...
We outline a method for characterizing deviations from the properties of Standard Model (SM) Higgs boson. apply it to current data in order characterize up which degree SM boson interpretation is consistent with experiment. find that set at 82 % confidence level, based on excess events reported by CMS and ATLAS, are interpreted be related mass scale mh = 124-126 GeV, published CL_s exclusion regions. perform global fit terms two parameters deviation value gauge fermion couplings minima...
We consider various constraints on Higgsless models of electroweak symmetry breaking based a bulk SU(2)_L x SU(2)_R U(1)_{B-L} gauge group in warped space. First we show that the S parameter which is positive if fermions are localized Planck brane can be lowered (or made vanishing) by changing localization light fermions. If wave function almost flat their coupling to boson KK modes will close vanishing, and therefore contributions suppressed. At same time experimental bounds such Z' W'...
This report summarizes the work of Energy Frontier Higgs Boson working group 2013 Community Summer Study (Snowmass). We identify key elements a precision physics program and document potential future experimental facilities as elucidated during Snowmass study. study couplings to gauge boson fermion pairs, double production for self-coupling, its quantum numbers $CP$-mixing in couplings, mass total width, prospects direct searches additional bosons extensions Standard Model. Our includes...
A bstract We compute the renormalization of dimension six Higgs-gauge boson operators that can modify h → γγ rate at tree-level. Operator mixing is shown to lead an important modification new physics effects which has been neglected in past calculations. also find usual formula for S oblique parameter contribution these needs additional terms be consistent with group evolution. study implications our results Higgs phenomenology and models attempt explain a deviation rate. derive relation...