Particles

12 pages, 2330 KB

Open AccessArticle

Enhanced Energy Transfer in Resonating Gold Doped Matter Irradiated by Infrared Laser

by Konstantin Zsukovszki and Istvan Papp

Particles 2025, 8(4), 104; https://doi.org/10.3390/particles8040104 - 18 Dec 2025

Laser-driven ion acceleration in dense, hydrogen-rich media can be significantly enhanced by embedding metallic nanoantennas that support localized surface plasmon (LSP) resonances. Using large-scale particle-in-cell (PIC) simulations with the EPOCH code, we investigate how nanoantenna geometry and laser pulse parameters influence proton acceleration [...] Read more.

Laser-driven ion acceleration in dense, hydrogen-rich media can be significantly enhanced by embedding metallic nanoantennas that support localized surface plasmon (LSP) resonances. Using large-scale particle-in-cell (PIC) simulations with the EPOCH code, we investigate how nanoantenna geometry and laser pulse parameters influence proton acceleration in gold-doped polymer targets. The study covers dipole, crossed, and advanced 3D-cross antenna configurations under laser intensities of 10¹⁷–10¹⁹ W/cm² and pulse durations from 2.5 to 500 fs, corresponding to experimental conditions at the ELI laser facility. Results show that the dipole antennas exhibit resonance-limited proton energies of ~0.12 MeV, with optimal acceleration at the intensities 4 × 10¹⁷–1 × 10¹⁸ W/cm² and pulse durations around 100–150 fs. This energy is higher by roughly three orders of magnitude than the proton energy for the same field and same polymer without dopes: ~1–2 × 10⁻⁴ MeV. Crossed antennas achieve higher energies (~0.2 MeV) due to dual-mode plasmonic coupling that sustains local fields longer. Advanced 3D and Yagi-like geometries further enhance field localization, yielding proton energies up to 0.4 MeV and larger high-energy proton populations. For dipole antennas, experimental data from ELI exists and our results agree with it. We find that moderate pulses preserve plasmonic resonance for longer and improve energy transfer efficiency, while overly intense pulses disrupt the resonance early. These findings reveal that plasmonic field enhancement and its lifetime govern energy transfer efficiency in laser–matter interaction. Crossed and 3D geometries with optimized spacing enable multimode resonance and sequential proton acceleration, overcoming the saturation limitations of simple dipoles. The results establish clear design principles for tailoring nanoantenna geometry and pulse characteristics to optimize compact, high-energy proton sources for inertial confinement fusion and high-energy-density applications. Full article

(This article belongs to the Special Issue Selected Papers from the 14th International Conference on New Frontiers in Physics (ICNFP 2025))

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12 pages, 610 KB

Open AccessArticle

Insights into the Temperature Parameters from K*⁰ Spectrum in Nuclear Particle Collisions at the Relativistic High-Energy Collider Beam Energies

by Pei-Pin Yang and Abd Haj Ismail

Particles 2025, 8(4), 103; https://doi.org/10.3390/particles8040103 - 15 Dec 2025

Viewed by 94

Abstract

The blast-wave model with Boltzmann–Gibbs statistics is used to examine the transverse momentum spectra of

{K *}^{0}

mesons generated at the Relativistic High-Energy Collider (RHIC) Beam Energies with mid-rapidity (

| y | < 1

) in symmetric [...] Read more.

The blast-wave model with Boltzmann–Gibbs statistics is used to examine the transverse momentum spectra of

{K *}^{0}

mesons generated at the Relativistic High-Energy Collider (RHIC) Beam Energies with mid-rapidity (

| y | < 1

) in symmetric

A u - A u

collisions. There is a clear correlation between the extracted kinetic freeze-out temperature (

T_{0}

) and transverse flow velocity (

β_{T}

) in various collision centralities and center-of-mass energies (

\sqrt{s_{N N}}

). Since a larger initial energy density delays freeze-out and a shorter system lifetime limits cooling,

T_{0}

is directly proportional to both

\sqrt{s_{N N}}

and peripheral collisions. On the other hand,

β_{T}

drops in peripheral symmetric collisions due to weaker collective expansion, while it rises with

\sqrt{s_{N N}}

because of larger pressure gradients. The concurrence between the thermal and collective energy components in the expanding fireball is reflected in the obvious anti-correlation between

T_{0}

and

β_{T}

. These findings support hydrodynamic predictions and offer important new information about QGP’s freeze-out behavior. Full article

(This article belongs to the Special Issue Advances in QCD: Bridging Heavy-Ion Collisions and Electron Scattering at the Electron-Ion Collider)

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8 pages, 472 KB

Open AccessPerspective

Onboard Machine Learning for High-Energy Observatories for Spacecraft Autonomy and Ground Segment Operations

by Andrea Bulgarelli, Luca Castaldini, Nicolò Parmiggiani, Ambra Di Piano, Riccardo Falco, Alessio Aboudan, Lorenzo Amati, Andrea Argan, Paolo Calabretto, Mauro Dadina, Adriano De Rosa, Valentina Fioretti, Claudio Labanti, Giulia Mattioli, Gabriele Panebianco, Carlotta Pittori, Alessandro Rizzo, Smiriti Srivastava and Enrico Virgilli

Particles 2025, 8(4), 102; https://doi.org/10.3390/particles8040102 - 12 Dec 2025

Viewed by 243

Abstract

Next-generation space observatories for high-energy gamma-ray astrophysics will increase scientific return using onboard machine learning (ML). This is now possible thanks to today’s low-power, radiation-tolerant processors and artificial intelligence accelerators. This paper provides an overview of current and future ML applications in gamma-ray [...] Read more.

Next-generation space observatories for high-energy gamma-ray astrophysics will increase scientific return using onboard machine learning (ML). This is now possible thanks to today’s low-power, radiation-tolerant processors and artificial intelligence accelerators. This paper provides an overview of current and future ML applications in gamma-ray space missions focused on high-energy transient phenomena. We discuss onboard ML use cases that will be implemented in the future, including real-time event detection and classification (e.g., gamma-ray bursts), and autonomous decision-making, such as rapid repointing to transient events or optimising instrument configuration based on the scientific target or environmental conditions. Full article

(This article belongs to the Special Issue Advances in Space AstroParticle Physics: Frontier Technologies for Particle Measurements in Space, 2025 Edition)

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21 pages, 668 KB

Open AccessArticle

The EPSI R&D: Development of an Innovative Electron–Positron Discrimination Technique for Space Applications

by Oscar Adriani, Lucia Baldesi, Eugenio Berti, Pietro Betti, Massimo Bongi, Alberto Camaiani, Massimo Chiari, Raffaello D’Alessandro, Giacomo De Giorgi, Noemi Finetti, Leonardo Forcieri, Elena Gensini, Andrea Paccagnella, Lorenzo Pacini, Paolo Papini, Oleksandr Starodubtsev, Anna Vinattieri and Chiara Volpato

Particles 2025, 8(4), 101; https://doi.org/10.3390/particles8040101 - 12 Dec 2025

Viewed by 132

Abstract

The study of the antimatter component in cosmic rays is essential for the understanding of their acceleration and propagation mechanisms, and is one of the most powerful tools for the indirect search of dark matter. Current methods rely on magnetic spectrometers for charge-sign [...] Read more.

The study of the antimatter component in cosmic rays is essential for the understanding of their acceleration and propagation mechanisms, and is one of the most powerful tools for the indirect search of dark matter. Current methods rely on magnetic spectrometers for charge-sign discrimination, but these are not suitable for extending measurements to the TeV region within a short timeframe of a few decades. Since most of present and upcoming high-energy space experiments use large calorimeters, it is crucial to develop an alternative charge-sign discrimination technique that can be integrated with them. The Electron/Positron Space Instrument (EPSI) project, a two-year R&D initiative launched in 2023 with EU recovery funds, aims to address this challenge. The basic idea is to exploit the synchrotron radiation emitted by charged particles moving through Earth’s magnetic field. The simultaneous detection of an electron/positron with an electromagnetic calorimeter and synchrotron photons with an X-ray detector is enough to discriminate between the two particles at the event level. The main challenge is to develop an X-ray detector with a very large active area, high X-ray detection efficiency, and a low-energy detection threshold, compliant with space applications. In this paper, we give an overview of the EPSI project, with a focus on the general idea of the detection principle, the concept of the space instrument, and the design of the X-ray detector. Full article

(This article belongs to the Special Issue Advances in Space AstroParticle Physics: Frontier Technologies for Particle Measurements in Space, 2025 Edition)

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27 pages, 640 KB

Open AccessArticle

Neutrino-Pair Bremsstrahlung Due to Electromagnetic Collisions in Neutron Star Cores Revisited

by Peter S. Shternin

Particles 2025, 8(4), 100; https://doi.org/10.3390/particles8040100 - 11 Dec 2025

Viewed by 185

Abstract

We reconsider the problem of neutrino-pair bremsstrahlung emission originating from the electromagnetic collisions of charged particles in nucleonic (

n p e μ

) neutron star cores. Two limiting cases are considered: (i) protons in the normal state and (ii) protons in the [...] Read more.

We reconsider the problem of neutrino-pair bremsstrahlung emission originating from the electromagnetic collisions of charged particles in nucleonic (

n p e μ

) neutron star cores. Two limiting cases are considered: (i) protons in the normal state and (ii) protons in the superconducting state. In both cases, the dominant contribution to the bremsstrahlung emissivity

Q_{Br}^{em}

comes from the transverse part of in-medium electromagnetic interactions. For non-superconducting matter, we obtain an unusual

Q_{Br}^{em} \propto T^{23 / 3}

temperature dependence due to the dynamical character of plasma screening in the transverse channel, but these are considerably smaller values of

Q_{Br}^{em}

than in previous studies, rendering the considered process unimportant in practice. In contrast, for superconducting and superfluid matter, the neutrino emission processes involving nucleons are suppressed and

Q_{Br}^{em}

due to lepton collisions provides the residual contribution to the neutrino emissivity of neutron star core matter. In the superconducting case, the plasma screening becomes static and the standard

Q_{Br}^{em} \propto T^{8}

temperature scaling is restored. Simple analytical expressions for

Q_{Br}^{em}

in both limiting cases are provided. Full article

(This article belongs to the Special Issue Infinite and Finite Nuclear Matter (INFINUM))

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13 pages, 1899 KB

Open AccessArticle

Pattern Recognition with Artificial Intelligence in Space Experiments

by Federica Cuna, Maria Bossa, Fabio Gargano and Mario Nicola Mazziotta

Particles 2025, 8(4), 99; https://doi.org/10.3390/particles8040099 - 10 Dec 2025

Viewed by 169

Abstract

The application of advanced Artificial Intelligence (AI) techniques in astroparticle experiments represents a major advancement in both data analysis and experimental design. As space missions become increasingly complex, integrating AI tools is essential for optimizing system performance and maximizing scientific return. This study [...] Read more.

The application of advanced Artificial Intelligence (AI) techniques in astroparticle experiments represents a major advancement in both data analysis and experimental design. As space missions become increasingly complex, integrating AI tools is essential for optimizing system performance and maximizing scientific return. This study explores the use of Graph Neural Networks (GNNs) within the tracking systems of space-based experiments. A key challenge in track reconstruction is the high level of noise, primarily due to backscattering tracks, which can obscure the identification of primary particle trajectories. We propose a novel GNN-based approach for node-level classification tasks, specifically designed to distinguish primary tracks from backscattered ones within the tracker. In this framework, AI is employed as a powerful tool for pattern recognition, enabling the system to identify meaningful structures within complex tracking data and to discriminate signal from backscattering with higher precision. By addressing these challenges, our work aims to enhance the accuracy and reliability of data interpretation in astroparticle physics through the advanced deep learning techniques. Full article

(This article belongs to the Special Issue Advances in Space AstroParticle Physics: Frontier Technologies for Particle Measurements in Space, 2025 Edition)

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18 pages, 2016 KB

Open AccessArticle

Magnetic Field Amplification and Reconstruction in Rotating Astrophysical Plasmas: Verifying the Roles of α and β in Dynamo Action

by Kiwan Park

Particles 2025, 8(4), 98; https://doi.org/10.3390/particles8040098 - 4 Dec 2025

Viewed by 110

Abstract

We investigate the

α

and

β

effects in a rotating spherical plasma system relevant to astrophysical contexts. In particular, we focus on how kinetic and magnetic (current) helicities influence the magnetic diffusivity

β

. These coefficients were modeled using three complementary theoretical approaches. [...] Read more.

We investigate the

α

and

β

effects in a rotating spherical plasma system relevant to astrophysical contexts. In particular, we focus on how kinetic and magnetic (current) helicities influence the magnetic diffusivity

β

. These coefficients were modeled using three complementary theoretical approaches. Direct numerical simulation (DNS) data (large-scale magnetic field

\bar{B}

, turbulent velocity

u

, and turbulent magnetic field

b

) were then used to obtain the actual values of

α_{EM - HM}

,

β_{EM - HM}

,

β_{vv - vw}

, and

β_{bb + jb}

. Using these coefficients, we reconstructed

\bar{B}

and compared it with the DNS results. In the kinematic regime, where

\bar{B}

remains weak, all models agree well with DNS. In the nonlinear regime, however, the field reconstructed with

β_{vv - vw}

alone deviates from DNS and grows without bound. Incorporating the turbulent magnetic diffusion term

β_{bb + jb}

suppresses this unphysical growth and restores consistency. Specifically,

{\bar{B}}_{D N S}

saturates at approximately 0.23 in the nonlinear regime. The reconstructed

\bar{B}

using

β_{E M - H M}

saturates at

\bar{B}

∼0.3. When

β_{v v - v w + b b + j b}

(= β_{v v - v w} + β_{b b + j b})

is used,

\bar{B}

varies from about 0.3 to 0.23. These results indicate that kinetic helicity reduces

β

(or provides a negative contribution), thereby amplifying

\bar{B}

, whereas turbulent current helicity, together with turbulent magnetic and kinetic energies, enhances

β

, thus suppressing

\bar{B}

in the nonlinear regime. In this respect, the new form of

β

differs from the conventional one, which acts solely to diffuse the magnetic field. Full article

(This article belongs to the Special Issue Particles and Plasmas in Strong Fields)

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15 pages, 11792 KB

Open AccessArticle

A Nanosatellite-Sized Detector for Sub-MeV Charged Cosmic Ray Fluxes in Low Earth Orbit: The Low-Energy Module (LEM) Onboard the NUSES Space Mission

by Riccardo Nicolaidis, Andrea Abba, Domenico Borrelli, Adriano Di Giovanni, Luigi Ferrentino, Giovanni Franchi, Francesco Nozzoli, Giancarlo Pepponi, Lorenzo Perillo, David Schledewitz and Enrico Verroi

Particles 2025, 8(4), 97; https://doi.org/10.3390/particles8040097 - 4 Dec 2025

Viewed by 179

Abstract

NUSES is a planned space mission aiming to test new observational and technological approaches related to the study of low-energy cosmic rays, gamma rays, and high-energy astrophysical neutrinos. Two scientific payloads will be hosted onboard the NUSES space mission: Terzina and Zirè. Terzina [...] Read more.

NUSES is a planned space mission aiming to test new observational and technological approaches related to the study of low-energy cosmic rays, gamma rays, and high-energy astrophysical neutrinos. Two scientific payloads will be hosted onboard the NUSES space mission: Terzina and Zirè. Terzina will be an optical telescope readout by SiPM arrays for the detection and study of Cerenkov light emitted by Extensive Air Showers (EASs) generated by high-energy cosmic rays and neutrinos in the atmosphere. Zirè will focus on the detection of protons and electrons up to a few hundred MeV and 0.1–30 MeV photons and will include the Low-Energy Module (LEM). The LEM will be a particle spectrometer devoted to the observation of fluxes of low-energy electrons in the 0.1–7-MeV range and protons in the 3–50 MeV range in low Earth orbit (LEO) followed by the hosting platform. The detection of Particle Bursts (PBs) in this physics channel of interest could provide insights into understanding complex phenomena such as possible correlations between seismic events or volcanic activity with the collective motion of particles in the plasma populating Van Allen belts. With its compact size and limited acceptance, the LEM will allow the exploration of hostile environments such as the South Atlantic Anomaly (SAA) and the inner Van Allen belt, in which the anticipated electron fluxes are on the order of

10^{6}

to

10^{7}

electrons per square centimeter per steradian per second. Concerning the vast literature on space-based particle spectrometers, the innovative aspect of the LEM resides in its compactness, within

10 \times 10 \times 10

cm³, and in its “active collimation” approach to dealing with the problem of multiple scattering at these low energies. In this work, the geometry of the detector, its detection concept, its operation modes, and the hardware adopted will be presented. Some preliminary results from a Monte Carlo simulation (Geant4) will be shown. Full article

(This article belongs to the Special Issue Advances in Space AstroParticle Physics: Frontier Technologies for Particle Measurements in Space, 2025 Edition)

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10 pages, 501 KB

Open AccessArticle

Simulation of a SiPM-Based Cherenkov Camera

by Isaac Buckland, Riccardo Munini and Valentina Scotti

Particles 2025, 8(4), 96; https://doi.org/10.3390/particles8040096 - 3 Dec 2025

Viewed by 141

Abstract

Future space detectors for Ultra High Energy neutrinos and cosmic rays will utilize Cherenkov telescopes to detect forward-beamed Cherenkov light produced by charged particles in Extensive Air Showers (EASs). A Cherenkov detector can be equipped with an array of Silicon Photo-Multiplier (SiPM) pixels, [...] Read more.

Future space detectors for Ultra High Energy neutrinos and cosmic rays will utilize Cherenkov telescopes to detect forward-beamed Cherenkov light produced by charged particles in Extensive Air Showers (EASs). A Cherenkov detector can be equipped with an array of Silicon Photo-Multiplier (SiPM) pixels, which offer several advantages over traditional Photo-Multiplier Tubes (PMTs). SiPMs are compact and lightweight and operate at lower voltages, making them well-suited for space-based experiments. The SiSMUV (SiPM-based Space Monitor for UV-light) is developing a SiPM-based Cherenkov camera for PBR (POEMMA Baloon with Radio) at INFN Napoli. To understand the response of such an instrument, a comprehensive simulation of the response of individual SiPM pixels to incident light is needed. For the accurate simulation of a threshold trigger, this simulation must reproduce the current produced by a SiPM pixel as a function of time. Since a SiPM pixel is made of many individual Avalanche Photo-Diodes (APDs), saturation and pileup in APDs must also be simulated. A Gaussian mixture fit to ADC count spectrum of a SiPM pixel exposed to low levels of laser light at INFN Napoli shows a significant amount of samples between the expected PE (Photo Electron) peaks. Thus, noise sources such as dark counts and afterpulses, which result in partially integrated APD pulses, must be accounted for. With static, reasonable values for noise rates, the simulation chain presented in this work uses the characteristics of individual APDs to produce the aggregate current produced by a SiPM pixel. When many such pulses are simulated and integrated, the ADC spectra generated by low levels of laser light at the INFN Napoli SiSMUV test setup can be accurately reproduced. Full article

(This article belongs to the Special Issue Advances in Space AstroParticle Physics: Frontier Technologies for Particle Measurements in Space, 2025 Edition)

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16 pages, 301 KB

Open AccessArticle

Discovering the Underlying Analytic Structure Within Standard Model Constants Using Artificial Intelligence

by Sergei V. Chekanov and Håkan Kjellerstrand

Particles 2025, 8(4), 95; https://doi.org/10.3390/particles8040095 - 29 Nov 2025

Viewed by 583

Abstract

This paper presents a method for uncovering hidden analytic relationships among the fundamental parameters of the Standard Model (SM), a foundational theory in physics that describes the fundamental particles and their interactions, using symbolic regression and genetic programming. Using this approach, we identify [...] Read more.

This paper presents a method for uncovering hidden analytic relationships among the fundamental parameters of the Standard Model (SM), a foundational theory in physics that describes the fundamental particles and their interactions, using symbolic regression and genetic programming. Using this approach, we identify the simplest analytic relationships connecting pairs of these constants and report several notable expressions obtained with relative precision better than 1%. These results may serve as valuable inputs for model builders and artificial intelligence methods aimed at uncovering hidden patterns among the SM constants, or potentially used as building blocks for a deeper underlying law that connects all parameters of the SM through a small set of fundamental constants. Full article

(This article belongs to the Section Computational and Mathematical Physics, AI and Machine Learning)

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11 pages, 1570 KB

Open AccessArticle

A SiPM-Based RICH Detector with Timing Capabilities for Isotope Identification

by Mario Nicola Mazziotta, Liliana Congedo, Giuseppe De Robertis, Mario Giliberti, Francesco Licciulli, Antonio Liguori, Leonarda Lorusso, Nicola Nicassio, Giuliana Panzarini and Roberta Pillera

Particles 2025, 8(4), 94; https://doi.org/10.3390/particles8040094 - 28 Nov 2025

Viewed by 300

Abstract

In this work, we present a novel compact particle identification (PID) detector concept based on Silicon Photomultipliers (SiPMs) optimized to perform combined Ring-Imaging Cherenkov (RICH) and Time-of-Flight (TOF) measurements using a common photodetector layer. The system consists of a Cherenkov radiator layer separated [...] Read more.

In this work, we present a novel compact particle identification (PID) detector concept based on Silicon Photomultipliers (SiPMs) optimized to perform combined Ring-Imaging Cherenkov (RICH) and Time-of-Flight (TOF) measurements using a common photodetector layer. The system consists of a Cherenkov radiator layer separated from a photosensitive surface equipped with SiPMs by an expansion gap. A thin glass slab, acting as a second Cherenkov radiator, is coupled to the SiPMs to perform Cherenkov-based charged particle timing measurements. We assembled a small-scale prototype instrumented with various Hamamatsu SiPM array sensors with pixel pitches ranging from 2 to 3 mm and coupled with 1 mm thick fused silica window. The RICH radiator consisted of a 2 cm thick aerogel tile with a refractive index of 1.03 at 400 nm. The prototype was successfully tested in beam test campaigns at the CERN PS T10 beam line with pions and protons. We measured a single-hit angular resolution of about 4 mrad at the Cherenkov angle saturation value and a time resolution better than 50 ps RMS for charged particles with Z = 1. The present technology makes the proposed SiPM-based PID system particularly attractive for space applications due to the limited detector volumes available. In this work, we present beam test results obtained with the detector prototype and we discuss possible configurations optimized for the identification of ions in space applications. Full article

(This article belongs to the Special Issue Advances in Space AstroParticle Physics: Frontier Technologies for Particle Measurements in Space, 2025 Edition)

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9 pages, 1179 KB

Open AccessArticle

The Scintillating Fiber Tracker of the Ziré Detector Onboard the NUSES Space Mission

by Felicia Carla Tiziana Barbato, Ivan De Mitri, Giuseppe De Robertis, Adriano Di Giovanni, Leonardo Di Venere, Giulio Fontanella, Fabio Gargano, Mario Giliberti, Francesco Licciulli, Antonio Liguori, Francesco Loparco, Leonarda Lorusso, Mario Nicola Mazziotta, Giuliana Panzarini, Roberta Pillera, Pierpaolo Savina and Aleksei Smirnov

Particles 2025, 8(4), 93; https://doi.org/10.3390/particles8040093 - 28 Nov 2025

Viewed by 215

Abstract

NUSES is a pathfinder satellite that will be deployed in a low Earth orbit, designed with new technologies for space-based detectors. Ziré is one of the payloads of NUSES and aims to measure the spectra of electrons, protons, and light nuclei in a [...] Read more.

NUSES is a pathfinder satellite that will be deployed in a low Earth orbit, designed with new technologies for space-based detectors. Ziré is one of the payloads of NUSES and aims to measure the spectra of electrons, protons, and light nuclei in a kinetic energy range spanning from a few MeVs to several hundred MeVs, as well as photons in the energy range from 0.1 MeV to 30 MeV. Ziré consists of a Fiber TracKer (FTK), a Plastic Scintillator Tower (PST), a calorimeter (CALOg), an AntiCoincidence System (ACS) and a Low Energy Module (LEM). The FTK is based on thin scintillating fibers read out by Silicon Photomultiplier (SiPM) arrays. We assembled a prototype of Ziré (Zirettino) equipped with a single FTK layer, a reduced number of PST layers and a partially instrumented CALOg. A preliminary version of the Ziré custom Front-End Board (FEB) featuring the on-the-shelf ASIC CITIROC by OMEGA/Weeroc was used for the readout. We carried out several beam test campaigns at CERN’s PS facility and a dynamic qualification test. The performance of FTK will be presented and discussed. Full article

(This article belongs to the Special Issue Advances in Space AstroParticle Physics: Frontier Technologies for Particle Measurements in Space, 2025 Edition)

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9 pages, 6288 KB

Open AccessArticle

The SiSMUV Project: Development and Characterization of SiPM-Based UV-Light Detectors for Space Telescope Applications

by Valentina Scotti, Giuseppe Osteria, Marco Mese, Antonio Anastasio, Alfonso Boiano, Isaac Buckland, Vincenzo Masone, Riccardo Munini, Beatrice Panico and Haroon Akhtar Qureshi

Particles 2025, 8(4), 92; https://doi.org/10.3390/particles8040092 - 27 Nov 2025

Viewed by 228

Abstract

The study of Ultra-High-Energy Cosmic Rays is made possible by space telescopes that allow for the recording of signals generated by Extensive Air Showers (EAS) on the night side of the Earth’s atmosphere. One of the requirements for these telescopes is the detection [...] Read more.

The study of Ultra-High-Energy Cosmic Rays is made possible by space telescopes that allow for the recording of signals generated by Extensive Air Showers (EAS) on the night side of the Earth’s atmosphere. One of the requirements for these telescopes is the detection of very low photon fluxes, achievable using the latest generation SiPMs characterized by high intrinsic gains, low power consumption, low weight, and robustness against accidental exposure to light. Despite these advantages, some technological issues still need to be addressed, such as the radiation hardness for operation in space. Therefore, the design of a SiPM-based focal surface for UHECR detection must consider the space qualification of SiPM arrays, with the development of compact arrays optimized for low dead-area focal surfaces. SiSMUV (SiPM-based Space Monitor for UV light) is a project dedicated to developing a compact and modular UV detector for use in space telescopes designed to study the fluorescence and Cherenkov signals produced by Ultra-High-Energy Cosmic Rays (UHECRs). Each SiSMUV module incorporates a matrix of SiPMs, a readout ASIC (Radioroc by Weeroc), and an FPGA into a monolithic block. This design enables the acquisition and processing of signals from the sensors. The system can connect to a PC for standalone operation or with back-end electronics for integration into more complex systems. In this paper, we will describe the prototype electronics, the experimental setup and the measurements performed to obtain parameters such as the gain of the SiPMs, and their photon detection efficiency (PDE). We will also present the firmware developed to interface with the readout ASIC and to transmit data to other peripherals. Full article

(This article belongs to the Special Issue Advances in Space AstroParticle Physics: Frontier Technologies for Particle Measurements in Space, 2025 Edition)

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8 pages, 886 KB

Open AccessArticle

Advanced Readout Logic for the XGIS Instrument: Discriminating X-Ray and Gamma-Ray Photons from the Background and Particles

by Paolo Calabretto, Claudio Labanti, Enrico Virgilli, Lorenzo Amati, Riccardo Campana, Giulia Mattioli, Smiriti Srivastava, Ezequiel J. Marchesini, Edoardo Borciani, Ajay Sharma, Giovanni La Rosa, Paolo Nogara, Giuseppe Sottile and Alfonso Pisapia

Particles 2025, 8(4), 91; https://doi.org/10.3390/particles8040091 - 22 Nov 2025

Viewed by 203

Abstract

The X and Gamma Imager and Spectrometer (XGIS) on board THESEUS is a finely pixelized and modular instrument designed for broadband high-energy transient detection. XGIS consists of two cameras, each composed of 10 supermodules, with each supermodule further divided into 10 modules and [...] Read more.

The X and Gamma Imager and Spectrometer (XGIS) on board THESEUS is a finely pixelized and modular instrument designed for broadband high-energy transient detection. XGIS consists of two cameras, each composed of 10 supermodules, with each supermodule further divided into 10 modules and each module made with 64 independent readout pixels based on Silicon Drift Detectors coupled with 5 × 5 × 30 mm³ CsI scintillator bars. An algorithm to quickly read out the signals from the 64 pixels and send them in chronological order through the module and supermodule logic up to the camera logic is under development. Furthermore, a challenge for space-based high-energy instruments is distinguishing X-/gamma-ray photons while effectively rejecting background photons and particles, including electrons, protons, and heavier cosmic rays. Unlike traditional systems that rely on anticoincidence systems, XGIS aims to achieve background rejection through an innovative readout logic that analyzes the spatial and temporal properties of energy deposits in the detector. By leveraging the finely pixelized structure, the readout system can differentiate single-photon events from charged-particle tracks based on energy deposition patterns and event topology. Full article

(This article belongs to the Special Issue Advances in Space AstroParticle Physics: Frontier Technologies for Particle Measurements in Space, 2025 Edition)

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7 pages, 2053 KB

Open AccessArticle

The Cherenkov Camera for the PBR Mission

by Beatrice Panico, Roberto Ammendola, Antonio Anastasio, Davide Badoni, Mario Bertaina, Francesco Cafagna, Donatella Campana, Marco Casolino, Cristian De Santis, Andrea Di Salvo, Raffaele Gargiulo, Alessandro Marcelli, Laura Marcelli, Vincenzo Masone, Marco Mese, Marco Mignone, Giuseppe Osteria, Giuseppe Passeggio, Francesco Perfetto, Haroon Akhtar Qureshi, Enzo Reali, Ester Ricci and Valentina Scotti Show full author list Hide full author list

Particles 2025, 8(4), 90; https://doi.org/10.3390/particles8040090 - 21 Nov 2025

Viewed by 211

Abstract

POEMMA-Balloon with Radio (PBR) is designed as a payload for a NASA suborbital Super Pressure Balloon that will circle over the Southern Ocean and a mission duration as long as 50 days. The PBR instrument consists of a 1.1 m aperture Schmidt telescope [...] Read more.

POEMMA-Balloon with Radio (PBR) is designed as a payload for a NASA suborbital Super Pressure Balloon that will circle over the Southern Ocean and a mission duration as long as 50 days. The PBR instrument consists of a 1.1 m aperture Schmidt telescope similar to the POEMMA design with two cameras in its focal surface: a Fluorescence Camera (FC) and a Cherenkov Camera (CC). The CC camera is mainly devoted to the observation of cosmic-ray-induced high-altitude horizontal air showers (HAHAs) and search for neutrino-induced upward-going EAS. It will be made of 2048 SiPMs with a surface of 3 × 3 mm² and a FoV of 12° by 6°, covering a spectral range of 320–900 nm. The CC camera is an innovative detector currently under construction. In this paper, information about its current status will be given. Full article

(This article belongs to the Special Issue Advances in Space AstroParticle Physics: Frontier Technologies for Particle Measurements in Space, 2025 Edition)

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11 pages, 11296 KB

Open AccessArticle

Design of the ANTARES4 Readout ASIC for the Second Flight of the GAPS Experiment: Motivations and Requirements

by Luca Ghislotti, Paolo Lazzaroni, Massimo Manghisoni and Elisa Riceputi

Particles 2025, 8(4), 89; https://doi.org/10.3390/particles8040089 - 15 Nov 2025

Viewed by 262

Abstract

The General AntiParticle Spectrometer is a balloon-borne experiment designed to search for low-energy cosmic-ray antinuclei as a potential indirect signature of dark matter. Over the course of at least three long-duration flights over Antarctica, it will explore the sub- [...] Read more.

The General AntiParticle Spectrometer is a balloon-borne experiment designed to search for low-energy cosmic-ray antinuclei as a potential indirect signature of dark matter. Over the course of at least three long-duration flights over Antarctica, it will explore the sub-

250 M e V / n

energy range with sensitivity to antideuterons and antihelium, while also extending antiproton measurements below 100

M

e V

. The instrument features a tracker built from more than one thousand lithium-drifted silicon detectors, each read out by a dedicated custom integrated circuit. With the first flight scheduled for the austral summer of 2025, a new prototype chip, ANTARES4, has been developed using a commercial 65

n

m

complementary metal-oxide semiconductor process for use in the second flight. It integrates eight independent analog channels, each incorporating a low-noise charge-sensitive amplifier with dynamic signal compression, a CR–RC shaping stage with eight selectable peaking times, and on-chip calibration circuitry. The charge-sensitive amplifier uses metal-oxide semiconductor feedback elements with voltage-dependent capacitance to support the wide input energy range from 10

k

e V

to 100

M

e V

. Four alternative feedback implementations are included to compare performance and design trade-offs. Leakage current compensation up to 200

n

A

per detector strip is provided by a Krummenacher current–feedback network. This paper presents the design and architecture of ANTARES4, highlighting the motivations, design drivers, and performance requirements that guided its development. Full article

(This article belongs to the Special Issue Advances in Space AstroParticle Physics: Frontier Technologies for Particle Measurements in Space, 2025 Edition)

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20 pages, 423 KB

Open AccessArticle

Study of the ρ⁰ Decay into π⁰π⁰γ Within Framework of Chiral Perturbation Theory with Resonances

by José A. Barajas-Aguilar, Francisco V. Flores-Baez and José R. Morones-Ibarra

Particles 2025, 8(4), 88; https://doi.org/10.3390/particles8040088 - 11 Nov 2025

Viewed by 289

Abstract

In this work, we calculate the Branching Ratio (BR) of the process

ρ^{0} \to π^{0} π^{0} γ

at tree level within the theoretical framework of with resonances, including the odd intrinsic parity sector. Owing to the nature of an effective [...] Read more.

In this work, we calculate the Branching Ratio (BR) of the process

ρ^{0} \to π^{0} π^{0} γ

at tree level within the theoretical framework of with resonances, including the odd intrinsic parity sector. Owing to the nature of an effective field theory, the BR depends on three unknown couplings of the model:

d_{4}

and the combination

c_{57} = c_{5} + c_{7}

. To constrain these unknown couplings, we use the experimental BR of this decay and explore the possibility of reducing the number of unknown couplings through the on-shell condition at one vertex. Our result suggests that off-shell conditions must be applied to both vertices, leading to a space parameter for the pair (

c_{57}, d_{4}

). Full article

(This article belongs to the Section Nuclear and Hadronic Theory)

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9 pages, 1052 KB

Open AccessArticle

Advanced Particle Classification in Space Calorimetry Using Transformer-Based and Gradient Boosting Models

by Maria Bossa, Federica Cuna and Fabio Gargano

Particles 2025, 8(4), 87; https://doi.org/10.3390/particles8040087 - 5 Nov 2025

Viewed by 415

Abstract

Artificial intelligence has made remarkable progress across numerous domains, including physics, where machine learning and deep learning methods have become increasingly common. In high-energy physics, these approaches have significantly advanced tasks like event reconstruction, pattern recognition, and large-scale data analysis. The present study [...] Read more.

Artificial intelligence has made remarkable progress across numerous domains, including physics, where machine learning and deep learning methods have become increasingly common. In high-energy physics, these approaches have significantly advanced tasks like event reconstruction, pattern recognition, and large-scale data analysis. The present study explores the application of machine learning techniques to the classification of electromagnetic and hadronic showers in space calorimeter experiments. Leveraging Monte Carlo simulations and a dedicated feature engineering, the findings demonstrate the strong potential of AI to improve classification performance in space calorimetry. Full article

(This article belongs to the Special Issue Advances in Space AstroParticle Physics: Frontier Technologies for Particle Measurements in Space, 2025 Edition)

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9 pages, 2093 KB

Open AccessArticle

A Cosmic Radiation Modular Telescope on the Moon: The MoonRay Concept

by Pier Simone Marrocchesi

Particles 2025, 8(4), 86; https://doi.org/10.3390/particles8040086 - 27 Oct 2025

Viewed by 412

Abstract

The MoonRay project is carrying out a concept study of a permanent lunar cosmic-ray (CR) and gamma-ray observatory, in view of the implementation of habitats on our satellite. The idea is to build a modular telescope that will be able to overcome the [...] Read more.

The MoonRay project is carrying out a concept study of a permanent lunar cosmic-ray (CR) and gamma-ray observatory, in view of the implementation of habitats on our satellite. The idea is to build a modular telescope that will be able to overcome the limitations, in available power and weight, of the present generation of CR instruments in Low Earth Orbit, while carrying out high-energy gamma-ray observations from a vantage point at the South Pole of the Moon. An array of fully independent modules (towers), with limited individual size and mass, can provide an acceptance more than one order of magnitude larger than instruments in flight at present. The modular telescope is designed to be deployed progressively, during a series of lunar missions, while collecting meaningful scientific data at the intermediate stages of its implementation. The operational power will be made available by the facilities maintaining the lunar habitats. With a geometric factor close to 15 m²sr and about 8 times larger sensitive area than FERMI-LAT, MoonRay will be able to carry out a very rich observational program over a time span of a few decades with an energy reach of 10 PeV allowing the exploration of the CR “knee” and the observation of the Southern Sky with gamma rays well into the TeV scale. Each tower (of approximate size 20 cm × 20 cm ×100 cm) is equipped with three instruments. A combined Charge and Time-of-Flight detector (CD-ToF) can identify individual cosmic elements, leveraging on an innovative two-layered array of pixelated Low-Gain Avalanche Diode (LGAD) sensors, with sub-ns time resolution. The latter can achieve an unprecedented rejection power against backscattered radiation from the calorimeter. It is followed by a tracker, providing also photon conversion, and by a thick crystal calorimeter (55 radiation lengths, 3 proton interaction lengths at normal incidence) with an energy resolution of 30–40% (1–2%) for protons (electrons) and a proton/electron rejection in excess of 10⁵. A time resolution close to 100 ps has been obtained, with prototypal arrays of 3 mm × 3 mm LGAD pixels, in a recent test campaign carried out at CERN with Pb beam fragments. Full article

(This article belongs to the Special Issue Advances in Space AstroParticle Physics: Frontier Technologies for Particle Measurements in Space, 2025 Edition)

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18 pages, 1790 KB

Open AccessArticle

The Kaon Off-Shell Generalized Parton Distributions and Transverse Momentum Dependent Parton Distributions

by Jin-Li Zhang

Particles 2025, 8(4), 85; https://doi.org/10.3390/particles8040085 - 25 Oct 2025

Viewed by 538

Abstract

We investigate the off-shell generalized parton distributions (GPDs) and transverse momentum dependent parton distributions (TMDs) of kaons within the framework of the Nambu–Jona-Lasinio model, employing proper time regularization. Compared to the pion case, the off-shell effects in kaons are of similar magnitude, modifying [...] Read more.

We investigate the off-shell generalized parton distributions (GPDs) and transverse momentum dependent parton distributions (TMDs) of kaons within the framework of the Nambu–Jona-Lasinio model, employing proper time regularization. Compared to the pion case, the off-shell effects in kaons are of similar magnitude, modifying the GPDs by about 10–

25 %

, which is notable. The absence of crossing symmetry leads to odd powers in the x-moments of the off-shell GPDs, giving rise to new off-shell form factors. We analyze the relations among these kaon off-shell form factors by analogy with electromagnetic form factors. Our results extend the off-shell GPDs from pions to kaons and simultaneously address the associated off-shell form factors. We also compare the off-shell and on-shell gravitational form factors of the kaon. In addition, the off-shell kaon TMD shows a stronger dependence on the momentum fraction x than its on-shell counterpart. Full article

(This article belongs to the Special Issue Strong QCD and Hadron Structure)

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11 pages, 440 KB

Open AccessArticle

Pre-Supernova (Anti)Neutrino Emission Due to Weak-Interaction Reactions with Hot Nuclei

by Alan A. Dzhioev, Andrey V. Yudin, Natalia V. Dunina-Barkovskaya and Andrey I. Vdovin

Particles 2025, 8(4), 84; https://doi.org/10.3390/particles8040084 - 12 Oct 2025

Viewed by 489

Abstract

Reliable predictions of (anti)neutrino spectra and luminosities are essential for assessing the feasibility of detecting pre-supernova neutrinos. Using the stellar evolution code MESA, we calculate the (anti)neutrino spectra and luminosities under realistic conditions of temperature, density, and electron fraction. Our study includes (anti)neutrinos [...] Read more.

Reliable predictions of (anti)neutrino spectra and luminosities are essential for assessing the feasibility of detecting pre-supernova neutrinos. Using the stellar evolution code MESA, we calculate the (anti)neutrino spectra and luminosities under realistic conditions of temperature, density, and electron fraction. Our study includes (anti)neutrinos produced by both thermal processes and nuclear weak-interaction reactions. By comparing the results of the thermal quasiparticle random-phase approximation with the standard technique based on the effective Q-value method, we investigate how thermal effects influence the spectra and luminosities of emitted (anti)neutrinos. Our findings show that a thermodynamically consistent treatment of Gamow–Teller transitions in hot nuclei enhances both the energy luminosity and the average energies of the emitted (anti)neutrinos. Full article

(This article belongs to the Special Issue Infinite and Finite Nuclear Matter (INFINUM))

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11 pages, 285 KB

Open AccessArticle

Diquark Study in Quark Model

by Xinmei Zhu, Hongxia Huang and Jialun Ping

Particles 2025, 8(4), 83; https://doi.org/10.3390/particles8040083 - 2 Oct 2025

Viewed by 460

Abstract

To investigate diquark correlation in baryons, the baryon spectra with different light–heavy quark combinations are calculated using Gaussian expansion method within both the naive quark model and the chiral quark model. By computing the diquark energies and separations between any two quarks in [...] Read more.

To investigate diquark correlation in baryons, the baryon spectra with different light–heavy quark combinations are calculated using Gaussian expansion method within both the naive quark model and the chiral quark model. By computing the diquark energies and separations between any two quarks in baryons, we analyze the diquark effect in the

u d

-q/Q,

u s

-Q,

s s

-q/Q, and

Q Q

-q/Q systems (where

q = u, d

, or s;

Q = c, b

). The results show that diquark correlations exist in baryons. In particular, for

q q

-Q and

Q Q

-q systems, the same type of diquark exhibits nearly identical energy and size across different baryons. In the orbital ground states of baryons, scalar–isoscalar diquarks have lower energy and a smaller size compared to vector–isovector diquark, which qualifies them as “good diquarks”. In

Q Q

-q systems, a larger mass of Q leads to a smaller diquark separation and a more pronounced diquark effect. In

q q

-Q systems, the separation between the two light quarks remains larger than that between a light and a heavy quark, indicating that the internal structure of such diquarks must be taken into account. A comparison between the naive quark model and the chiral quark model reveals that the introduction of meson exchange slightly increases the diquark size in most systems. Full article

(This article belongs to the Special Issue Strong QCD and Hadron Structure)

9 pages, 4977 KB

Open AccessArticle

A New Measurement of Light Yield Quenching in EJ-200 and LYSO Scintillators

by Francesco Dimiccoli, Francesco Maria Follega, Luigi Ernesto Ghezzer, Roberto Iuppa, Alessandro Lega, Riccardo Nicolaidis, Francesco Nozzoli, Ester Ricci, Enrico Verroi and Paolo Zuccon

Particles 2025, 8(4), 82; https://doi.org/10.3390/particles8040082 - 30 Sep 2025

Viewed by 889

Abstract

Lutetium–Yttrium Oxyorthosilicate (LYSO) crystals and EJ-200 plastic scintillators are widely recognized fast scintillating materials, valued for their high light yield and mechanical robustness, which make them well suited for demanding applications in high-energy physics and space research. Their non-proportional light response, along with [...] Read more.

Lutetium–Yttrium Oxyorthosilicate (LYSO) crystals and EJ-200 plastic scintillators are widely recognized fast scintillating materials, valued for their high light yield and mechanical robustness, which make them well suited for demanding applications in high-energy physics and space research. Their non-proportional light response, along with their non-linear behavior at low-energy X-rays, has been extensively investigated in previous studies, revealing potential systematic effects in existing measurements. In this work, light quenching in both scintillators is measured under charged-particle excitation. The results are interpreted using the modified Birks–Onsager model, which provides a theoretical framework for understanding the underlying quenching mechanisms, as well as a generalized logistic parametrization, offering experimentalists a useful tool to characterize the detector’s light yield and associated uncertainties. Full article

(This article belongs to the Special Issue Advances in Space AstroParticle Physics: Frontier Technologies for Particle Measurements in Space, 2025 Edition)

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