Previous Issue
Volume 8, March
 
 

Particles, Volume 8, Issue 2 (June 2025) – 24 articles

  • Issues are regarded as officially published after their release is announced to the table of contents alert mailing list.
  • You may sign up for e-mail alerts to receive table of contents of newly released issues.
  • PDF is the official format for papers published in both, html and pdf forms. To view the papers in pdf format, click on the "PDF Full-text" link, and use the free Adobe Reader to open them.
Order results
Result details
Select all
Export citation of selected articles as:
28 pages, 6761 KiB  
Article
Hadron Identification Prospects with Granular Calorimeters
by Andrea De Vita, Abhishek, Max Aehle, Muhammad Awais, Alessandro Breccia, Riccardo Carroccio, Long Chen, Tommaso Dorigo, Nicolas R. Gauger, Ralf Keidel, Jan Kieseler, Enrico Lupi, Federico Nardi, Xuan Tung Nguyen, Fredrik Sandin, Kylian Schmidt, Pietro Vischia and Joseph Willmore
Particles 2025, 8(2), 58; https://doi.org/10.3390/particles8020058 - 16 May 2025
Viewed by 38
Abstract
In this work we consider the problem of determining the identity of hadrons at high energies based on the topology of their energy depositions in dense matter, along with the time of the interactions. Using GEANT4 simulations of a homogeneous lead tungstate calorimeter [...] Read more.
In this work we consider the problem of determining the identity of hadrons at high energies based on the topology of their energy depositions in dense matter, along with the time of the interactions. Using GEANT4 simulations of a homogeneous lead tungstate calorimeter with high transverse and longitudinal segmentation, we investigated the discrimination of protons, positive pions, and positive kaons at 100 GeV. The analysis focuses on the impact of calorimeter granularity by progressively merging detector cells and extracting features like energy deposition patterns and timing information. Two machine learning approaches, XGBoost and fully connected deep neural networks, were employed to assess the classification performance across particle pairs. The results indicate that fine segmentation improves particle discrimination, with higher granularity yielding more detailed characterization of energy showers. Additionally, the results highlight the importance of shower radius, energy fractions, and timing variables in distinguishing particle types. The XGBoost model demonstrated computational efficiency and interpretability advantages over deep learning for tabular data structures, while achieving similar classification performance. This motivates further work required to combine high- and low-level feature analysis, e.g., using convolutional and graph-based neural networks, and extending the study to a broader range of particle energies and types. Full article
Show Figures

Figure 1

11 pages, 823 KiB  
Article
Masses and Quadrupole Deformations of Even-Z Nuclei Within a Triaxial Relativistic Hartree–Bogoliubov Model
by Qin Zhou and Zhipan Li
Particles 2025, 8(2), 57; https://doi.org/10.3390/particles8020057 - 9 May 2025
Viewed by 212
Abstract
This study investigates the masses and quadrupole deformations of even-Z nuclei within the range 8Z104 using the triaxial relativistic Hartree–Bogoliubov model (TRHB) with the PC-PK1 density functional. For odd-mass nuclei, the global minima were determined using the automatic blocking [...] Read more.
This study investigates the masses and quadrupole deformations of even-Z nuclei within the range 8Z104 using the triaxial relativistic Hartree–Bogoliubov model (TRHB) with the PC-PK1 density functional. For odd-mass nuclei, the global minima were determined using the automatic blocking method and their dynamical correlation energies (DCEs) were approximated using the average values of neighboring even–even nuclei calculated from a microscopic, five-dimensional, collective Hamiltonian (5DCH). The mean-field results underestimate the binding energies of most open-shell nuclei, with an initial root–mean–square (rms) deviation of 2.56 MeV for 1223 even-Z nuclei. Incorporating DCEs significantly reduces this deviation to 1.36 MeV. Additionally, the descriptions of two-neutron and one-neutron separation energies are improved, with rms deviations decreasing to 0.75 MeV and 0.65 MeV, respectively. Further refinement through accounting for odd–even differences in DCEs reduces the rms deviations for binding energies and one-neutron separation energies to 1.30 MeV and 0.63 MeV, respectively. Regarding the quadrupole deformations, TRHB calculations reveal spherical shapes near shell and subshell closures, well-deformed shapes at the mid-shell, and rapid shape transitions in medium- and heavy-mass regions. Oblate shapes dominate in regions (Z,N)(14,14),(34,36), and (40,60), and the neutron-deficient Pb region, with notable odd–even shape staggering attributed to the blocking effect of the odd nucleon. Triaxial shapes are favored in the mass regions (Z,N)(60,76) and (76,116). Full article
Show Figures

Figure 1

15 pages, 317 KiB  
Article
Beta Decay Properties of Waiting-Point N = 50 and 82 Isotopes
by Necla Çakmak and Najm Abdullah Saleh
Particles 2025, 8(2), 56; https://doi.org/10.3390/particles8020056 - 6 May 2025
Viewed by 164
Abstract
We performed the microscopic calculation of β-decay properties for waiting-point nuclei with neutron-closed magic shells. Allowed Gamow–Teller (GT) and first-forbidden (FF) transitions were simulated using a schematic model (SM) for waiting-point N = 50,82 isotopes in the framework of a [...] Read more.
We performed the microscopic calculation of β-decay properties for waiting-point nuclei with neutron-closed magic shells. Allowed Gamow–Teller (GT) and first-forbidden (FF) transitions were simulated using a schematic model (SM) for waiting-point N = 50,82 isotopes in the framework of a proton–neutron quasiparticle random phase approximation (pn-QRPA). The Woods–Saxon (WS) potential basis was used in our calculations. The pn-QRPA equations of allowed (GT) and (FF) transitions were utilized in both the particle–hole (ph) and particle–particle (pp) channels in the SM. We solved the secular equations of the GT and FF transitions for eigenvalues and eigenfunctions of the corresponding Hamiltonians. A spherical shape was assigned to each waiting-point nucleus in all simulations. Significantly, this study marks the first time that β-decay analysis has been applied to certain nuclei, including 82Ge50, 83As50, 84Se50, 85Br50 and 87Rb50 with N=50 isotones, and 132Sn82, 133Sb82, 134Te82, 135I82 and 137Cs82 with N=82 isotones. Since there is no prior theoretical research on these nuclei, this work is a unique addition to the field. We compared our results with the previous calculations and measured data, and our calculations agree with the experimental data and the other theoretical results. Full article
10 pages, 254 KiB  
Article
Chiral Effects in Hydrodynamics: New Trends
by Valentin Zakharov, Oleg Teryaev and Georgy Prokhorov
Particles 2025, 8(2), 55; https://doi.org/10.3390/particles8020055 - 2 May 2025
Viewed by 132
Abstract
By chiral effects, one understands the manifestations of chiral gauge anomaly and of gravitational chiral anomaly in hydrodynamics. In the last two to three years, our understanding of chiral effects has considerably changed. Here, we present a mini-review of two topics: first, a [...] Read more.
By chiral effects, one understands the manifestations of chiral gauge anomaly and of gravitational chiral anomaly in hydrodynamics. In the last two to three years, our understanding of chiral effects has considerably changed. Here, we present a mini-review of two topics: first, a shift in understanding symmetry, which underlies the chiral magnetic effect and second, the interpretation of the chiral kinematical effect uncovered recently. Full article
(This article belongs to the Special Issue Infinite and Finite Nuclear Matter (INFINUM))
11 pages, 14103 KiB  
Article
Production Optimization of Exotic Hypernuclei via Heavy-Ion Beams at GSI-FAIR
by Samuel Escrig and Christophe Rappold
Particles 2025, 8(2), 54; https://doi.org/10.3390/particles8020054 - 1 May 2025
Viewed by 178
Abstract
Building on the successful demonstration of hypernuclear spectroscopy using heavy-ion beams, the HypHI Collaboration is shifting its focus to investigating proton- and neutron-rich hypernuclei. A crucial component of this research is the implementation of a fragment separator, which facilitates the production and separation [...] Read more.
Building on the successful demonstration of hypernuclear spectroscopy using heavy-ion beams, the HypHI Collaboration is shifting its focus to investigating proton- and neutron-rich hypernuclei. A crucial component of this research is the implementation of a fragment separator, which facilitates the production and separation of rare isotope beams and is vital for accessing hypernuclei far from the stability line. High-precision spectroscopy of these exotic hypernuclei is planned to be conducted at GSI first, which will be followed by experiments at the FAIR facility utilizing the FRS and Super-FRS fragment separators. A thorough systematic investigation paired with an optimization analysis was employed to establish the most favorable experimental setup for producing high-isospin hypernuclei. Theoretical models describing heavy-ion-induced reactions and hypernuclear synthesis guided this process, which was complemented by Monte Carlo simulations to obtain experimental efficiencies for the production and transmission of the exotic secondary beams. The outlined methodology offers insights into the anticipated yields of HeΛ6, CΛ9, and a range of both proton- and neutron-rich hypernuclei. Full article
Show Figures

Figure 1

20 pages, 1548 KiB  
Article
Optimisation of Muon Tomography Scanners for Border Control Using TomOpt
by Zahraa Zaher, Samuel Alvarez, Tommaso Dorigo, Andrea Giammanco, Maxime Lagrange, Giles C. Strong, Pietro Vischia and Haitham Zaraket
Particles 2025, 8(2), 53; https://doi.org/10.3390/particles8020053 - 1 May 2025
Viewed by 515
Abstract
The TomOpt software package is designed to optimise the geometric configuration and the specifications of detectors intended for muon scattering tomography, an imaging technique exploiting cosmic-ray muons. The software employs an end-to-end differentiable pipeline that models the interactions of muons with detectors and [...] Read more.
The TomOpt software package is designed to optimise the geometric configuration and the specifications of detectors intended for muon scattering tomography, an imaging technique exploiting cosmic-ray muons. The software employs an end-to-end differentiable pipeline that models the interactions of muons with detectors and scanned volumes, infers properties of the scanned materials, and performs an optimisation cycle minimising a user-defined loss function. This article presents the implementation of a case study related to cargo scanning applications in the context of homeland security. Full article
Show Figures

Figure 1

16 pages, 1496 KiB  
Article
Neuromorphic Readout for Hadron Calorimeters
by Enrico Lupi, Abhishek, Max Aehle, Muhammad Awais, Alessandro Breccia, Riccardo Carroccio, Long Chen, Abhijit Das, Andrea De Vita, Tommaso Dorigo, Nicolas Ralph Gauger, Ralf Keidel, Jan Kieseler, Anders Mikkelsen, Federico Nardi, Xuan Tung Nguyen, Fredrik Sandin, Kylian Schmidt, Pietro Vischia and Joseph Willmore
Particles 2025, 8(2), 52; https://doi.org/10.3390/particles8020052 - 1 May 2025
Cited by 1 | Viewed by 251
Abstract
We simulate hadrons impinging on a homogeneous lead tungstate (PbWO4) calorimeter using GEANT4 software to investigate how the resulting light yield and its temporal structure, as detected by an array of light-sensitive sensors, can be processed by a neuromorphic computing [...] Read more.
We simulate hadrons impinging on a homogeneous lead tungstate (PbWO4) calorimeter using GEANT4 software to investigate how the resulting light yield and its temporal structure, as detected by an array of light-sensitive sensors, can be processed by a neuromorphic computing system. Our model encodes temporal photon distributions as spike trains and employs a fully connected spiking neural network to estimate the total deposited energy, as well as the position and spatial distribution of the light emissions within the sensitive material. The extracted primitives offer valuable topological information about the shower development in the material, achieved without requiring a segmentation of the active medium. A potential nanophotonic implementation using III-V semiconductor nanowires is discussed. It can be both fast and energy efficient. Full article
Show Figures

Figure 1

19 pages, 6110 KiB  
Article
Localized Multilayer Shielding of an Electron Beam Irradiation Station for FLASH Radiotherapy Experiments
by Kanlayaporn Kongmali, Pittaya Apiwattanakul, Phanthip Jaikeaw and Sakhorn Rimjaem
Particles 2025, 8(2), 51; https://doi.org/10.3390/particles8020051 - 1 May 2025
Viewed by 894
Abstract
FLASH radiotherapy (FLASH-RT) is a cancer treatment delivering high-dose radiation within microseconds, reducing side-effects on healthy tissues. Implementing this technology at the PBP-CMU Electron Linac Laboratory poses challenges in ensuring radiation safety within a partially underground hall with thin walls and ceiling structures. [...] Read more.
FLASH radiotherapy (FLASH-RT) is a cancer treatment delivering high-dose radiation within microseconds, reducing side-effects on healthy tissues. Implementing this technology at the PBP-CMU Electron Linac Laboratory poses challenges in ensuring radiation safety within a partially underground hall with thin walls and ceiling structures. This study develops a localized shielding design for electron beams (6–25 MeV) using the GEANT4 release 11.2.2 Monte Carlo simulation toolkit. A multilayer system of lead, iron, polyethylene, and concrete effectively attenuates X-rays, gamma-rays, and neutrons, achieving dose levels below 1 mSv/year for public areas and within 20 mSv/year for controlled areas, meeting international standards. The B-factor analysis highlights efficient low-energy gamma attenuation and thicker shielding requirements for high-energy rays. The design minimizes radiation leakage, ensuring safe operation for FLASH-RT while safeguarding personnel and the environment. Future work includes constructing and validating the system, with methodologies applicable to other electron beam facilities. Full article
(This article belongs to the Special Issue Generation and Application of High-Power Radiation Sources 2025)
Show Figures

Figure 1

10 pages, 4218 KiB  
Article
Front-End Prototype ASIC with Low-Gain Avalanche Detector Sensors for the ATLAS High Granularity Timing Detector
by Salah El Dine Hammoud
Particles 2025, 8(2), 50; https://doi.org/10.3390/particles8020050 - 1 May 2025
Viewed by 152
Abstract
Timing measurements are critical for the detectors at the future HL-LHC, to resolve reconstruction ambiguity when the number of simultaneous interactions reaches up to 200 per bunch crossing. The ATLAS collaboration therefore builds a new High-Granularity Timing detector for the forward region. A [...] Read more.
Timing measurements are critical for the detectors at the future HL-LHC, to resolve reconstruction ambiguity when the number of simultaneous interactions reaches up to 200 per bunch crossing. The ATLAS collaboration therefore builds a new High-Granularity Timing detector for the forward region. A customized ASIC, called ALTIROC, has been developed, to read out fast signals from low-gain avalanche detectors (LGADs), which has 50 ps time-resolution for signals from minimum-ionizing particles. To meet these requirements, a custom-designed pre-amplifier, a discriminator, and TDC circuits with minimal jitter have been implemented in a series of prototype ASICs. The latest version, ALTIROC3, is designed to contain full functionality. Hybrid assemblies with ALTIROC3 ASICs and LGAD sensors have been characterized with charged-particle beams at CERN-SPS and with laser-light injection. The time-jitter contributions of the sensor, pre-amplifier, discriminator, TDC, and digital readout are evaluated. Full article
Show Figures

Figure 1

9 pages, 2062 KiB  
Article
Versal Adaptive Compute Acceleration Platform Processing for ATLAS-TileCal Signal Reconstruction
by Francisco Hervás Álvarez, Alberto Valero Biot, Luca Fiorini, Héctor Gutiérrez Arance, Fernando Carrió, Sonakshi Ahuja and Francesco Curcio
Particles 2025, 8(2), 49; https://doi.org/10.3390/particles8020049 - 1 May 2025
Viewed by 168
Abstract
Particle detectors at accelerators generate large amounts of data, requiring analysis to derive insights. Collisions lead to signal pile-up, where multiple particles produce signals in the same detector sensors, complicating individual signal identification. This contribution describes the implementation of a deep-learning algorithm on [...] Read more.
Particle detectors at accelerators generate large amounts of data, requiring analysis to derive insights. Collisions lead to signal pile-up, where multiple particles produce signals in the same detector sensors, complicating individual signal identification. This contribution describes the implementation of a deep-learning algorithm on a Versal Adaptive Compute Acceleration Platform (ACAP) device for improved processing via parallelization and concurrency. Connected to a host computer via Peripheral Component Interconnect express (PCIe), this system aims for enhanced speed and energy efficiency over Central Processing Units (CPUs) and Graphics Processing Units (GPUs). In the contribution, we will describe in detail the data processing and the hardware, firmware and software components of the system. The contribution presents the implementation of the deep-learning algorithm on a Versal ACAP device, as well as the system for transferring data in an efficient way. Full article
Show Figures

Figure 1

11 pages, 837 KiB  
Article
Development and Explainability of Models for Machine-Learning-Based Reconstruction of Signals in Particle Detectors
by Kalina Dimitrova, Venelin Kozhuharov and Peicho Petkov
Particles 2025, 8(2), 48; https://doi.org/10.3390/particles8020048 - 23 Apr 2025
Viewed by 224
Abstract
Machine learning methods are being introduced at all stages of data reconstruction and analysis in various high-energy physics experiments. We present the development and application of convolutional neural networks with modified autoencoder architecture for the reconstruction of the pulse arrival time and amplitude [...] Read more.
Machine learning methods are being introduced at all stages of data reconstruction and analysis in various high-energy physics experiments. We present the development and application of convolutional neural networks with modified autoencoder architecture for the reconstruction of the pulse arrival time and amplitude in individual scintillating crystals in electromagnetic calorimeters and other detectors. The network performance is discussed as well as the application of xAI methods for further investigation of the algorithm and improvement of the output accuracy. Full article
Show Figures

Figure 1

16 pages, 820 KiB  
Article
End-to-End Detector Optimization with Diffusion Models: A Case Study in Sampling Calorimeters
by Kylian Schmidt, Krishna Nikhil Kota, Jan Kieseler, Andrea De Vita, Markus Klute, Abhishek, Max Aehle, Muhammad Awais, Alessandro Breccia, Riccardo Carroccio, Long Chen, Tommaso Dorigo, Nicolas R. Gauger, Enrico Lupi, Federico Nardi, Xuan Tung Nguyen, Fredrik Sandin, Joseph Willmore and Pietro Vischia
Particles 2025, 8(2), 47; https://doi.org/10.3390/particles8020047 - 23 Apr 2025
Viewed by 355
Abstract
Recent advances in machine learning have opened new avenues for optimizing detector designs in high-energy physics, where the complex interplay of geometry, materials, and physics processes has traditionally posed a significant challenge. In this work, we introduce the end-to-end. AI Detector Optimization framework [...] Read more.
Recent advances in machine learning have opened new avenues for optimizing detector designs in high-energy physics, where the complex interplay of geometry, materials, and physics processes has traditionally posed a significant challenge. In this work, we introduce the end-to-end. AI Detector Optimization framework (AIDO), which leverages a diffusion model as a surrogate for the full simulation and reconstruction chain, enabling gradient-based design exploration in both continuous and discrete parameter spaces. Although this framework is applicable to a broad range of detectors, we illustrate its power using the specific example of a sampling calorimeter, focusing on charged pions and photons as representative incident particles. Our results demonstrate that the diffusion model effectively captures critical performance metrics for calorimeter design, guiding the automatic search for a layer arrangement and material composition that align with known calorimeter principles. The success of this proof-of-concept study provides a foundation for the future applications of end-to-end optimization to more complex detector systems, offering a promising path toward systematically exploring the vast design space in next-generation experiments. Full article
Show Figures

Figure 1

26 pages, 2940 KiB  
Review
Cosmic Ray Muon Navigation for Subsurface Environments: Technologies and Challenges
by Dongqing Zhao, Pengfei Li and Linyang Li
Particles 2025, 8(2), 46; https://doi.org/10.3390/particles8020046 - 22 Apr 2025
Viewed by 317
Abstract
The global navigation satellite system (GNSS), using electromagnetic signals, enables continuous positioning throughout the entire surface of the Earth. However, underwater and underground environments significantly restrict the propagation of electromagnetic waves. The sole approach to aid positioning is the utilization of sound signals. [...] Read more.
The global navigation satellite system (GNSS), using electromagnetic signals, enables continuous positioning throughout the entire surface of the Earth. However, underwater and underground environments significantly restrict the propagation of electromagnetic waves. The sole approach to aid positioning is the utilization of sound signals. Signal blockage in underground and indoor environments demands the accurate location of anchor points for local positioning, which requires previous deployment. Unlike radio waves, the cosmic ray muons are highly reliable natural signal sources for positioning, remaining immune to spoofing and interference. Starting from the standpoint of navigation and positioning, this paper briefly introduces the physical properties of cosmic ray muons and outlines the measurements and positioning principles of muon navigation, including trilateral localization based on the time of flight (TOF) and angular localization based on the angle of arrival (AOA). It subsequently presents the pertinent studies conducted and analyzes the findings. Finally, the challenges of muon navigation are explored from three perspectives: positioning signals, positioning models, and application scenarios. This will offer some new ideas for the domain of localization for further research on muon positioning. Full article
Show Figures

Figure 1

10 pages, 5511 KiB  
Review
Multimessenger Studies with the Pierre Auger Observatory
by Jon Paul Lundquist and the Pierre Auger Collaboration
Particles 2025, 8(2), 45; https://doi.org/10.3390/particles8020045 - 22 Apr 2025
Viewed by 177
Abstract
The Pierre Auger Observatory, the world’s largest ultra-high-energy (UHE) cosmic ray (CR) detector, plays a crucial role in multi-messenger astroparticle physics with its high sensitivity to UHE photons and neutrinos. Recent Auger Observatory studies have set stringent limits on the diffuse and point-like [...] Read more.
The Pierre Auger Observatory, the world’s largest ultra-high-energy (UHE) cosmic ray (CR) detector, plays a crucial role in multi-messenger astroparticle physics with its high sensitivity to UHE photons and neutrinos. Recent Auger Observatory studies have set stringent limits on the diffuse and point-like fluxes of these particles, enhancing constraints on dark-matter models and UHECR sources. Although no temporal coincidences of neutrinos or photons with LIGO/Virgo gravitational wave events have been observed, competitive limits on the energy radiated in these particles have been established, particularly from the GW170817 binary neutron star merger. Additionally, correlations between the arrival directions of UHECRs and high-energy neutrinos have been explored using data from the IceCube Neutrino Observatory, ANTARES, and the Auger Observatory, providing additional neutrino flux constraints. Efforts to correlate UHE neutron fluxes with gamma-ray sources within our galaxy continue, although no significant excesses have been found. These collaborative and multi-faceted efforts underscore the pivotal role of the Auger Observatory in advancing multi-messenger astrophysics and probing the most extreme environments of the Universe. Full article
Show Figures

Figure 1

9 pages, 340 KiB  
Article
A Systematic Approach to Studying Quark Energy Loss in Nuclei Using Positive Pions
by Nicolás Zambra-Gómez, William K. Brooks and Nicolás Viaux
Particles 2025, 8(2), 44; https://doi.org/10.3390/particles8020044 - 15 Apr 2025
Viewed by 196
Abstract
Our objective is to test the published models of partonic energy loss, particularly those describing the energy loss mechanisms of quarks traversing nuclear matter, within the framework of semi-inclusive deep inelastic scattering. Our methodological approach focuses on quantifying the quark energy loss in [...] Read more.
Our objective is to test the published models of partonic energy loss, particularly those describing the energy loss mechanisms of quarks traversing nuclear matter, within the framework of semi-inclusive deep inelastic scattering. Our methodological approach focuses on quantifying the quark energy loss in cold matter by analyzing the positive pions (π+) produced in various nuclear targets, including deuterium, carbon, iron and lead, while our first approach only includes deuterium and carbon. Before normalizing the pions’ energy distribution to unity to perform a shape analysis, acceptance corrections were performed to account for the detector’s efficiency and ensure accurate comparisons of the spectra. By normalizing the energy spectra of π+ produced from these distinct targets and based on the Baier–Dokshitzer–Mueller–Peigné–Schiff theory, which posits that quark energy loss depends only on nuclear size, it is assumed that the energy distributions of the targets will exhibit similar behavior. For this normalization, an energy shift between these distributions, corresponding to the quark energy loss, is identified. To ensure accuracy, statistical techniques such as the Kolmogorov–Smirnov test are used. The data used to test and explore the analysis technique and method were from the CLAS6 EG2 dataset collected using Jefferson Lab’s CLAS detector. Full article
Show Figures

Figure 1

20 pages, 2061 KiB  
Article
Scattering-Based Machine Learning Algorithms for Momentum Estimation in Muon Tomography
by Florian Bury and Maxime Lagrange
Particles 2025, 8(2), 43; https://doi.org/10.3390/particles8020043 - 14 Apr 2025
Viewed by 456
Abstract
Muon tomography leverages the small, continuous flux of cosmic rays produced in the upper atmosphere to measure the density of unknown volumes. The multiple Coulomb scattering that muons undergo when passing through the material can either be leveraged or represent a measurement nuisance. [...] Read more.
Muon tomography leverages the small, continuous flux of cosmic rays produced in the upper atmosphere to measure the density of unknown volumes. The multiple Coulomb scattering that muons undergo when passing through the material can either be leveraged or represent a measurement nuisance. In either case, the scattering dependence on muon momentum is a significant source of imprecision. This can be alleviated by including dedicated momentum measurement devices in the experiment, which have a potential cost and can interfere with measurement. An alternative consists of leveraging information on scattering withstood through a known medium. We present a comprehensive study of diverse machine-learning algorithms for this regression task, from classical feature engineering with a fully connected network to more advanced architectures such as recurrent and graph neural networks and transformers. Several real-life requirements are considered, such as the inclusion of hit reconstruction efficiency and resolution and the need for a momentum resolution prediction that can improve reconstruction methods. Full article
Show Figures

Figure 1

10 pages, 392 KiB  
Article
Calculation of α Decay Half-Lives for Tl, Bi, and At Isotopes
by Myeong-Hwan Mun, Kyoungsu Heo and Myung-Ki Cheoun
Particles 2025, 8(2), 42; https://doi.org/10.3390/particles8020042 - 11 Apr 2025
Viewed by 216
Abstract
We investigated the reaction Q-value (Qα) for the α decay of Tl, Bi, and At isotopes using the deformed relativistic Hartree–Bogoliubov theory in continuum (DRHBc) with the covariant density functional PC-PK1. The α decay half-lives of Tl, Bi, and At [...] Read more.
We investigated the reaction Q-value (Qα) for the α decay of Tl, Bi, and At isotopes using the deformed relativistic Hartree–Bogoliubov theory in continuum (DRHBc) with the covariant density functional PC-PK1. The α decay half-lives of Tl, Bi, and At isotopes are evaluated using various empirical formulas, based on both experimental Qα and those obtained from DRHBc calculations. The calculated Qα and α decay half-lives are compared with experimental data. On the basis of these results, we also predicted the α decay half-lives of isotopes for which experimental data are unavailable. Full article
Show Figures

Figure 1

6 pages, 1393 KiB  
Article
Results from Cryo-PoF Project: Power over Fiber at Cryogenic Temperature for Fundamental and Applied Physics
by Andrea Falcone, Alessandro Andreani, Claudia Brizzolari, Esteban Javier Cristaldo Morales, Maritza Juliette Delgado Gonzales, Claudio Gotti, Massimo Lazzaroni, Luca Meazza, Gianluigi Pessina, Francesco Terranova, Marta Torti and Valeria Trabattoni
Particles 2025, 8(2), 41; https://doi.org/10.3390/particles8020041 - 8 Apr 2025
Viewed by 224
Abstract
The Cryo-PoF project is an R&D project funded by the Italian Insitute for Nuclear Research (INFN) in Milano-Bicocca (Italy). The technology at the basis of the project is Power over Fiber (PoF). By sending laser light through an optical fiber, this technology delivers [...] Read more.
The Cryo-PoF project is an R&D project funded by the Italian Insitute for Nuclear Research (INFN) in Milano-Bicocca (Italy). The technology at the basis of the project is Power over Fiber (PoF). By sending laser light through an optical fiber, this technology delivers electrical power to a photovoltaic power converter, in order to power sensors or electrical devices. Among the several advantages this solution can provide, we can underline the spark-free operation when electric fields are present, the removal of noise induced by power lines, the absence of interference with electromagnetic fields, and robustness in hostile environments. R&D for the application of PoF in cryogenic environments started at Fermilab in 2020; for the DUNE Vertical Drift detector, it was needed to operate the Photon Detector System on a high-voltage cathode surface. Cryo-PoF, starting from this project, developed a single-laser input line system to power, at cryogenic temperatures, both an electronic amplifier and Photon Detection devices, tuning their bias by means of the input laser power, without adding ancillary fibers. The results obtained in Milano-Bicocca will be discussed, presenting the tests performed using power photosensors at liquid nitrogen temperature. Full article
Show Figures

Figure 1

25 pages, 1460 KiB  
Article
Unsupervised Particle Tracking with Neuromorphic Computing
by Emanuele Coradin, Fabio Cufino, Muhammad Awais, Tommaso Dorigo, Enrico Lupi, Eleonora Porcu, Jinu Raj, Fredrik Sandin and Mia Tosi
Particles 2025, 8(2), 40; https://doi.org/10.3390/particles8020040 - 7 Apr 2025
Viewed by 403
Abstract
We study the application of a neural network architecture for identifying charged particle trajectories via unsupervised learning of delays and synaptic weights using a spike-time-dependent plasticity rule. In the considered model, the neurons receive time-encoded information on the position of particle hits in [...] Read more.
We study the application of a neural network architecture for identifying charged particle trajectories via unsupervised learning of delays and synaptic weights using a spike-time-dependent plasticity rule. In the considered model, the neurons receive time-encoded information on the position of particle hits in a tracking detector for a particle collider, modeled according to the geometry of the Compact Muon Solenoid Phase-2 detector. We show how a spiking neural network is capable of successfully identifying in a completely unsupervised way the signal left by charged particles in the presence of conspicuous noise from accidental or combinatorial hits, opening the way to applications of neuromorphic computing to particle tracking. The presented results motivate further studies investigating neuromorphic computing as a potential solution for real-time, low-power particle tracking in future high-energy physics experiments. Full article
Show Figures

Figure 1

9 pages, 3124 KiB  
Article
Information Field Theory for Two Applications in Astroparticle Physics
by Martin Erdmann, Frederik Krieger, Alex Reuzki, Josina Schulte, Michael Smolka and Maximilian Straub
Particles 2025, 8(2), 39; https://doi.org/10.3390/particles8020039 - 7 Apr 2025
Viewed by 286
Abstract
Information field theory (IFT) provides a powerful framework for reconstructing continuous fields from noisy and sparse data. Based on Bayesian statistics, IFT allows for the approximation of posterior distributions over field-like parameter spaces in high-dimensional problems. In this contribution, we discuss two applications [...] Read more.
Information field theory (IFT) provides a powerful framework for reconstructing continuous fields from noisy and sparse data. Based on Bayesian statistics, IFT allows for the approximation of posterior distributions over field-like parameter spaces in high-dimensional problems. In this contribution, we discuss two applications of IFT in the context of astroparticle physics. First, we present its intended use for the calibration of the newly installed radio detector upgrade of the Pierre Auger Observatory. Second, we demonstrate its application to infer the initial directions of ultra-high-energy cosmic rays before their deflection in the Galactic magnetic field using a simplified model. Full article
Show Figures

Figure 1

14 pages, 962 KiB  
Article
Probing QGP-like Dynamics via Multi-Strange Hadron Production in High-Multiplicity pp Collisions
by Haifa I. Alrebdi, Muhammad Ajaz, Muhammad Waqas, Maryam Waqar and Taoufik Saidani
Particles 2025, 8(2), 38; https://doi.org/10.3390/particles8020038 - 4 Apr 2025
Viewed by 273
Abstract
This study employs Monte Carlo (MC) models and thermal-statistical analysis to investigate the production mechanisms of strange (KS0, Λ) and multi-strange (Ξ, Ω) hadrons in high-multiplicity proton–proton collisions. Through systematic comparisons with experimental data, we [...] Read more.
This study employs Monte Carlo (MC) models and thermal-statistical analysis to investigate the production mechanisms of strange (KS0, Λ) and multi-strange (Ξ, Ω) hadrons in high-multiplicity proton–proton collisions. Through systematic comparisons with experimental data, we evaluate the predictive power of EPOS, PYTHIA8, QGSJETII04, and Sibyll2.3d. EPOS, with its hydrodynamic evolution, successfully reproduces low-pTKS0 and Λ yields in high-multiplicity classes (MC1–MC3), mirroring quark-gluon plasma (QGP) thermalization effects. PYTHIA8’s rope hadronization partially mitigates mid-pT multi-strange baryon suppression but underestimates Ξ and Ω yields due to the absence of explicit medium dynamics. QGSJETII04, tailored for cosmic-ray showers, overpredicts soft KS0 yields from excessive soft Pomeron contributions and lacks multi-strange hadron predictions due to enforced decays. Sibyll2.3d’s forward-phase bias limits its accuracy at midrapidity. No model fully captures Ξ and Ω production, though EPOS remains the closest. Complementary Tsallis distribution analysis reveals a distinct mass-dependent hierarchy in the extracted effective temperature (Teff) and non-extensivity parameter (q). As multiplicity decreases, Teff rises while q declines—a trend amplified for heavier particles. This suggests faster equilibration of heavier particles compared to lighter species. The interplay of these findings underscores the necessity of incorporating QGP-like medium effects and refined strangeness enhancement mechanisms in MC models to describe small-system collectivity. Full article
Show Figures

Figure 1

8 pages, 1295 KiB  
Article
Bubble Structure in Isotopes of Lu to Hg
by Changhoon Song, Yongbeom Choi, Youngman Kim and Chang-Hwan Lee
Particles 2025, 8(2), 37; https://doi.org/10.3390/particles8020037 - 2 Apr 2025
Viewed by 274
Abstract
Bubble nuclei, characterized by a depletion in nucleon density at the nuclear center, are investigated within the atomic number range 71Z80 using the Deformed Relativistic Hartree–Bogoliubov theory in continuum. This study extends previous investigations, which were limited to even–even [...] Read more.
Bubble nuclei, characterized by a depletion in nucleon density at the nuclear center, are investigated within the atomic number range 71Z80 using the Deformed Relativistic Hartree–Bogoliubov theory in continuum. This study extends previous investigations, which were limited to even–even isotopes, by incorporating even–odd, odd–even, and odd–odd nuclei within this range. The extension is achieved by introducing the blocking effect into the point-coupling approach to ensure self-consistency. Following previous studies, we define a nucleus as a bubble candidate if the bubble parameter exceeds Bp=20%, and identify five bubble nuclei in both even-Z and odd-Z nuclei groups, based on the highest Bp values. The formation of bubble structures is confirmed through an analysis of proton single-particle energy levels of the most centrally depleted nuclei across four categories: even–odd, even–even, odd–even, and odd–odd. Full article
Show Figures

Figure 1

13 pages, 6249 KiB  
Article
The High-Granularity Timing Detector for ATLAS at HL-LHC
by Joaquim Pinol
Particles 2025, 8(2), 36; https://doi.org/10.3390/particles8020036 - 1 Apr 2025
Viewed by 201
Abstract
The increased particle flux expected at the HL-LHC poses a serious challenge for the ATLAS detector performance, especially in the forward region. The High-Granularity Timing Detector (HGTD), featuring novel Low-Gain Avalanche Detector silicon technology, will provide pile-up mitigation and luminosity measurement capabilities, and [...] Read more.
The increased particle flux expected at the HL-LHC poses a serious challenge for the ATLAS detector performance, especially in the forward region. The High-Granularity Timing Detector (HGTD), featuring novel Low-Gain Avalanche Detector silicon technology, will provide pile-up mitigation and luminosity measurement capabilities, and augment the new all-silicon Inner Tracker in the pseudo-rapidity range from 2.4 to 4.0. Two double-sided layers will provide a timing resolution better than 50 ps/track for MIPs throughout the HL-LHC running period, and provide a new timing-based handle to assign particles to the correct vertex. The LGAD technology provides suitable gain to reach the required signal-to-noise ratio, and a granularity of 1.3 × 1.3 mm2 (with 3.6 M channels in total). This paper presents the current status of the HGTD project with emphasis on the sensor development and module results. Full article
Show Figures

Figure 1

11 pages, 323 KiB  
Article
HYDrodynamics with JETs (HYDJET++): Latest Developments and Results
by Garnik Ambaryan, Larissa Bravina, Alexey Chernyshov, Gyulnara Eyyubova, Vladimir Korotkikh, Igor Lokhtin, Sergei Petrushanko, Alexandr Snigirev and Evgeny Zabrodin
Particles 2025, 8(2), 35; https://doi.org/10.3390/particles8020035 - 1 Apr 2025
Viewed by 202
Abstract
Analysis of the (i) charge balance function and (ii) fluctuations of the net electric charge of hadrons in Pb+Pb collisions at center-of-mass energy 2.76 TeV per nucleon pair was performed within a two-component hydjet++ model. It is shown that [...] Read more.
Analysis of the (i) charge balance function and (ii) fluctuations of the net electric charge of hadrons in Pb+Pb collisions at center-of-mass energy 2.76 TeV per nucleon pair was performed within a two-component hydjet++ model. It is shown that neither the widths of the balance function nor the strongly intensive quantities, D and Σ, used to describe the net-charge fluctuations, can be reproduced within the model based on a grand canonical ensemble approach for generating multiparticle production. To solve this problem, it is necessary to take into account exact charge conservation in an event-by-event basis. The corresponding procedure was developed and implemented in the modified hydjet++ model. It provides a fair description of the experimental data. Full article
Show Figures

Figure 1

Previous Issue
Back to TopTop