Laboratoire d'Annecy de Physique Théorique
facilityAnnecy, Rhône-Alpes, France
Research output, citation impact, and the most-cited recent papers from Laboratoire d'Annecy de Physique Théorique (France). Aggregated across the NobleBlocks index of 300M+ scholarly works.
Top-cited papers from Laboratoire d'Annecy de Physique Théorique
Boltzmann codes are used extensively by several groups for constraining cosmological parameters with Cosmic Microwave Background and Large Scale Structure data. This activity is computationally expensive, since a typical project requires from 10 4 to 10 5 Boltzmann code executions. The newly released code CLASS (Cosmic Linear Anisotropy Solving System) incorporates improved approximation schemes leading to a simultaneous gain in speed and precision. We describe here the three approximations used by CLASS for basic ΛCDM models, namely: a baryon-photon tight-coupling approximation which can be set to first order, second order or to a compromise between the two; an ultra-relativistic fluid approximation which had not been implemented in public distributions before; and finally a radiation streaming approximation taking reionisation into account.
We present the all-sky Planck catalogue of Sunyaev-Zeldovich (SZ) sources detected from the 29 month full-mission data. The catalogue (PSZ2) is the largest SZ-selected sample of galaxy clusters yet produced and the deepest systematic all-sky surveyof galaxy clusters. It contains 1653 detections, of which 1203 are confirmed clusters with identified counterparts in external data sets, and is the first SZ-selected cluster survey containing >103 confirmed clusters. We present a detailed analysis of the survey selection function in terms of its completeness and statistical reliability, placing a lower limit of 83% on the purity. Using simulations, we find that the estimates of the SZ strength parameter Y5R500are robust to pressure-profile variation and beam systematics, but accurate conversion to Y500 requires the use of prior information on the cluster extent. We describe the multi-wavelength search for counterparts in ancillary data, which makes use of radio, microwave, infra-red, optical, and X-ray data sets, and which places emphasis on the robustness of the counterpart match. We discuss the physical properties of the new sample and identify a population of low-redshift X-ray under-luminous clusters revealed by SZ selection. These objects appear in optical and SZ surveys with consistent properties for their mass, but are almost absent from ROSAT X-ray selected samples.
The matter power spectrum at comoving scales of $(1\ensuremath{-}40){h}^{\ensuremath{-}1}\text{ }\text{ }\mathrm{Mpc}$ is very sensitive to the presence of Warm Dark Matter (WDM) particles with large free-streaming lengths. We present constraints on the mass of WDM particles from a combined analysis of the matter power spectrum inferred from the large samples of high-resolution high signal-to-noise Lyman-$\ensuremath{\alpha}$ forest data of Kim et al. (2004) and Croft et al. (2002) and the cosmic microwave background data of WMAP. We obtain a lower limit of ${m}_{\mathrm{WDM}}\ensuremath{\gtrsim}550\text{ }\text{ }\mathrm{eV}$ ($2\ensuremath{\sigma}$) for early decoupled thermal relics and ${m}_{\mathrm{WDM}}\ensuremath{\gtrsim}2.0\text{ }\text{ }\mathrm{keV}$ ($2\ensuremath{\sigma}$) for sterile neutrinos. We also investigate the case where in addition to cold dark matter a light thermal gravitino with fixed effective temperature contributes significantly to the matter density. In that case the gravitino density is proportional to its mass, and we find an upper limit ${m}_{3/2}\ensuremath{\lesssim}16\text{ }\text{ }\mathrm{eV}$ ($2\ensuremath{\sigma}$). This translates into a bound on the scale of supersymmetry breaking, ${\ensuremath{\Lambda}}_{\mathrm{susy}}\ensuremath{\lesssim}260\text{ }\text{ }\mathrm{TeV}$, for models of supersymmetric gauge mediation in which the gravitino is the lightest supersymmetric particle.
Models for the latest stages of the cosmological evolution rely on a less solid theoretical and observational ground than the description of earlier stages like BBN and recombination. As suggested in a previous work by Vonlanthen et al., it is possible to tweak the analysis of CMB data in such way to avoid making assumptions on the late evolution, and obtain robust constraints on ''early cosmology parameters''. We extend this method in order to marginalise the results over CMB lensing contamination, and present updated results based on recent CMB data. Our constraints on the minimal early cosmology model are weaker than in a standard ΛCDM analysis, but do not conflict with this model. Besides, we obtain conservative bounds on the effective neutrino number and neutrino mass, showing no hints for extra relativistic degrees of freedom, and proving in a robust way that neutrinos experienced their non-relativistic transition after the time of photon decoupling. This analysis is also an occasion to describe the main features of the new parameter inference code MONTE PYTHON, that we release together with this paper. MONTE PYTHON is a user-friendly alternative to other public codes like COSMOMC, interfaced with the Boltzmann code CLASS.
This report reviews the study of open heavy-flavour and quarkonium production in high-energy hadronic collisions, as tools to investigate fundamental aspects of Quantum Chromodynamics, from the proton and nucleus structure at high energy to deconfinement and the properties of the Quark-Gluon Plasma. Emphasis is given to the lessons learnt from LHC Run 1 results, which are reviewed in a global picture with the results from SPS and RHIC at lower energies, as well as to the questions to be addressed in the future. The report covers heavy flavour and quarkonium production in proton-proton, proton-nucleus and nucleus-nucleus collisions. This includes discussion of the effects of hot and cold strongly interacting matter, quarkonium photoproduction in nucleus-nucleus collisions and perspectives on the study of heavy flavour and quarkonium with upgrades of existing experiments and new experiments. The report results from the activity of the SaporeGravis network of the I3 Hadron Physics programme of the European Union 7[Formula: see text] Framework Programme.
The present experimental results on neutrino flavour oscillations provide evidence for non-zero neutrino masses, but give no hint on their absolute mass scale, which is the target of beta decay and neutrinoless double-beta decay experiments. Crucial complementary information on neutrino masses can be obtained from the analysis of data on cosmological observables, such as the anisotropies of the cosmic microwave background or the distribution of large-scale structure. In this review we describe in detail how free-streaming massive neutrinos affect the evolution of cosmological perturbations. We summarize the current bounds on the sum of neutrino masses that can be derived from various combinations of cosmological data, including the most recent analysis by the WMAP team. We also discuss how future cosmological experiments are expected to be sensitive to neutrino masses well into the sub-eV range.
The Cosmic Linear Anisotropy Solving System (CLASS) is a new accurate Boltzmann code, designed to offer a more user-friendly and flexible coding environment to cosmologists. CLASS is very structured, easy to modify, and offers a rigorous way to control the accuracy of output quantities. It is also incidentally a bit faster than other codes. In this overview, we present the general principles of CLASS and its basic structure. We insist on the friendliness and flexibility aspects, while accuracy, physical approximations and performances are discussed in a series of companion papers.
We revisit Lyman-alpha bounds on the dark matter mass in Lambda Warm Dark Matter (Lambda-WDM) models, and derive new bounds in the case of mixed Cold plus Warm models (Lambda-CWDM), using a set up which is a good approximation for several theoretically well-motivated dark matter models. We combine WMAP5 results with two different Lyman-alpha data sets, including observations from the Sloan Digital Sky Survey. We pay a special attention to systematics, test various possible sources of error, and compare the results of different statistical approaches. Expressed in terms of the mass of a non-resonantly produced sterile neutrino, our bounds read m_NRP > 8 keV (frequentist 99.7% confidence limit) or m_NRP > 12.1 keV (Bayesian 95% credible interval) in the pure Lambda-WDM limit. For the mixed model, we obtain limits on the mass as a function of the warm dark matter fraction F_WDM. Within the mass range studied here (5 keV < m_NRP < infinity), we find that any mass value is allowed when F_WDM < 0.6 (frequentist 99.7% confidence limit); similarly, the Bayesian joint probability on (F_WDM, 1/m_NRP) allows any value of the mass at the 95% confidence level, provided that F_WDM < 0.35.
BACKGROUND: Isolated tears of the subscapularis occur less commonly than those involving the superior and posterior components of the rotator cuff. The purpose of the present study was to evaluate the structural integrity and clinical outcomes after arthroscopic repair of isolated subscapularis tears. METHODS: A prospective study of seventeen consecutive patients who were managed with an all-arthroscopic repair of the subscapularis tendon was performed. The study group included thirteen men and four women who had an average age of forty-seven years at the time of surgery. The average interval from the onset of symptoms to the time of surgery was twenty-four months. Thirteen tears were traumatic, and four were degenerative. Seven patients had a tear involving the superior third of the tendon, six had a tear involving the superior two-thirds of the tendon, and four had complete separation of the subscapularis from its insertion on the lesser tuberosity. Clinical findings were assessed for all patients preoperatively and postoperatively with use of the Constant and University of California at Los Angeles scoring systems, and all patients had postoperative computed tomographic arthrography studies to evaluate the structural integrity of the repair. RESULTS: The average duration of follow-up was twenty-nine months. When the preoperative findings were compared with the most recent findings, the average relative Constant score had improved from 58% to 96% (p < 0.05), the average University of California at Los Angeles score had improved from 16 to 32 points (p < 0.05), the average pain score had improved from 5.9 to 13.5 points (p < 0.05), the average forward flexion had improved from 146 degrees to 175 degrees (p < 0.05), the average external rotation had improved from 50 degrees to 60.3 degrees (p < 0.05), the average internal rotation had improved from the level of the sacrum to L1-L2 (p < 0.05), and the average abduction strength had improved from 7.4 to 15.6 points (p < 0.05). The structural integrity of the repair was completely intact in fifteen patients and was partially reruptured in two patients on the basis of computed tomographic arthrography. Progression of fatty infiltration of the subscapularis was not observed in any patient. Subjectively, twelve patients were very satisfied with the result, four were satisfied, and one was not satisfied. CONCLUSIONS: Arthroscopic repair of an isolated subscapularis tear can yield marked improvements in shoulder function, can significantly reduce pain, and can result in a durable structural repair. LEVEL OF EVIDENCE: Therapeutic Level IV.
We examine the theoretical motivations for long-lived particle (LLP) signals at the LHC in a comprehensive survey of standard model (SM) extensions. LLPs are a common prediction of a wide range of theories that address unsolved fundamental mysteries such as naturalness, dark matter, baryogenesis and neutrino masses, and represent a natural and generic possibility for physics beyond the SM (BSM). In most cases the LLP lifetime can be treated as a free parameter from the [Formula: see text]m scale up to the Big Bang Nucleosynthesis limit of [Formula: see text] m. Neutral LLPs with lifetimes above [Formula: see text]100 m are particularly difficult to probe, as the sensitivity of the LHC main detectors is limited by challenging backgrounds, triggers, and small acceptances. MATHUSLA is a proposal for a minimally instrumented, large-volume surface detector near ATLAS or CMS. It would search for neutral LLPs produced in HL-LHC collisions by reconstructing displaced vertices (DVs) in a low-background environment, extending the sensitivity of the main detectors by orders of magnitude in the long-lifetime regime. We study the LLP physics opportunities afforded by a MATHUSLA-like detector at the HL-LHC, assuming backgrounds can be rejected as expected. We develop a model-independent approach to describe the sensitivity of MATHUSLA to BSM LLP signals, and compare it to DV and missing energy searches at ATLAS or CMS. We then explore the BSM motivations for LLPs in considerable detail, presenting a large number of new sensitivity studies. While our discussion is especially oriented towards the long-lifetime regime at MATHUSLA, this survey underlines the importance of a varied LLP search program at the LHC in general. By synthesizing these results into a general discussion of the top-down and bottom-up motivations for LLP searches, it is our aim to demonstrate the exceptional strength and breadth of the physics case for the construction of the MATHUSLA detector.
We calculate the antiproton flux due to relic neutralino annihilations, in a two-dimensional diffusion model compatible with stable and radioactive cosmic ray nuclei. We find that the uncertainty in the primary flux induced by the propagation parameters alone is about two orders of magnitude at low energies, and it is mainly determined by the lack of knowledge of the thickness of the diffusive halo. On the contrary, different dark matter density profiles do not significantly alter the flux: a Novarro-Frenk-White distribution produces fluxes which are at most 20% higher than an isothermal sphere. The most conservative choice for propagation parameters and dark matter distribution normalization, together with current data on cosmic antiprotons, cannot lead to any definitive constraint on the supersymmetric parameter space, either in a low-energy effective minimal supersymmetric standard model, or in a minimal supergravity scheme. However, if the best choice for propagation parameters---corresponding to a diffusive halo of $L=4\mathrm{kpc}$---is adopted, some supersymmetric configurations with the neutralino mass ${m}_{\ensuremath{\chi}}\ensuremath{\lesssim}100\mathrm{GeV}$ should be considered as excluded. An enhancement flux factor---due for instance to a clumpy dark halo or a higher local dark matter density---would imply a more severe cut on the supersymmetric parameters.
Cosmic ray nuclei fluxes are expected to be measured with high precision in the near future. For instance, high quality data on the antiproton component could give important clues about the nature of the astronomical dark matter. A very good understanding of the different aspects of cosmic ray propagation is therefore necessary. In this paper, we use cosmic ray nuclei data to give constraints on the diffusion parameters. Propagation is studied with semi-analytical solutions of a diffusion model, and we give new analytical solutions for radioactively produced species. Our model includes convection and reacceleration as well as the standard energy losses. We perform a $χ^2$ analysis over B/C data for a large number of configurations obtained by varying the relevant parameters of the diffusion model. A very good agreement with B/C data arises for a number of configurations, all of which are compatible with sub-Fe/Fe data. Different source spectra $Q(E)$ and diffusion coefficients $K(E)$ have been tried, but for both parameters only one form gives a good fit. Another important result is that models without convection or without reacceleration are excluded. We find that the various parameters, i.e. the diffusion coefficient normalisation $K_0$ and spectral index $δ$, the halo thickness $L$, the Alfvén velocity $V_a$, and the convection velocity $V_c$ are strongly correlated. We obtain limits on the spectral index $δ$ of thediffusion coefficient, and in particular we exclude a Kolmogorov spectrum ($δ= 1/3$).
Abstract The Square Kilometre Array (SKA) is a planned large radio interferometer designed to operate over a wide range of frequencies, and with an order of magnitude greater sensitivity and survey speed than any current radio telescope. The SKA will address many important topics in astronomy, ranging from planet formation to distant galaxies. However, in this work, we consider the perspective of the SKA as a facility for studying physics. We review four areas in which the SKA is expected to make major contributions to our understanding of fundamental physics: cosmic dawn and reionisation; gravity and gravitational radiation; cosmology and dark energy; and dark matter and astroparticle physics. These discussions demonstrate that the SKA will be a spectacular physics machine, which will provide many new breakthroughs and novel insights on matter, energy, and spacetime.
Background: Isolated tears of the subscapularis occur less commonly than those involving the superior and posterior components of the rotator cuff. The purpose of the present study was to evaluate the structural integrity and clinical outcomes after arthroscopic repair of isolated subscapularis tears. Methods: A prospective study of seventeen consecutive patients who were managed with an all-arthroscopic repair of the subscapularis tendon was performed. The study group included thirteen men and four women who had an average age of forty-seven years at the time of surgery. The average interval from the onset of symptoms to the time of surgery was twenty-four months. Thirteen tears were traumatic, and four were degenerative. Seven patients had a tear involving the superior third of the tendon, six had a tear involving the superior two-thirds of the tendon, and four had complete separation of the subscapularis from its insertion on the lesser tuberosity. Clinical findings were assessed for all patients preoperatively and postoperatively with use of the Constant and University of California at Los Angeles scoring systems, and all patients had postoperative computed tomographic arthrography studies to evaluate the structural integrity of the repair. Results: The average duration of follow-up was twenty-nine months. When the preoperative findings were compared with the most recent findings, the average relative Constant score had improved from 58% to 96% (p < 0.05), the average University of California at Los Angeles score had improved from 16 to 32 points (p < 0.05), the average pain score had improved from 5.9 to 13.5 points (p < 0.05), the average forward flexion had improved from 146° to 175° (p < 0.05), the average external rotation had improved from 50° to 60.3° (p < 0.05), the average internal rotation had improved from the level of the sacrum to L1-L2 (p < 0.05), and the average abduction strength had improved from 7.4 to 15.6 points (p < 0.05). The structural integrity of the repair was completely intact in fifteen patients and was partially reruptured in two patients on the basis of computed tomographic arthrography. Progression of fatty infiltration of the subscapularis was not observed in any patient. Subjectively, twelve patients were very satisfied with the result, four were satisfied, and one was not satisfied. Conclusions: Arthroscopic repair of an isolated subscapularis tear can yield marked improvements in shoulder function, can significantly reduce pain, and can result in a durable structural repair. Level of Evidence: Therapeutic Level IV. See Instructions to Authors for a complete description of levels of evidence.
The discovery of the Higgs boson in 2012, by the ATLAS and CMS experiments, was a success achieved with only a percent of the entire dataset foreseen for the LHC. It opened a landscape of possibilities in the study of Higgs boson properties, Electroweak Symmetry breaking and the Standard Model in general, as well as new avenues in probing new physics beyond the Standard Model. Six years after the discovery, with a conspicuously larger dataset collected during LHC Run 2 at a 13 TeV centre-of-mass energy, the theory and experimental particle physics communities have started a meticulous exploration of the potential for precision measurements of its properties. This includes studies of Higgs boson production and decays processes, the search for rare decays and production modes, high energy observables, and searches for an extended electroweak symmetry breaking sector. This report summarises the potential reach and opportunities in Higgs physics during the High Luminosity phase of the LHC, with an expected dataset of pp collisions at 14 TeV, corresponding to an integrated luminosity of 3~ab$^{-1}$. These studies are performed in light of the most recent analyses from LHC collaborations and the latest theoretical developments. The potential of an LHC upgrade, colliding protons at a centre-of-mass energy of 27 TeV and producing a dataset corresponding to an integrated luminosity of 15~ab$^{-1}$, is also discussed.
We present a new flexible, fast and accurate way to implement massive neutrinos, warm dark matter and any other non-cold dark matter relics in Boltzmann codes. For whatever analytical or numerical form of the phase-space distribution function, the optimal sampling in momentum space compatible with a given level of accuracy is automatically found by comparing quadrature methods. The perturbation integration is made even faster by switching to an approximate viscous fluid description inside the Hubble radius, which differs from previous approximations discussed in the literature. When adding one massive neutrino to the minimal cosmological model, CLASS becomes just 1.5 times slower, instead of about 5 times in other codes (for fixed accuracy requirements). We illustrate the flexibility of our approach by considering a few examples of standard or non-standard neutrinos, as well as warm dark matter models.
We have constructed all-sky Compton parameters maps, y-maps, of the thermal Sunyaev-Zeldovich (tSZ) effect by applying specifically tailored component separation algorithms to the 30 to 857 GHz frequency channel maps from the Planck satellite.These reconstructed y-maps are delivered as part of the Planck 2015 release.The y-maps are characterized in terms of noise properties and residual foreground contamination, mainly thermal dust emission at large angular scales, and cosmic infrared background and extragalactic point sources at small angular scales.Specific masks are defined to minimize foreground residuals and systematics.Using these masks, we compute the y-map angular power spectrum and higher order statistics.From these we conclude that the y-map is dominated by tSZ signal in the multipole range, 20 < < 600.We compare the measured tSZ power spectrum and higher order statistics to various physically motivated models and discuss the implications of our results in terms of cluster physics and cosmology.
This is a pedagogical introduction to the harmonic superspace method in extended supersymmetry. Inspired by exciting developments in superstring theory, it provides a systematic treatment of the quantum field theories with N=2 and N=3 supersymmetry in harmonic superspace. The authors present the harmonic superspace approach as a means of providing an off-shell description of the N=2 supersymmetric theories, both at the classical and quantum levels. Furthermore, they show how it offers a unique way to construct an off-shell formulation of a theory with higher supersymmetry, namely the N=3 supersymmetric Yang-Mills theory. Harmonic Superspace makes manifest many remarkable geometric properties of the N=2 theories, for example, the one-to-one correspondence between N=2 supersymmetric matter, and hyper-Kähler and quaternionic manifolds. This book will be of interest to researchers and graduate students working in the areas of supersymmetric quantum field theory, string theory and complex geometries.
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In peripheral collisions at LHC, part of the large angular momentum of the \ncolliding ions could be collectively transferred to the midrapidity \ninteraction region giving rise to a spinning quark gluon plasma fireball. \nIf the intrinsic angular momentum of the QGP fireball is large enough, there \nwill be remarkable effects on several observables such as elliptic flow, \ntransverse momentum spectra and hadron multiplicities. \nBy taking advantage of a recent full calculation of the microcanonical and \ncanonical ensembles of ideal relativistic quantum gases at fixed intrinsic \nangular momentum, we give quantitative predictions of those observables \nat LHC. In a statistically equilibrated spinning fireball, the predicted \nazimuthal momentum anisotropy is very similar to that generated by the \npressure gradients in usual hydrodynamical approach; transverse momentum spectra \nare broadened; the chemical freeze-out temperatures determined \nby means of hadronic abundances could decrease with respect to central \ncollisions. However, the most peculiar feature is an azimuthal anisotropic \nnet polarization of produced hadrons, for which we provide quantitative \npredictions and momentum dependence.