HAL Mines Nantes
Not a member yet
7271 research outputs found
Sort by
GWSim: A python package to create GW mock samples for different astrophysical populations and cosmological models of binary black holes
No full textInternational audiencePrecision cosmology with gravitational wave (GW) sources requires understanding the interplay between GW source population and cosmological parameters governing the dynamics of the Universe. With the fast increase of GW detections, for exploring many aspects of cosmology and fundamental physics it is necessary to develop a tool which can simulate GW mock samples for several population and cosmological models with and without a galaxy catalog. We have developed a new code called GWSim, allowing to make GW mock events from a large range of configurations, varying the cosmology, the merger rate, and the GW source parameters (mass and spin distributions in particular), for a given network of GW detectors. We restrict the cosmology to spatially flat universes, including models with varying dark energy equation of state. GWSim provides each mock event with a position in the sky and a redshift; these values can be those of random host galaxies coming from an isotropic and homogeneous simulated Universe or a user-supplied galaxy catalog. We use realistic detector configurations of the LIGO and Virgo network of detectors to show the performance of this code for the latest observation runs and the upcoming observation run
Underlying-event properties in pp and p–Pb collisions at = 5.02 TeV
No full textInternational audienceWe report about the properties of the underlying event measured with ALICE at the LHC in pp and p–Pb collisions at = 5.02 TeV. The event activity, quantified by charged-particle number and summed-p densities, is measured as a function of the leading-particle transverse momentum . These quantities are studied in three azimuthal-angle regions relative to the leading particle in the event: toward, away, and transverse. Results are presented for three different p thresholds (0.15, 0.5 and 1 GeV/c) at mid-pseudorapidity (|η| 10 {p}_{\textrm{T}}^{\textrm{trig}} $ values the event activity is slightly higher in p–Pb than in pp collisions. The measurements are compared with predictions from the PYTHIA 8 and EPOS LHC Monte Carlo event generators.[graphic not available: see fulltext
Adsorption of methane and carbon dioxide by water-saturated clay minerals and clay rocks
No full textInternational audienceUnderstanding the effects of water on gas adsorption in geological media is of high importance in order to efficiently control numerous subsurface engineering process operating at gas/rock interfaces. Due to preferential interaction with clay surfaces, water fills their porous body, greatly reducing CH4 and CO2 adsorption capacity. In order to quantitatively describe CH4 and CO2 adsorption by hydrated clay minerals, this work proposes to rely on the mechanism of gas uptake by dissolution in pre-adsorbed pore water. This approach was employed to characterise water-saturated porous media of increasing complexity: mesoporous silica SBA-15 and silica gel with different pore sizes and geometry, isolated illite and montmorillonite and natural clay-rich rock (the Callovo-Oxfordian formation – COx, France) in powdered and crushed states. It was found that the solubility in water can reliably explain the CO2 uptakes by hydrated pore systems regardless of their nature as well as the CH4 uptakes, but only for solids with large mesopores and montmorillonite mineral. A so called “adsorption enhanced gas uptake in pore water” for CH4, exceeding its solubility in bulk water by a factor of 5–8, was observed for the systems with narrow pore sizes, highlighting the impact of surface energy on gas uptake and the occurrence of the interaction of weakly-soluble methane with the surface, promoting its uptake in comparison to pure dissolution
Hard parton dispersion in the quark-gluon plasma, non-perturbatively
No full textInternational audienceJet-medium interactions receive large non-perturbative contributions from classical gluons, i.e. in-frared gluons with high occupation numbers. These contributions affect transverse jet momentumbroadening and medium-induced radiation. Both depend significantly on the in-medium dispersionof hard partons, encoded in their so-called asymptotic mass.In this talk, I shall show how the analytical properties of thermal amplitudes allow for a non-perturbativedetermination of the IR classical contribution through lattice determinations in the dimensionally-reduced Effective Theory of hot QCD, EQCD. I will show how these existing lattice determinationsneed to be complemented by perturbative two-loop matching calculations in EQCD and QCD, sothat the unphysical (classical) UV behaviour of EQCD is replaced by its proper quantum QCD coun-terpart. I will show how lattice and perturbative EQCD are in excellent agreement in the UV andI will discuss the numerical effect of the two-loop quantum QCD contribution, with an outlook onthe effect on medium-induced radiation rates.The talk is based on G.D. Moore, N. Schlusser 2009.06614, J. Ghiglieri, G.D. Moore, P. Schicho, N.Schlusser 2112.01407, J. Ghiglieri, P. Schicho, N. Schlusser, E. Weitz, in preparatio
Azimuthal correlations of heavy-flavor hadron decay electrons with charged particles in pp and p–Pb collisions at = 5.02 TeV
No full textInternational audienceThe azimuthal () correlation distributions between heavy-flavor decay electrons and associated charged particles are measured in pp and p–Pb collisions at TeV. Results are reported for electrons with transverse momentum and pseudorapidity . The associated charged particles are selected with transverse momentum , and relative pseudorapidity separation with the leading electron . The correlation measurements are performed to study and characterize the fragmentation and hadronization of heavy quarks. The correlation structures are fitted with a constant and two von Mises functions to obtain the baseline and the near- and away-side peaks, respectively. The results from p–Pb collisions are compared with those from pp collisions to study the effects of cold nuclear matter. In the measured trigger electron and associated particle kinematic regions, the two collision systems give consistent results. The distribution and the peak observables in pp and p–Pb collisions are compared with calculations from various Monte Carlo event generators
Joint cosmological and gravitational-wave population inference using dark sirens and galaxy catalogues
No full textInternational audienceIn the absence of numerous gravitational-wave detections with confirmed electromagnetic counterparts, the "dark siren" method has emerged as a leading technique of gravitational-wave cosmology. The method allows redshift information of such events to be inferred statistically from a catalogue of potential host galaxies. Due to selection effects, dark siren analyses necessarily depend on the mass distribution of compact objects and the evolution of their merger rate with redshift. Informative priors on these quantities will impact the inferred posterior constraints on the Hubble constant (). It is thus crucial to vary these unknown distributions during an inference. This was not possible in earlier analyses due to the high computational cost, restricting them to either excluding galaxy catalogue information, or fixing the gravitational-wave population mass distribution and risking introducing bias to the measurement. This paper introduces a significantly enhanced version of the Python package GWCOSMO, which allows joint estimation of cosmological and compact binary population parameters. This thereby ensures the analysis is now robust to a major source of potential bias. The gravitational-wave events from the Third Gravitational-Wave Transient Catalogue are reanalysed with the GLADE+ galaxy catalogue, and an updated, more reliable measurement of km s Mpc is found (maximum a posteriori probability and 68% highest density interval). This improved method will enable cosmological analyses with future gravitational-wave detections to make full use of the information available (both from galaxy catalogues and the compact binary population itself), leading to promising new independent bounds on the Hubble constant
Study of flavor dependence of the baryon-to-meson ratio in proton-proton collisions at TeV
No full textInternational audienceThe production cross sections of and hadrons originating from beauty-hadron decays (i.e. non-prompt) were measured for the first time at midrapidity () by the ALICE Collaboration in proton-proton collisions at a center-of-mass energy TeV. They are described within uncertainties by perturbative QCD calculations employing the fragmentation fractions of beauty quarks to baryons measured at forward rapidity by the LHCb Collaboration. The production cross section per unit of rapidity at midrapidity, estimated from these measurements, is b. The baryon-to-meson ratios are computed to investigate the hadronization mechanism of beauty quarks. The non-prompt production ratio has a similar trend to the one measured for the promptly produced charmed particles and to the p and ratios, suggesting a similar baryon-formation mechanism among light, strange, charm, and beauty hadrons. The -integrated non-prompt ratio is found to be significantly higher than the one measured in ee collisions
Hard parton dispersion in the quark-gluon plasma, non-perturbatively
No full textInternational audienceThe in-medium dispersion of hard partons, encoded in their so-called asymptotic mass, receives large non-perturbative contributions from classical gluons, i.e. soft gluons with large occupation numbers. Here, we discuss how the analytical properties of thermal amplitudes allow for a non-perturbative determination of the infrared classical contribution through lattice determinations in the dimensionally-reduced effective theory of hot QCD, EQCD. We show how these lattice determinations need to be complemented by perturbative two-loop matching calculations between EQCD and QCD, so that the unphysical (classical) ultraviolet behavior of EQCD is replaced by its proper quantum QCD counterpart. We show how lattice and perturbative EQCD are in good agreement in the UV and present an outlook on the two-loop quantum QCD contribution
The Design and Technology Development of the JUNO Central Detector
No full textInternational audienceThe Jiangmen Underground Neutrino Observatory (JUNO) is a large scale neutrino experiment with multiple physics goals including deter mining the neutrino mass hierarchy, the accurate measurement of neutrino oscillation parameters, the neutrino detection from the super nova, the Sun, and the Earth, etc. JUNO puts forward physically and technologically stringent requirements for its central detector (CD), including a large volume and target mass (20 kt liquid scintillator, LS), a high energy resolution (3% at 1 MeV), a high light transmittance, the largest possible photomultiplier (PMT) coverage, the lowest possible radioactive background, etc. The CD design, using a spherical acrylic vessel with a diameter of 35.4 m to contain the LS and a stainless steel structure to support the acrylic vessel and PMTs, was chosen and optimized. The acrylic vessel and the stainless steel structure will be immersed in pure water to shield the radioactive back ground and bear great buoyancy. The challenging requirements of the acrylic sphere have been achieved, such as a low intrinsic radioactivity and high transmittance of the manufactured acrylic panels, the tensile and compressive acrylic node design with embedded stainless steel pad, one-time polymerization for multiple bonding lines. Moreover, several technical challenges of the stainless steel structure have been solved: the production of low radioactivity stainless steel material, the deformation and precision control during production and assembly, the usage of high strength stainless steel rivet bolt and of high friction efficient linkage plate. Finally, the design of the ancillary equipment like the LS filling, overflowing and circulating system was done