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Reconstruction of atmospheric neutrinos in DUNE's horizontal-drift far-detector module
No full textInternational audienceThis paper reports on the capabilities in reconstructing and identifying atmospheric neutrino interactions in one of the Deep Underground Neutrino Experiment's (DUNE) far detector modules, a liquid argon time projection chamber (LArTPC) with horizontal drift (FD-HD) of ionization electrons. The reconstruction is based upon the workflow developed for DUNE's long-baseline oscillation analysis, with some necessary machine-learning models' retraining and the addition of features relevant only to atmospheric neutrinos such as the neutrino direction reconstruction. Where relevant, the impact of the detection of the charged particles of the hadronic system is emphasized, and comparisons are carried out between the case when lepton-only information is considered in the reconstruction (as is the case for many neutrino oscillation experiments), versus when all particles identified in the LArTPC were included. Three neutrino direction reconstruction methods have been developed and studied for the atmospheric analyses: using lepton-only information, using all reconstructed particles, and using only correlations from reconstructed hits. The results indicate that incorporating more than just lepton information significantly improves the resolution of both neutrino direction and energy reconstruction. The angle reconstruction algorithms developed in this work result in no strong dependence on particle direction for reconstruction efficiencies or neutrino flavor identification. This comprehensive review of the reconstruction of atmospheric neutrinos in DUNE's FD-HD LArTPC is the first step towards developing a first neutrino oscillation sensitivity analysis, which will ready DUNE for its first measurements
First European Interlaboratory Ring Test Study to Detect DNA of Crayfish and the Crayfish Plague Pathogen From Water Samples
No full textInternational audienceIn recent years, European countries have intensified efforts to control or limit the spread of invasive freshwater crayfish and the crayfish plague pathogen Aphanomyces astaci , while working to conserve native species such as the noble crayfish ( Astacus astacus ). Although crayfish shed relatively low amounts of DNA into their environment, environmental DNA (eDNA) approaches have proven effective for detecting their presence. A range of protocols and equipment is currently used in eDNA‐based monitoring of freshwater crayfish. To evaluate how methodological variation influences detection accuracy, we conducted the first European interlaboratory ring test using eDNA to detect A. astacus , the invasive signal crayfish Pacifastacus leniusculus , a chronic carrier of A. astaci , and the pathogen itself. The aim is to harmonize monitoring methods for crayfish and disease surveillance across laboratories. Eleven teams from thirteen European countries participated, each using its own equipment and protocols to collect and filter water from indoor tanks and outdoor ponds where the presence of A. astacus and P. leniusculus had been experimentally manipulated, as well as from a natural lake containing a P. leniusculus population. The resulting samples were analyzed in each team's laboratory. Despite methodological differences, all teams successfully detected DNA from both crayfish species in indoor tanks (3–10 crayfish/m 3 ). However, detection accuracy declined in outdoor ponds where crayfish density was an order of magnitude lower (0.32 crayfish/m 3 ). Detection was most variable for A. astaci , likely due to its very low prevalence in the host stock. Our study demonstrates the challenges of achieving consistent eDNA results across laboratories and highlights the importance of interlaboratory comparisons. It also underscores the need to identify sources of variability and error, an essential step toward developing robust and standardized protocols. This multinational intercalibration and exchange of knowledge improved methodology and enhanced reliability in crayfish detection
Finite-resolution measurement induces topological curvature defects in spacetime
No full textWe show that regularizing (2 + 1)-dimensional Minkowski spacetime with a finite-resolution Gaussian probe, analogous to Weyl-Heisenberg (Gabor) signal analysis and related quantization, induces a curved geometry with a topological defect. The regularized metric replaces r 2 by r 2 + σ 2 in the angular part, where σ is the resolution scale from the width of the Gaussian probe. The resulting Gaussian curvature integrates to -2π, independently of σ, and including the boundary contribution, yields Euler characteristic χ = 0, corresponding to a punctured plane. This curvature defines an effective stress-energy source with total energy E eff = -1/(4G), universal and σ-independent. Spatial slices embed isometrically as helicoids, and geodesics exhibit a characteristic swirling motion. These results show that finite spatial resolution measurement does not merely smooth singularities but imprints topological defects with fixed physical consequences, suggesting that observational limitations fundamentally shape spacetime geometry. We show how our Gabor regularisation is extendable to (3 + 1) Minkowski space-time
Measurement of the Higgs boson total decay width using the H WW e decay channel in proton-proton collisions at = 13 TeV
No full textInternational audienceThe Higgs boson (H) decay width is determined from the ratio of off- and on-shell production of H WW e using proton-proton collision data corresponding to an integrated luminosity of 138 fb collected at = 13 TeV by the CMS experiment at the LHC. The off-shell signal strength is measured as = 1.2. The Higgs boson total decay width is = 3.9 MeV, in agreement with the standard model prediction. The uncertainty in this result represents a factor of three improvement over the previous CMS result in this decay channel
Search for planetary-mass ultra-compact binaries using data from the first part of the LIGO--Virgo--KAGRA fourth observing run
No full textInternational audienceWe present a search for gravitational waves from inspiraling, planetary-mass ultra-compact binaries using data from the first part of the fourth observing run of LIGO, Virgo and KAGRA. Finding no evidence of such systems, we determine the maximum distance reach for such objects and their merger rate densities, independently of how they could have formed. Then, we identify classes of primordial black-hole mass distributions for which these rate limits can be translated into relevant constraints on the mass distribution of primordial black holes, assuming that they compose all of dark matter, in the mass range . Our constraints are consistent with existing microlensing results in the planetary-mass range, and provide a complementary probe to sub-solar mass objects
Energy-Dependent Shifts of Medium-Scale Anisotropies in Very-High-Energy Cosmic Rays Observed by LHAASO-KM2A
No full textInternational audienceSmall deviations from isotropy in the arrival directions of Galactic cosmic rays serve as a unique probe of the local magnetic environment. In this Letter, we report observations of medium-scale anisotropies (MSA) at energies above 10 TeV using the LHAASO-KM2A array. Our analysis identifies four regions of excess and four regions of deficit, each spanning angular scales of approximately ten degrees. Crucially, we detect significant energy-dependent shifts in the centroids of two excess regions: Region B and the newly identified Region . We also characterize the energy evolution of the fractional relative intensity across both excess and deficit regions. These findings imply that the observed anisotropies are shaped by the specific realization of the local turbulent magnetic field within the cosmic ray scattering length. Such energy-dependent behaviors impose strict constraints on local turbulence models and cosmic ray propagation theories
Constraints on Solar Reflected Dark Matter from a combined analysis of XENON1T and XENONnT data
No full textInternational audienceWe report on a search for sub-GeV dark matter upscattered via the solar reflection mechanism in the heavy mediator scenario. Under the Standard Halo Model, keV to MeV dark matter produces nuclear recoils with energies below the detection threshold of liquid xenon time projection chambers. We enhance sensitivity to low-mass dark matter by considering dark matter-electron scattering, employing dedicated event selections to reduce the detection threshold, and exploiting the additional kinetic energy imparted to the dark matter particle by solar upscattering. Using XENON1T ionization-only and XENONnT low-energy electronic recoil datasets, we exclude previously unconstrained DM-electron scattering cross section for masses between and , and between and , reaching a minimum of for a mass of at 90% confidence level
Blind Deconvolution in Astronomy: How Does a Standalone U-Net Perform?
No full textInternational audienceAims: This study investigates whether a U-Net architecture can perform standalone end-to-end blind deconvolution of astronomical images without any prior knowledge of the Point Spread Function (PSF) or noise characteristics. Our goal is to evaluate its performance against the number of training images, classical Tikhonov deconvolution and to assess its generalization capability under varying seeing conditions and noise levels. Methods: Realistic astronomical observations are simulated using the GalSim toolkit, incorporating random transformations, PSF convolution (accounting for both optical and atmospheric effects), and Gaussian white noise. A U-Net model is trained using a Mean Square Error (MSE) loss function on datasets of varying sizes, up to 40,000 images of size 48x48 from the COSMOS Real Galaxy Dataset. Performance is evaluated using PSNR, SSIM, and cosine similarity metrics, with the latter employed in a two-model framework to assess solution stability. Results: The U-Net model demonstrates effectiveness in blind deconvolution, with performance improving consistently as the training dataset size increases, saturating beyond 5,000 images. Cosine similarity analysis reveals convergence between independently trained models, indicating stable solutions. Remarkably, the U-Net outperforms the oracle-like Tikhonov method in challenging conditions (low PSNR/medium SSIM). The model also generalizes well to unseen seeing and noise conditions, although optimal performance is achieved when training parameters include validation conditions. Experiments on synthetic images further support the hypothesis that the U-Net learns a geometry-adaptive harmonic basis, akin to sparse representations observed in denoising tasks. These results align with recent mathematical insights into its adaptive learning capabilities
Characterization of CRYO ASIC for charge readout in the nEXO experiment
No full textInternational audiencenEXO is a proposed next-generation experiment searching for the neutrinoless double beta decay of Xe using a tonne-scale liquid xenon (LXe) time projection chamber (TPC). To image the ionization signals from events in the liquid xenon, the detector will employ metallized fused-silica charge collection tiles instrumented with cryogenic application-specific integrated circuits (ASICs), referred to as CRYO ASIC, which are designed to operate directly in LXe to minimize input capacitance and pick-up noise. Here we present the performance of the CRYO ASIC mounted on an auxiliary printed circuit board and evaluated both in a cryogenic environmental chamber and in a dedicated LXe test stand. We demonstrate that the ASICs achieve the desired performance at liquid xenon temperatures, showing a gain stability better than 0.2% over 24-hour operation and reliable in-situ calibration using an on-chip pulser. In the LXe test stand, we show that boiling caused by the chip heat dissipation can be mitigated by operating the system above ~0.1 MPa. The in-LXe noise measured agrees with simulation, which indicates it the design requirement can be satisfied. These results establish CRYO ASIC as a viable low-noise in-LXe charge readout solution for nEXO
A new path to constrain the expansion history of the Universe in future spectroscopic galaxy surveys
No full textInternational audienceThe current tension between early- and late-Universe measurements of the Hubble constant (), along with the still elusive nature of dark matter and dark energy, calls for model-independent probes of the Universe's expansion history. The cosmic chronometers (CC) method offers a unique opportunity to directly measure the Hubble parameter without relying on any cosmological model assumptions or integrated distance measurements. Despite its potential, this technique remains statistics-limited: no current survey is optimized to detect large samples of CC, restricting the precision on to 20% at intermediate redshifts. Here, we investigate the opportunities that a next-generation spectroscopic facility could offer to CC studies, providing an estimate of the accuracy achievable on the reconstruction of the Hubble parameter in redshift. We demonstrate that with such a facility, it will be possible to derive constraints on key cosmological parameters, assessing the impact that such improvements would have on our understanding of the expansion history of the Universe and on current cosmological tensions