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Constraining primordial non-Gaussianity from DESI DR1 quasars and Planck PR4 CMB Lensing
No full textInternational audienceWe present the first measurement of local-type primordial non-Gaussianity from the cross-correlation between million spectroscopically confirmed quasars from the first data release (DR1) of the Dark Energy Spectroscopic Instrument (DESI) and the Planck PR4 CMB lensing reconstructions. The analysis is performed in three tomographic redshift bins covering , covering a sky fraction of . We adopt a catalog-based pseudo- estimator and apply linear imaging weights validated on noiseless mocks. Compared to previous analyses using photometric quasar samples, our results benefit from the high purity of the DESI spectroscopic sample, the reduced noise of PR4 lensing, and the absence of excess large-scale power in the spectroscopic quasar auto-correlation. Fitting simultaneously for the non-Gaussianity parameter and the linear bias amplitude in each redshift bin, we obtain for a response parameter , and for . These results improve the constraints on by compared to the previous analysis based on the Legacy Imaging Survey DR9. Our results demonstrate the statistical power of DESI quasars for probing inflationary physics, and highlight the promise of future DESI data releases
Looking for observational signatures of early binary black hole systems
No full textInternational audienceContext. A lot of recent studies have focused on the observables associated with near merger binary black-holes (BBHs) embedded in a circumbinary disk (CBD) but we still we lack knowledge of observables of BBHs in their early stage. In that stage the separation between the two black holes is so large that both black holes could potentially retain their individual accretion disk existing before the creation of the BBH. For such early BBH systems, it is interesting to look for observables originating in those individual disks whose structure is likely to differ from mini-disks often observed in simulations of later stages of BBHs. Aims. In a companion paper we presented a set of hydrodynamical simulations of an individual disk surrounding a primary black hole while being impacted by the presence of a secondary black-hole in an early BBH system, leading to the creation of three well-known characteristic features in the disk's structure. Here we explore the imprints of these three features on the observables associated with the thermal emission of the pre-existing black hole disk. The aim is two-fold, first to see which observables are best suited for detecting those early systems and, secondly, what could be extrapolated about these systems from observations. Methods. We used general relativistic ray-tracing in order to produce synthetic observations of the thermal emission emitted by early BBHs with different mass ratio and separations in order to search for distinctive observational features of early systems. Results. We found that in the case of early BBH with pre-existing disk(s) a necessary, although not unique, observational feature is the truncation of their disk(s). Conclusions. Such observable could be used for automated search of potential BBHs and discriminate some existing candidates
Measurement of the (p, α) reaction cross-section on natural lithium for production of high-energy α beam
No full textInternational audienceDouble differential cross-section values for the (p, α) reaction on natural lithium were determined for incident proton energies between 20 MeV and 25 MeV at emission angles between 15° and 55°. A distinct peak corresponding to high-energy α particles was observed in the spectra and the integrated differential cross-section over this peak was evaluated. This cross-section exhibits an angular dependence with a maximum around 45°, as well as an energy dependence where lower proton beam energies result in higher cross-section values. Our results are in good agreement with previous experimental data reported in the literature
Strongly interacting matter in extreme magnetic fields
No full textInternational audienceMagnetic fields are ubiquitous across different physical systems of current interest; from the early Universe, compact astrophysical objects and heavy-ion collisions to condensed matter systems. A proper treatment of the effects produced by magnetic fields during the dynamical evolution of these systems, can help to understand observables that otherwise show a puzzling behavior. Furthermore, when these fields are comparable to or stronger than Λ_QCD, they serve as excellent probes to help elucidate the physics of strongly interacting matter under extreme conditions of temperature and density. In this work we provide a comprehensive review of recent developments on the description of QED and QCD systems where magnetic field driven effects are important. These include the modification of meson static properties such as masses and form factors, the chiral magnetic effect, the description of anomalous transport coefficients, superconductivity in extreme magnetic fields, the properties of neutron stars, the evolution of heavy-ion collisions, as well as effects on the QCD phase diagram. We describe recent theory and phenomenological developments using effective models as well as LQCD methods. The work represents a state-of-the-art review of the field, motivated by presentations and discussions during the "Workshop on Strongly Interacting Matter in Strong Electromagnetic Fields" that took place in the European Centre for Theoretical Studies in Nuclear Physics and Related Areas (ECT*) in the city of Trento, Italy, September 25-29, 2023
Detection efficiency and spatial resolution of Monolithic Active Pixel Sensors bent to different radii
No full textInternational audienceBent monolithic active pixel sensors are the basis for the planned fully cylindrical ultra low material budget tracking detector ITS3 of the ALICE experiment. This paper presents results from testbeam campaigns using high-energy particles to verify the performance of 50 um thick bent ALPIDE chips in terms of efficiency and spatial resolution. The sensors were bent to radii of 18, 24 and 30 mm, slightly smaller than the foreseen bending radii of the future ALICE ITS3 layers. An efficiency larger than and a spatial resolution of approximately 5 um, in line with the nominal operation of flat ALPIDE sensors, is obtained at nominal operating conditions. These values are found to be independent of the bending radius and thus constitute an additional milestone in the demonstration of the feasibility of the planned ITS3 detector. In addition, a special geometry in which the beam particles graze the chip and traverse it laterally over distances of up to 3 mm is investigated
Observation of production in collisions at = 13 TeV with the ATLAS detector and constraints on anomalous quartic gauge-boson couplings
No full textInternational audienceThis Letter reports the observation of triboson production in 140 fb of data collected by the ATLAS detector from proton-proton collisions at a centre-of-mass energy of = 13 TeV at the LHC. Events with an opposite-charge pair, a high transverse-momentum photon, and significant missing transverse momentum are considered. The observed (expected) significance of the signal is 5.9 (6.0) standard deviations. The measured fiducial cross-section, defined for the final state is 6.2 0.8 (stat.) 0.6 (sys.) fb, in good agreement with the Standard Model prediction of 6.1 fb. Constraints on the Wilson coefficients of 13 dimension-8 operators describing physics beyond the Standard Model through anomalous quartic gauge-boson couplings are derived using the effective field theory framework
Dynamics of quantized vortices under quasi-periodic boundary conditions
No full textInternational audienceThe Gross-Pitaevskii equation is widely used for vortex dynamics, but finite domains with hard walls or confining potentials distort bulk behavior through vortex-image effects or induced flows. Periodic boundaries reduce wall artifacts yet cannot realize finite net vorticity because of topological obstruction, so bulk simulations with non-zero circulation are typically unavailable. Hence, we impose quasi-periodic boundary conditions that keep the superfluid's density periodic while enforcing phase windings consistent with a net prescribed total vorticity. This setting conserves the net number of vortices and enables long-time tracking of vortex trajectories in settings that finite containers cannot capture. This allows us to study vortex depinning and nucleation leading to the creation of Kármán vortex streets and the creation of perfectly periodic vortex arrays. The framework also provides a toy model for studying vortex dynamics in the bulk of neutron stars, free of possible limitations induced by confining potentials
Implementation of the Martini-Ericson-Chanfray-Marteau RPA-based (anti)neutrino cross-section model in the GENIE neutrino event generator
No full textInternational audienceWe discuss the first implementation of the Martini-Ericson-Chanfray-Marteau RPA-based (anti)neutrino cross-section model for quasielastic (1p1h) and multinucleon (2p2h and 3p3h) excitations in the widely used GENIE neutrino event generator. Validation steps are presented, in particular, through direct comparisons of GENIE cross section output with original calculations performed by the authors of the model. Predictions for C, O and Ar are compared with some available T2K and MicroBooNE experimental measurements showing a reasonable agreement
Characterization of the Electronic Noise in the Readout of Resistive Micromegas in the High-Angle Time Projection Chambers of the T2K Experiment
No full textInternational audienceThe two high-angle Time Projection Chambers of the T2K experiment are equipped with a new readout system based on resistive Micromegas detector technology, and utilize custom-made electronics based on AFTER chips for signal processing. This study analyzes and characterizes the electronic noise of the detector readout chain to develop a comprehensive noise model. The model enables the generation of Monte Carlo simulations to investigate systematic effects in signal processing. The analysis is based on data collected from 32 resistive Micromegas detectors, recorded without zero suppression. All detectors exhibit a quasi-identical and time-stable noise level. The developed analytical model accurately describes the observed noise, and derived Monte Carlo simulations show excellent agreement with experimental data
Measurements of the inclusive W and Z boson production cross sections and their ratios in proton-proton collisions at = 13.6 TeV
No full textInternational audienceMeasurements are presented of the W and Z boson production cross sections in proton-proton collisions at a center-of-mass energy of 13.6 TeV. Data collected in 2022 and corresponding to an integrated luminosity of 5.01 fb with one or two identified muons in the final state are analyzed. The results for the products of total inclusive cross sections and branching fractions for muonic decays of W and Z bosons are 11.93 0.08 (syst) 0.17 (lumi) (acc) nb for W boson production, 8.86 0.06 (syst) 0.12 (lumi) (acc) nb for W boson production, and 2.021 0.009 (syst) 0.028 (lumi) (acc) nb for the Z boson production in the dimuon mass range of 60-120 GeV, all with negligible statistical uncertainties. Furthermore, the corresponding fiducial cross sections, as well as cross section ratios for both fiducial and total phase space, are provided. The ratios include charge-separated results for W boson production (W and W) and the sum of the two contributions (W), each relative to the measured Z boson production cross section. Additionally, the ratio of the measured cross sections for W and W boson production is reported. All measurements are in agreement with theoretical predictions, calculated at next-to-next-to-leading order accuracy in quantum chromodynamics