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Measurement of inclusive dijet cross-sections in proton-proton collisions at TeV with the ATLAS detector
No full textInternational audienceInclusive dijet cross-sections have been measured in proton-proton collisions at a centre-of-mass energy of 13 TeV using data with an integrated luminosity of 140 fb, recorded by the ATLAS detector at the Large Hadron Collider during 2015-2018. Jets are identified using the anti- algorithm with a radius parameter of . The inclusive dijet double-differential cross-sections are measured first as a function of the invariant dijet mass and the half absolute rapidity separation between the two leading jets, , , and second as a function of the invariant dijet mass and the total longitudinal boost of the dijet system, , . The measured dijet system covers the invariant mass range from 240 GeV to almost 10 TeV, with dijet separation and dijet boost . The results are unfolded to the particle level and compared with state-of-the-art next-to-next-to-leading-order full colour perturbative QCD calculations, corrected for non-perturbative and electroweak effects
Search for heavy neutral leptons in B-meson decays
No full textInternational audienceA search for long-lived heavy neutral leptons produced in B-meson decays and decaying to a final state is performed with data collected by the LHCb experiment in proton-proton collisions at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of . The results are interpreted in both lepton-number-conserving and lepton-number-violating scenarios. No significant excess is observed. Constraints are placed on the squared mixing element to the active muon neutrino, under the assumption that couplings to other lepton flavours are negligible, in the mass range of - GeV
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
Multiple comparisons of point clouds acquired by a permanent LiDAR (PLS) to improve the reliability of a rockfall event catalogue
No full textInternational audienceThe ANR C2R-IA project (www.anrc2ria.fr) aims to develop reliable decision-support tools for the dynamic management of rockfall hazard. Its goal is to understand how meteorological forcing influences rockfall occurrence and to anticipate temporary increases in hazard in order to implement risk reduction measures. To this end, a predictive model of rockfall occurrence as a function of meteorological conditions is being developed using artificial intelligence tools (neural network training), which requires a comprehensive and well-labelled dataset. Several monitoring instruments have been deployed at the Saint-Eynard site (Grenoble, France). Among them, a permanent LiDAR scanner (PLS) acquires point clouds continuously, with one acquisition per hour, providing high temporal resolution representative of what could be used for operational monitoring or crisis management. An automated data-processing workflow has been developed in Python. It is based on a pairwise comparison of the clouds (Manceau et al., 2025) and includes the alignment of successive point clouds, filtering of points outside the cliff area, change detection using M3C2 distances computation, clustering with DBSCAN, and volume quantification of rockfalls using alphashapes. This well-structured processing has significantly reduced the detection threshold, identifying relief change of only 10 cm deep (compared to 40 cm previously; Le Roy et al, 2020) and 10 liters in volume, while the scanner is located approximately 1 km from the cliff. Depending on acquisition quality, the effective temporal resolution of detected rockfall events may range from one hour to several days. Combining relief-change detections with simultaneously deployed seismic monitoring should further refine event timing. The completeness of the event catalogue has therefore improved, increasing from fewer than 10 detected rockfalls per month to around 30. However, some false positives remain, mainly related to recurring artifacts despite preprocessing. To mitigate these errors, the previous pairwise comparison of the clouds has been refined to a multiple point-cloud comparison strategy, enabling the tracking of the temporal persistence of changes. This allows distinguishing changes corresponding to real rockfalls, which persist over time, from transient artifacts. This improvement leads to a more reliable and complete rockfall event database. It includes block shape ratios, identified failure mechanisms, and free-fall heights under overhanging sections, providing a suitable basis for future fusion with seismic data.Manceau, L., Chanut, M.-A., Levy, C., Dewez, T., and Amitrano, D.: Enhancing Rockfall Detection Using Permanent LiDAR Scanner (PLS) Data and Automated Workflows at St. Eynard Cliff (Grenoble, France), EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-6312, https://doi.org/10.5194/egusphere-egu25-6312 Le Roy, G., Helmstetter, A., Amitrano, D., Guyoton, F., & Le Roux-Mallouf, R. (2019). Seismic analysis of the detachment and impact phases of a rockfall and application for estimating rockfall volume and free-fall height. Journal of Geophysical Research: Earth Surface, 124, 2602-2622. https://doi.org/10.1029/2019JF00499
A wide-field X-ray search for the Geminga pulsar halo with SRG/ART-XC
No full textInternational audienceSearches for the putative large-scale X-ray halo around the Geminga pulsar have been extensively performed using various narrow field-of-view X-ray telescopes. In this paper, we present wide-field scanning observation of Geminga with SRG/ART-XC. Our X-ray analysis provides, for the first time, direct imaging of a region in the keV energy band, comparable in extent to the expected Geminga emission. The ART-XC observation provides a highly uniform sky coverage without strong vignetting effects. The synchrotron X-ray halo flux was predicted using a physical model based on particle injection, diffusion, and cooling over the pulsar's lifetime, as well as the spectral and spatial properties of the synchrotron X-ray and inverse-Compton gamma-ray emissions. The model is tuned to reproduce existing multiwavelength data from X-ray upper limits and GeV to TeV gamma-ray observations. After accounting for the high particle background and its uncertainties, no significant emission is found in the assumed source region, and X-ray flux upper limits are derived. These limits are less constraining by up to a factor of three with respect to existing results obtained with narrow field-of-view telescopes and longer exposure times. Nonetheless, we place direct and independent constraints on Geminga's ambient magnetic field strength, which are compatible with other studies. Our methodology, including simulation for longer observation times, is applied for the first time to the wide field-of-view search for pulsar halos. Using extensive simulations, we also show that a 68% probability of detecting the Geminga pulsar halo can be achieved with a 20-day SRG/ART-XC exposure for a 3 magnetic field
Increasing prevalence of warm monomictic lakes in France over six decades under climate change
No full textInternational audienceThis study utilized temperature simulations from the Ottosson-Kettle-Prats Lake Model and a modified Lewis classification to analyze temporal changes in mixing-regime dynamics, temperature, density gradients, and meteorological indicators in 170 French lakes between 1959 and 1988 and 1989-2019. In the initial period, 55%, 30% and 15% of lakes were classified as warm monomictic, polymictic and dimictic respectively, with 57% of lakes experiencing anomalous regimes. Notably, 6% of the lakes, all at low altitudes (< 800 m a.s.l.) and located in central and north-eastern France shifted from dimictic to warm monomictic between the two periods, representing 77% of all low-altitude dimictic lakes. In 1989-2019, these lakes experienced a warmer climate with annual air temperatures increasing by an average of 0.19 °C/dec across all lakes, with an annual epilimnion warming averaging 0.25 °C/dec compared to 0.2 °C/dec for non-shifting lakes. Additionally, they became more stable and had the greatest density gradient change, averaging 0.07 kg/m³ between 1989 and 2019 and 1959-1988. In contrast, high-altitude lakes remained dimictic, showing an annual epilimnion warming averaging 0.19 °C/dec and a particular winter solar radiation decrease averaging -6.96 W/m 2 /dec in 1989-2019. Further, they did not show significant changes in average density gradients between the two periods. Our findings provide new insights into the mixing-regime dynamics of French lakes over the past six decades. This research is crucial for understanding the ecological impacts of physical alterations and for guiding management strategies under climate change. In the future, we expect less mixing in dimictic lakes, especially those at low altitudes
Windows, fans, and solar shadings during summer and heatwave: Occupant behavior and potential for improvement in heat-mitigation practices
No full textInternational audienceOccupant behavior during summer and heatwaves has a strong impact on overheating in free-running residential buildings. Yet, the use of windows, solar shadings, and fans remains poorly studied. This study addresses this gap through the largest monitoring campaign of its kind in France on this topic, covering 76 dwellings across three regions in summer 2023. Window states, solar shading positions, fan use, and indoor and outdoor conditions were systematically monitored for four months. Behaviors were analyzed individually and in combination to better understand real behavior in this context and assess the adoption of heat-mitigation practices and their potential for improvement.Results reveal substantial diversity across dwellings and through summer periods. General tendencies are consistent with previous datasets from other countries and contexts, with two main differences. Fan use is over four times lower at similar indoor and outdoor conditions, likely reflecting cultural factors. Unlike air-conditioned buildings, no cutoff temperature is observed for night-time window opening, reflecting a distinct night cooling strategy. During heatwaves, adaptive behaviors are adopted, yet the potential for improvement averages 40 % and ranges from 15 % to 75 % across dwellings. The largest potential of improvement lies in closing windows during the day when outdoor temperatures exceed indoor ones, whereas heat-mitigation practices are more consistently adopted at night.These findings provide a foundation for developing needed, more realistic occupant behavior models for French residential context during summer and heatwave. These results provide guidance for future awareness campaigns promoting passive heat-mitigation practices of occupants, emphasizing their importance
Digging deeper: deep joint species distribution modeling reveals environmental drivers of Earthworm Communities
No full textInternational audienceEarthworms are key drivers of soil function, influencing organic matter turnover, nutrient cycling, and soil structure. Understanding the environmental controls on their distribution is essential for predicting the impacts of land use and climate change on soil ecosystems. While local studies have identified abiotic drivers of earthworm communities, broad-scale spatial patterns remain underexplored. We developed a multi-species, multi-task deep learning model to jointly predict the distribution of 77 earthworm species across metropolitan France, using historical (1960–1970) and contemporary (1990–2020) records. The model integrates climate, soil, and land cover variables to estimate habitat suitability. We applied SHapley Additive exPlanations (SHAP) to identify key environmental drivers and used species clustering to reveal ecological response groups. The joint model achieved high predictive performance (TSS >0.7) and improved predictions for rare species compared to traditional species distribution models. Shared feature extraction across species allowed for more robust identification of common and contrasting environmental responses. Precipitation variability, temperature seasonality, and land cover emerged as dominant predictors of earthworm distribution but differed in ranking across species and functional groups. Species clustering into response groups to climatic, land use and soil revealed distinct ecological strategies including a gradient of sensitivity to precipitation seasonality, differential habitat preferences in terms of vegetation cover and wetness and trade-offs between soil acidity and organic matter quality. Our study advances both the methodological and ecological understanding of soil biodiversity. We demonstrate the utility of interpretable deep learning approaches for large-scale soil fauna modeling and provide new insights into earthworm habitat specialization. These findings highlight land cover and seasonal climate variability as efficient proxies for soil biodiversity, providing actionable indicators for global monitoring initiatives and helping to identify habitat requirements of earthworm species to guide emerging earthworm conservation strategies in the face of global environmental change
Precision cross-sections for advancing cosmic-ray physics and other applications: a comprehensive programme for the next decade
No full textInternational audienceCosmic-ray physics in the GeV-to-TeV energy range has entered a precision era thanks to recent data from space-based experiments. However, the poor knowledge of nuclear reactions, in particular for the production of antimatter and secondary nuclei, limits the information that can be extracted from these data, such as source properties, transport in the Galaxy and indirect searches for particle dark matter. The Cross-Section for Cosmic Rays at CERN workshop series has addressed the challenges encountered in the interpretation of high-precision cosmic-ray data, with the goal of strengthening emergent synergies and taking advantage of the complementarity and know-how in different communities, from theoretical and experimental astroparticle physics to high-energy and nuclear physics. In this paper, we present the outcomes of the third edition of the workshop that took place in 2024. We present the current state of cosmic-ray experiments and their perspectives, and provide a detailed road map to close the most urgent gaps in cross-section data, in order to efficiently progress on many open physics cases, which are motivated in the paper. Finally, with the aim of being as exhaustive as possible, this report touches several other fields -- such as cosmogenic studies, space radiation protection and hadrontherapy -- where overlapping and specific new cross-section measurements, as well as nuclear code improvement and benchmarking efforts, are also needed. We also briefly highlight further synergies between astroparticle and high-energy physics on the question of cross-sections
Validation of a lipopetide approach to a Safe-and-Sustainable-by-Design strategy on nano-TiO2 UV filters
No full textInternational audienceTitanium dioxide (TiO2) nanoparticles are well suited for cosmetics and polymer films because they efficiently absorb UV light while remaining transparent to visible light. Their widespread use requires strategies for managing potential human and environmental risks. Implementing the Safe and Sustainable by Design (SSbD) methodology to advanced chemicals and materials is a major global challenge and a concept that is included in several EU research projects. This study employed a SSbD strategy by functionalizing the surface of TiO2 nanoparticles with a lipopeptide-based biosurfactant (Sodium Surfactin, SS). A colloidal heterocoagulation approach was used to produce SS-modified TiO2 nanoparticles. Different design options (TiO2 source, order of addition, TiO2/SS weight ratio) were investigated, and the properties were compared by measuring the UV filtering capability, photoreactivity, dustiness index, biological and ecotoxicological endpoints. This allowed us to estimate the safety and sustainability profile in agreement with the steps suggested by the JRC SSbD framework. The lipopeptide-based coating was essential for managing UV light-induced photoactivity and significantly lowering both in vitro cytotoxicity and ecotoxicity while simultaneously enhancing photostability when applied in cosmetic formulations. These results demonstrate that a colloidal process, which can be easily scaled up for industrial purposes, is a promising and exploitable SSbD strategy for the design and implementation of nano-TiO2 based UV filters