Search Results (859)

Future $e^{+}{e}^{-}$ colliders are expected to play a fundamental role in measuring Standard Model (SM) parameters with unprecedented precision and in probing physics beyond the SM (BSM). This study investigates two-particle angular correlation distributions involving final-state SM charged hadrons. Unexpected correlation structures in these distributions is considered to be a hint for new physics perturbing the QCD partonic cascade and thereby modifying azimuthal and (pseudo)rapidity correlations. Using Pythia8 Monte Carlo generator and fast simulation, including selection cuts and detector effects, we study potential structures in the two-particle angular correlation function. We adopt the QCD-like Hidden Valley (HV) scenario as implemented in Pythia8 generator, with relatively light HV v-quarks (below about 100 GeV), to illustrate the potential of this method. Full article

In recent years, 3D pixel sensors have been a topic of increasing interest within the High Energy Physics community. Due to their inherent radiation hardness, demonstrated up to a fluence of $3\times {10}^{16}$ 1 MeV equivalent neutrons per square centimeter, 3D pixel sensors have been used to equip the innermost tracking layers of the ATLAS and CMS detector upgrades at the High-Luminosity Large Hadron Collider. Additionally, the next generation of vertex detectors calls for precise measurement of charged particle timing at the pixel level. Owing to their fast response times, 3D sensors present themselves as a viable technology for these challenging applications. Nevertheless, both radiation hardness and fast timing require 3D sensors to be operated with high bias voltages on the order of ∼150 V and beyond. Special attention should therefore be devoted to avoiding problems that could cause premature electrical breakdown, which could limit sensor performance. In this paper, TCAD simulations are used to gain deep insight into the impact of surface isolation layers (i.e., p-stop and p-spray) used by different vendors on the high-voltage tolerance of small-pitch 3D sensors. Results relevant to different geometrical configurations and irradiation scenarios are presented. The advantages and disadvantages of the available technologies are discussed, offering guidance for design optimization. Experimentalmeasurements from existing samples based on both isolation techniques show good agreement with simulated breakdown voltages, thereby validating the simulation approach. Full article

The dynamic aperture is an essential concept in circular particle accelerators, providing the extent of the phase space region where particle motion remains stable over multiple turns. The accurate prediction of the dynamic aperture is key to optimising performance in accelerators such as the CERN Large Hadron Collider and is crucial for designing future accelerators like the CERN Future Circular Hadron Collider. Traditional methods for computing the dynamic aperture are computationally demanding and involve extensive numerical simulations with numerous initial phase space conditions. In our recent work, we have devised surrogate models to predict the dynamic aperture boundary both efficiently and accurately. These models have been further refined by incorporating them into a novel active learning framework. This framework enhances performance through continual retraining and intelligent data generation based on informed sampling driven by error estimation. A critical attribute of this framework is the precise estimation of uncertainty in dynamic aperture predictions. In this study, we investigate various machine learning techniques for uncertainty estimation, including Monte Carlo dropout, bootstrap methods, and aleatory uncertainty quantification. We evaluated these approaches to determine the most effective method for reliable uncertainty estimation in dynamic aperture predictions using machine learning techniques. Full article

Based on the magnetic configuration of the China Astro-Torus-1 (CAT-1) levitated dipole device, this study investigated the confinement performance of common discharge gas ions under E × B transverse transport conditions induced by electric fields. By adjusting L-coil parameters to shift the inject location, it was found that when the loss boundary is in the outer weak-field region, most particles with large Larmor radii are lost after colliding with the wall, for particles with large pitch angles, the strongly anisotropic magnetic field causes particles across a broad range of energies to be lost through the X-point into the divertor. The study demonstrates that for particle kinetic energies between 100 and 300 eV, the CAT-1 device exhibits a loss cone angle θ_loss of approximately 58°, indicating favorable confinement performance. Full article

Multi-tethered spacecraft formation refers to a group of spacecraft that are connected by tethers. These spacecraft work together to perform tasks, such as encircling and capturing small celestial bodies. When the multi-tethered spacecraft formation is in the process of encircling and capturing small celestial bodies, there is a significant risk of the tethers colliding with the soil (or surface material) of the small celestial body. Such a collision can affect the trajectory of the small celestial body detector. To address this issue, a coupled dynamic model has been proposed. This model takes the interaction between the tethers and the soil of the small celestial body into account. The discrete element method is used to establish the asteroid soil model, and the multi-body-tethered spacecraft system is simplified into a two-spacecraft system. The detector model is established by using the dual quaternion, and the tether model is established by using the chain rod model combined with the finite element method. Finally, a multi-condition simulation test is carried out. The results show that the influence of tether–soil coupling on the trajectory of the detector is mainly as follows: the influence of tether–soil interaction on the trajectory of the detector is mainly reflected in the displacement of the detector along the axial direction of the tether. Full article

Belle II is a particle physics experiment working at an high luminosity collider within a hard irradiation environment. The Time-Of-Propagation detector, aimed at the charged particle identification, surrounds the Belle II tracking detector on the barrel part. This detector is composed by 16 modules, each module contains a finely fused silica bar, coupled to microchannel plate photomultiplier tube (MCP-PMT) photo-detectors and readout by high-speed electronics. The MCP-PMT lifetime at the nominal collider luminosity is about one year, this is due to the high photon background degrading the quantum efficiency of the photocathode. An alternative to these MCP-PMTs is multi-pixel photon counters (MPPC), known as silicon photomultipliers (SiPM). The SiPMs, in comparison to MCP-PMTs, have a lower cost, higher photon detection efficiency and are unaffected by the presence of a magnetic field, but also have a higher dark count rate that rapidly increases with the integrated neutron flux. The dark count rate can be mitigated by annealing the damaged devices and/or operating them at low temperatures. We tested SiPMs, with different dimensions and pixel sizes from different producers, to study their time resolution (the main constraint that has to satisfy the photon detector) and to understand their behavior and tolerance to radiation. For these studies we irradiated the devices to radiation up to $5\times {10}^{11}1$ MeV neutrons equivalent (neq) per cm² fluences; we also started studying the effect of annealing on dark count rates. We performed several measurements on these devices, on top of the dark count rate, at different conditions in terms of overvoltage and temperatures. These measurements are: IV-curves, amplitude spectra, time resolution. For the last two measurements we illuminated the devices with a picosecond pulsed laser at very low intensities (with a number of detected photons up to about twenty). We present results mainly on two types of SiPMs. A new SiPM prototype developed in collaboration with FBK with the aim of improving radiation hardness, is expected to be delivered in September 2025. Full article

In this paper, we analyze the application of an analytical gluon distribution based on double-asymptotic scaling to the photoproduction of vector mesons in coherent $pp$, $pA$, and $AA$ collisions at LHC energies, using the color dipole formalism. Predictions for the rapidity distribution are presented for ${\rho }^0$, $J/\psi$, $\psi \left(2S\right)$, and $\mathrm{{\rm Y}}\left(1S\right)$ mesons photoproduction. An analysis of the uncertainties associated with different implementations of the dipole–proton amplitude is performed. The vector meson photoproduction accompanied by electromagnetic dissociation is also analyzed. Full article

Topology optimization has been present in modern engineering for several decades, becoming an important tool for solving design problems. Today, it is difficult to imagine progress in engineering design without the search for new approaches to the generation of optimal structural topologies and the development of efficient topological optimization algorithms. The generation of topologies for structures under random loads is one of many research problems where topology optimization is present. It is important to predict the topologies of structures in the case of load uncertainty, since random load changes can significantly affect resulting topologies. This paper proposes an easy-to-implement numerical approach that allows the prediction of the resulting topologies of structures. The basic idea is to transform a random loads case into the deterministic problem of multiple loads. The concept of equivalent load scheme (ELS) is introduced. Instead of generating hundreds of loads applied at random, the selection of a few representative load cases allows the reduction of the numerical effort of the computations. The numerical implementation of proposed concepts is based on the cellular automaton mimicking colliding bodies, which has been recently introduced as an efficient structural topology generator. The examples of topology optimization under randomly applied loads, performed for both plane and spatial structures, have been selected to illustrate the proposed concepts. Confirmed by results of numerical simulations, the efficiency, versatility and ease of implementation of the proposed concept can make an original contribution to research in topological optimization under loads applied in a random manner. Full article

The Carpathian orogen represents a natural laboratory for the study of geodynamic interactions between lithospheres of different ages. The ancient Archean Cratons, such as the East European Craton, and Proterozoic platforms like the Scythian and Moesian platforms collided with the younger Tisza and Dacia mega-units, resulting in the formation of the current architecture of the Carpathian Mountains. To better understand how the lithospheric structure on Romanian territory changes from the East European Craton to younger European microplates, we use earthquake data recorded at the permanent broadband seismic stations of the Romanian National Seismic Network (RSN). Applying the multiple filter technique, we examine the dispersion of Rayleigh wave group velocities for earthquakes located within a 4000 km radius of the epicenter. Travel time tomography, conducted through fast marching surface tomography, helps us to construct group velocity maps for periods between 30 and 80 s. Our findings highlight a low-velocity body in front of the Vrancea slab, indicating asthenospheric upwelling due to slab verticalization. Full article

Ritual slaughter—understood as the killing of animals without prior stunning for religious purposes—constitutes a legally and ethically intricate domain, situated at the intersection of animal welfare, freedom of religion, public health, and consumer protection. This review offers a critical examination of the influence exerted by international and supranational jurisprudence—most notably the case law of the Court of Justice of the European Union—on the regulatory landscape governing ritual slaughter. While the right to religious freedom enjoys robust protection under European constitutional and human rights frameworks, recent judicial decisions have affirmed the legitimacy of national legislative measures mandating pre-slaughter stunning, insofar as such measures pursue objectives of animal welfare and transparency in the public interest. Particular attention is devoted to seminal rulings originating in Belgium and within the broader EU context, with a focus on the application of the principle of proportionality as a legal mechanism for balancing colliding fundamental rights. The analysis further engages with the scientific and ethical discourse surrounding animal suffering and the legal obligations tied to consumer information and labeling. Taken together, these developments reveal an emergent trajectory within EU law toward the progressive tightening of regulatory standards governing ritual slaughter, shaped by an evolving jurisprudential understanding of animal welfare imperatives. Full article

This study proposes a GPU-accelerated Position-Based Dynamics (PBD) system for realistic and interactive cloth simulation in Extended Reality (XR) environments, and comprehensively evaluates its performance and functional capabilities on standalone XR devices, such as the Meta Quest 3. To overcome the limitations of traditional CPU-based physics simulations, we designed and optimized highly parallelized algorithms utilizing Unity’s Compute Shader framework. The proposed system achieves real-time performance by implementing efficient collision detection and response handling with complex environmental meshes (RoomMesh) and dynamic hand meshes (HandMesh), as well as capsule colliders based on hand skeleton tracking (OVRSkeleton). Performance evaluations were conducted for both single-sided and double-sided cloth configurations across multiple resolutions. At a 32 × 32 resolution, both configurations maintained stable frame rates of approximately 72 FPS. At a 64 × 64 resolution, the single-sided cloth achieved around 65 FPS, while the double-sided configuration recorded approximately 40 FPS, demonstrating scalable quality adaptation depending on application requirements. Functionally, the GPU-PBD system significantly surpasses Unity’s built-in Cloth component by supporting double-sided cloth rendering, fine-grained constraint control, complex mesh-based collision handling, and real-time interaction with both hand meshes and capsule colliders. These capabilities enable immersive and physically plausible XR experiences, including natural cloth draping, grasping, and deformation behaviors during user interactions. The technical advantages of the proposed system suggest strong applicability in various XR fields, such as virtual clothing fitting, medical training simulations, educational content, and interactive art installations. Future work will focus on extending the framework to general deformable body simulation, incorporating advanced material modeling, self-collision response, and dynamic cutting simulation, thereby enhancing both realism and scalability in XR environments. Full article

The accurate identification of collision positions on containers is critical in logistics and trade for enhancing cargo safety and determining accident liability. Traditional visual inspection methods are labor-intensive, time-consuming, and costly. This study leverages data from an Inertial Measurement Unit sensor and evaluates combinations of machine learning models and feature selection methods to identify the optimal approach for collision position detection. Five machine learning models (decision tree, k-nearest neighbors, support vector machine, random forest, and extreme gradient boosting) and five feature selection methods (Pearson’s correlation coefficient, mutual information, sequential forward selection, sequential backward selection, and extra trees) were assessed using three performance metrics: accuracy, execution time, and CPU utilization. Statistical analysis with the Friedman test confirmed significant differences in model and feature selection performance. The combination of k-nearest neighbors and extra trees achieved the highest accuracy of 97.1%, demonstrating that inexpensive IMU acceleration data can provide a cost-effective, efficient, and reliable solution for collision detection. This has strong practical implications for improving accident accountability and reducing inspection costs in the logistics industry. Full article

This study investigates occupant kinematic and injury responses in zero-gravity seats under rear impacts at 16 km/h, 40 km/h, and 56 km/h and evaluates the protective performance of a conventional three-point seat belt system and a four-point seat belt system. First, a THUMS (Total Human Model for Safety)-based finite element assembly consisting of a regular seat model and a conventional three-point seat belt system was verified by comparing the kinematic responses and time-history curves of head acceleration, head rotation, and the T1 acceleration of PMHS (Postmortem Human Subject) tests. Then, a THUMS-based finite element assembly in a zero-gravity seat with a three-point seat belt system was created, and computational biomechanical analyses revealed that at low-to-medium impact speeds (16 and 40 km/h), the occupant exhibited backward sliding in the zero-gravity seat along the seatback with lower limb rotation and did not experience head and neck injury. However, a 56 km/h impact induced an excessive seatback rotation and caused the head to become out of position. The neck collided with the upper part of the headrest and caused a surge in the contact force between the neck and the headrest. The head injury and neck injury were comprehensively analyzed via the head injury metrics and neck injury metrics, including cervical spine injury metrics and cervical ligament injury metrics. Further, a four-point seat belt system was adopted and demonstrated better and more balanced restraining effects by reducing the relative displacement between the occupant’s head and chest in the x- and y-directions by 26% and 84%, respectively. Therefore, the occupant’s head remains in position and the collision between the neck and the headrest can be avoided. Maximum reductions in the head and neck injury metrics reached 70% and 57%, respectively. The current study illustrates the disadvantages of the traditional three-point seat belt system in restraining the occupant in a zero-gravity seat under rear impact and shows the four-point seat belt to be a better alternative. This study sheds light on seat belt system design and optimization towards future zero-gravity seats under rear impact. Full article

When analyzing the dynamics of wind turbines under the action of wind and ground motion, mass–point models cannot accurately predict the dynamic response of the structure. Additionally, the coupling effect between the pile foundation and the soil affects the vibration characteristics of the wind turbine. In this paper, the dynamic response of a DTU 10 MW wind turbine under the coupling effect of wind and an earthquake is numerically studied through the combined simulation of finite-element software ABAQUS 6.14-4 and OpenFAST v3.0.0. A multi-pile foundation is used as the foundation of the wind turbine structure, and the interaction between the soil and the structure is simulated by using p-y curves in the numerical model. Considering the coupling effect between the blade and the tower as well as the soil–structure coupling effect, this paper systematically investigates the vibration response of the blade–tower coupled structure under dynamic loads. The study shows that: (1) the blade vibration has a significant impact on the tower’s vibration characteristics; (2) the ground motion has varying effects on blades in different positions and will increase the out-of-plane vibration of the blades; (3) the SSI effect has a substantial impact on the out-of-plane vibration of the blade, which may cause the blade to collide with the tower, thus resulting in the failure and damage of the wind turbine structure. Full article

The ALICE (A Large Ion Collider Experiment) detector at the Large Hadron Collider (LHC), operated by the European Organization for Nuclear Research (CERN), is dedicated to heavy-ion collisions. Within ALICE, the application logs of the online computing systems are consolidated through a logging system known as Infologger, which integrates data from various sources. To identify potential anomalies, shifters in the control room manually review logs for anomalies, which require significant expertise and pose challenges due to the frequent onboarding of new personnel. To address this issue, we propose a real-time semi-supervised log anomaly detection framework designed to automatically detect anomalies in ALICE operations. The framework leverages BERTopic, a topic modeling technique, to provide real-time insights for incoming log messages for shifters. This includes an analytical dashboard that represents the anomaly status in log messages, facilitating informative monitoring for shifters. Through evaluation, including Infologger and BGL (BlueGene/L supercomputer), we analyze the effects of word embeddings, clustering algorithms, and HDBSCAN hyperparameters on model performance. The result demonstrates that the BERTopic can enhance the log anomaly detection process over traditional topic models, achieving remarkable performance metrics and attaining F1-scores of 0.957 and 0.958 for the InfoLogger and BGL datasets, respectively, even without the preprocessing technique. Full article