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Fusion of C+Si at deep sub-barrier energies
No full textInternational audienceThe existence of fusion hindrance is not well established in light heavy-ion systems. Studying slightly heavier cases allows extrapolating the trend to light systems of astrophysical interest. Fusion of 12C + 28Si has been measured down to deep sub-barrier energies, using 28Si beams from the XTU Tandem accelerator of LNL on thin 12C targets. The fusion-evaporation residues were detected by a detector telescope following an electrostatic beam separator, and coincidences between the gamma-ray array AGATA and segmented silicon detectors DSSD were performed, where the evaporated light charged particles were identified by pulse shape analysis. Fusion cross sections have been obtained in the wide range 150 mb-42 nb. Coupled-channel (CC) calculations using a Woods-Saxon potential reproduce the data above 0.1 mb. Below that, hindrance shows up and the CC results overestimate the cross sections which get close to the one-dimensional potential tunnelling limit. This suggests that the coupling strengths gradually vanish, as predicted by the adiabatic model. The hindrance threshold follows a recently updated phenomenological systematics
Euclid Quick Data Release (Q1): From spectrograms to spectra: the SIR spectroscopic Processing Function
No full textInternational audienceThe Euclid space mission aims to investigate the nature of dark energy and dark matter by mapping the large-scale structure of the Universe. A key component of Euclid's observational strategy is slitless spectroscopy, conducted using the Near Infrared Spectrometer and Photometer (NISP). This technique enables the acquisition of large-scale spectroscopic data without the need for targeted apertures, allowing precise redshift measurements for millions of galaxies. These data are essential for Euclid's core science objectives, including the study of cosmic acceleration and the evolution of galaxy clustering, as well as enabling many non-cosmological investigations. This study presents the SIR processing function (PF), which is responsible for processing slitless spectroscopic data. The objective is to generate science-grade fully-calibrated one-dimensional spectra, ensuring high-quality spectroscopic data. The processing function relies on a source catalogue generated from photometric data, effectively corrects detector effects, subtracts cross-contaminations, minimizes self-contamination, calibrates wavelength and flux, and produces reliable spectra for later scientific use. The first Quick Data Release (Q1) of Euclid's spectroscopic data provides approximately three million validated spectra for sources observed in the red-grism mode from a selected portion of the Euclid Wide Survey. We find that wavelength accuracy and measured resolving power are within requirements, thanks to the excellent optical quality of the instrument. The SIR PF represents a significant step in processing slitless spectroscopic data for the Euclid mission. As the survey progresses, continued refinements and additional features will enhance its capabilities, supporting high-precision cosmological and astrophysical measurements
Extraction of Dihadron Fragmentation Functions at NNLO with and without Neural Networks
No full textInternational audienceWe present a new extraction of unpolarized Dihadron Fragmentation Functions, which describe the probability density for an unpolarized parton to fragment into a pair. Our analysis is based on data from the BELLE collaboration. We improve on previous determinations in several key aspects: we employ state-of-the-art perturbative QCD calculations up to next-to-next-to-leading order (NNLO); we limit the use of Monte Carlo event generators to estimating the relative contributions of different flavors, a necessary input due to the limited flavor sensitivity of the available data; and, in addition to a traditional fit based on a physics-informed functional form, we explore a Neural Network parametrization. This latter approach paves the way for more robust and flexible determinations of Dihadron Fragmentation Functions using machine learning techniques
Flavor constraints from and at the LHC
No full textInternational audienceWe investigate the potential of associated Higgs and diboson production channels at the LHC (with ) to constrain flavor-physics operators. Within a general Effective Field Theory (EFT) framework, we derive the helicity amplitudes for these processes at high energies and identify the leading contributions from dimension-six operators involving different quark flavors. Using available LHC data, we show that these processes are sensitive to non-trivial flavor structures and provide complementary constraints to those from low-energy observables. We illustrate this synergy through an explicit comparison between our LHC bounds with electroweak precision data, and with flavor limits derived from charged-current pion and kaon decays. In particular, we show that our HL-LHC projections can probe viable EFT scenarios proposed to accommodate the discrepancies in the extraction of the Cabibbo angle
Immersive Environments
No full textInternational audienceImmersive environments present significant management opportunities for businesses, enabling innovative approaches toemployee engagement, customer interactions, and operational efficiency. Through the integration of virtual and augmented realitytechnologies, organizations can enhance training programs, improve workplace safety, and optimize operational support in sectorssuch as manufacturing and engineering. Additionally, immersive environments facilitate remote collaboration, talent acquisition,and the creation of engaging work environments, addressing the challenges of a competitive job market. Looking forward,advancements in technology and user experience will drive the widespread adoption of immersive environments, fosteringinterdisciplinary collaboration to create personalized and interactive experiences. As immersive technologies become moreaccessible and widespread, accompanied by supplementary tools and techniques, they hold immense potential to revolutionizeindustries beyond entertainment, including healthcare and education. The trajectory of immersive environments points towardscontinued growth, innovation, and enhanced human engagement across various sectors, signaling a transformative shift in howbusinesses operate and interact with their stakeholders. Also, we propose the holistic framework for immersive environments,comprising three interconnected elements: immersive technology, environment, and experiences. These elements collectively shapeand define the nature of immersive environments, influencing their creation, deployment, and impac
Photophysics of cu-loaded MIL-125(Ti)-NH₂: Unravelling the role of cu oxidation states through time-resolved spectroscopy and density functional theory
No full textInternational audienc
Spatial resolution studies with the BabyIAXO Micromegas prototype
No full textInternational audienceThe spatial resolution of the Micromegas prototype developed for the BabyIAXO experiment was evaluated using a low-energy X-ray beam at the SOLEIL synchrotron facility. BabyIAXO, currently under construction, aims to search for hypothetical solar axions. A key component of the experiment is a low-background X-ray detector with high efficiency in the 1-10 keV energy range and stringent background rejection capabilities. Achieving a spatial resolution on the order of, or better than, 1 mm is critical for accurately reconstructing signal shapes and positions, and for effectively discriminating between signal and background events. Therefore, a precise characterization of the detector's spatial resolution is essential to validate its suitability for the experiment. This study involved scanning the IAXO-D1 Micromegas detector under various beam energies, positions, and drift field configurations to evaluate their influence on spatial resolution. A resolution of approximately 100 m at 6 keV was achieved, confirming the strong potential of this technology for application in the final BabyIAXO setup
Search for heavy neutral leptons in decays of W bosons produced in 13 TeV collisions using prompt signatures in the ATLAS detector
No full textInternational audienceThe existence of right-handed neutrinos with Majorana masses below the electroweak scale could help address the origins of neutrino masses, the matter-antimatter asymmetry, and dark matter. In this paper, leptonic decays of W bosons from 140 fb of 13 TeV proton-proton collisions at the LHC, reconstructed in the ATLAS experiment, are used to search for heavy neutral leptons produced through their mixing with muon or electron neutrinos in a scenario with lepton number violation. The search is conducted using prompt leptonic decay signatures. The considered final states require two same-charge leptons or three leptons, while vetoing three-lepton same-flavour topologies. No significant excess over the expected Standard Model backgrounds is found, leading to constraints on the heavy neutral lepton's mixing with muon and electron neutrinos for heavy-neutral-lepton masses. The analysis excludes values above and values above in the full mass range of 8-65 GeV. The strongest constraints are placed on heavy-neutral-lepton masses in the range 15--30 GeV of and
A multitasking scheduling problem of emergency medical response in mass casualty incident
No full textInternational audienceMass casualty incidents caused by unpredictable and devastating disasters result in significant property loss and pose serious threats to human life. In such crises, the ethical priority of emergency responders is to save as many lives as possible, despite limited medical resources. Effective delivery of emergency medical services is crucial in managing life-threatening events. The severe shortage of medical support during these disasters requires each medical professional to treat multiple patients simultaneously. Additionally, professionals should also promote the overall effectiveness of treatment by preventing "tying" themselves to one patient. This research introduces a scheduling model that integrates multitasking into patient treatment plans. The model aims to minimize time-related objectives to ensure a rapid medical response in time-critical scenarios, allowing all patients to benefit from more efficient prioritization schemes. To proactively evaluate the proposed model and treatment plans without incurring actual risks, a comprehensive solution framework has been developed. This framework includes asymptotically optimal heuristics, a well-designed branch-and-bound algorithm for exact solutions, and an improved memetic algorithm. The results demonstrate the effectiveness and robustness of the framework across various problem scales. By analyzing the structures of various solutions, managers gain valuable insights that inform policy decisions and guide emergency response planning
Direction-of-Arrival Estimation of Coherent Sources with Leaky-Wave Antennas using Spatially Filtered Interpolation
No full textInternational audienceWith their frequency-beam scanning behavior, leaky-wave antennas (LWAs) are promisingsolutions to develop accurate and cost-effective direction-of-arrival (DoA) estimationsystems. However, DoA estimators such as MUSIC face challenges with coherent sourcesdue to the non-Vandermonde LWA steering matrix. Leveraging the unique radiation propertiesof LWAs, this paper first divides the entire field of view into several angular sectors,and then introduces a robust and accurate sectorized spatially-filtered interpolation (SFI)method to transform the LWA steering matrix into a Vandermonde matrix in each sectorwhile minimizing the issue of out-of-sector interference. The proposed method allowsthus the estimation of DoAs of coherent sources with LWAs. The simulation results showthat the DoAs of multiple coherent sources across the entire field-of-view, regardless theirangular sector, can be correctly estimated. The performance of the proposed method isshown be close to the Cramér-Rao Bound