Particles

15 pages, 2312 KB

Open AccessArticle

Magnetodynamic Characteristics of QGP Energy Dissipation in RMHD Framework with Relativistic Heavy-Ion Collisions

by Huang-Jing Zheng and Sheng-Qin Feng

Particles 2026, 9(1), 29; https://doi.org/10.3390/particles9010029 - 19 Mar 2026

Viewed by 514

Relativistic heavy-ion collisions generate ultra-strong magnetic fields that interact with the quark–gluon plasma (QGP), a key focus of high-energy physics research. This study investigates QGP energy density evolution under time-dependent magnetic fields within a (1 + 1)D relativistic magnetohydrodynamic (RMHD) framework integrated with [...] Read more.

Relativistic heavy-ion collisions generate ultra-strong magnetic fields that interact with the quark–gluon plasma (QGP), a key focus of high-energy physics research. This study investigates QGP energy density evolution under time-dependent magnetic fields within a (1 + 1)D relativistic magnetohydrodynamic (RMHD) framework integrated with Bjorken flow. Three magnetic field temporal evolution models (Type-1, Type-2, Type-3) are analyzed for two different equations of state: (1)

p = {c_{s}}^{2} e

(simplified ultra-relativistic), and (2)

p = {c_{s}}^{2} e - 2 M B

(magnetized conformal), incorporating a temperature-dependent magnetic susceptibility derived from lattice QCD. Results show that stronger magnetic fields consistently suppress QGP energy density decay, with suppression magnitude dependent on the magnetic field’s temporal profile. Ultra-relativistic fluids exhibit slowed energy decay due to magnetic pressure counteracting hydrodynamic expansion. In contrast, magnetized conformal fluids display faster energy dissipation under identical conditions, arising from the synergistic effect of enhanced magnetic fluid coupling, increased energy dissipation during interaction, and QGP’s perfect fluid expansion at elevated temperatures. Temperature-dependent magnetic susceptibility reveals a transition from diamagnetic (confined phase) to paramagnetic (deconfined QGP phase) behavior, introducing a feedback mechanism that strengthens energy retention at higher temperatures. This work clarifies the interplay between magnetic field dynamics, QCD phase structure, and hydrodynamic expansion, providing key observational signatures for distinguishing fluid types in heavy-ion collisions and advancing realistic modeling of magnetized QGP. Full article

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10 pages, 1957 KB

Open AccessArticle

Nanofusion: Plasmons Help to Accelerate Protons

by Tamás Biró

Particles 2026, 9(1), 28; https://doi.org/10.3390/particles9010028 - 19 Mar 2026

Viewed by 589

Abstract

We report on laser fusion research with nanotechnology-improved targets embedded in special polymers. The results of the last three years are reviewed here, including laser matter interaction craters, laser infrared breakdown spectroscopy, and Raman spectroscopy results, as well as a selected Thomson parabola [...] Read more.

We report on laser fusion research with nanotechnology-improved targets embedded in special polymers. The results of the last three years are reviewed here, including laser matter interaction craters, laser infrared breakdown spectroscopy, and Raman spectroscopy results, as well as a selected Thomson parabola image showing protons accelerated up to 300 keV. In this paper, we focus on proton acceleration and plasmonic enhancement mechanisms rather than on the direct demonstration of sustained fusion reactions. Full article

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

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28 pages, 5327 KB

Open AccessReview

Halos and Multineutron Correlations in Light Neutron-Rich Nuclei

by Zheyang Lin and Zaihong Yang

Particles 2026, 9(1), 27; https://doi.org/10.3390/particles9010027 - 16 Mar 2026

Cited by 1 | Viewed by 840

Abstract

This review summarizes recent experimental progress in the structure and correlations of light neutron-rich nuclei. We first highlight achievements based on quasi-free scattering reactions in inverse kinematics at the Radioactive Isotope Beam Factory (RIBF), including investigations of the single-particle composition of halo systems—for [...] Read more.

This review summarizes recent experimental progress in the structure and correlations of light neutron-rich nuclei. We first highlight achievements based on quasi-free scattering reactions in inverse kinematics at the Radioactive Isotope Beam Factory (RIBF), including investigations of the single-particle composition of halo systems—for example, revealing the minimal s-wave component in the “weak-halo” nucleus ¹⁷B—and the mapping of universal, surface-localized dineutron correlations in Borromean nuclei such as ¹¹Li, ¹⁴Be and ¹⁷B. We then discuss recent advances in the study of multineutron correlations and cluster states, addressing both experimental challenges and major breakthroughs. These include the observation of a candidate

4 n

resonance, the absence of a resonant state in the

3 n

system, the characterization of direct two-neutron decay in ¹⁶Be, and evidence for a condensate-like

α + {}^{2}n + {}^{2}n

cluster structure in the

{}^{8}{He} (0_{2}^{+})

state. Finally, we discuss prospects for extending such investigations to heavier halo candidates and more complex multineutron systems, and outline the development of next-generation neutron detector arrays that will drive future progress in this field. Full article

(This article belongs to the Special Issue Selected Papers from the International Symposium Commemorating the 40th Anniversary of Halo Nuclei)

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11 pages, 5650 KB

Open AccessArticle

Measurement of Elastic Scattering Angular Distributions for Proton-Rich Nuclei ^21,22Na on Double-Magic Nucleus ⁴⁰Ca

by Yuwen Chen, Wei Nan, Bing Guo, Chengjian Lin, Bing Tang, Danyang Pang, Lei Yang, Dongxi Wang, Guo Yang, Yangping Shen, Qiwen Fan, Yiwen Bao, Lei Cao, Lihua Chen, Baoqun Cui, Yueming Hu, Qinghua Huang, Huiming Jia, Chaoxin Kan, Kangning Li, Yaoqian Li, Yunju Li, Zhihong Li, Gang Lian, Junhui Liao, Zhenwei Liu, Tianpeng Luo, Nanru Ma, Ruigang Ma, Xie Ma, Yingjun Ma, Guofang Song, Lei Wang, Xiaofei Wang, Youbao Wang, Yuheng Wang, Peiwei Wen, Shengquan Yan, Feng Yang, Sheng Zeng, Yifan Zhang, Tianjue Zhang and Weiping Liu Show full author list Hide full author list

Particles 2026, 9(1), 26; https://doi.org/10.3390/particles9010026 - 13 Mar 2026

Viewed by 954

Abstract

Present and future rare isotope accelerator facilities provide new opportunities to explore the structure of unstable nuclei. We report the measurements of the elastic scattering angular distributions of ²¹Na and ²²Na on the doubly magic ⁴⁰Ca above the Coulomb barrier [...] Read more.

Present and future rare isotope accelerator facilities provide new opportunities to explore the structure of unstable nuclei. We report the measurements of the elastic scattering angular distributions of ²¹Na and ²²Na on the doubly magic ⁴⁰Ca above the Coulomb barrier energies, using high-purity post-accelerated ISOL beams from Beijing Radioactive Ion Beam Facility (BRIF). Angular distributions were measured with a silicon detector telescope array, and relative cross sections were determined with a CaF₂ target on Au backing. The data were well reproduced by optical model calculations with Woods–Saxon and USNP potentials, the latter giving better agreement. These results confirm the stable operation and performance of the BRIF ISOL production and post-acceleration system, demonstrate its capability to provide radioactive beams of useful intensity and purity for future investigations of reaction dynamics and astrophysically relevant processes involving proton-rich nuclei, and simultaneously extend proton-rich elastic scattering studies to heavier systems. Full article

(This article belongs to the Special Issue Selected Papers from the International Symposium Commemorating the 40th Anniversary of Halo Nuclei)

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8 pages, 463 KB

Open AccessArticle

Ab Initio Study on the Halo Structure in ¹¹Be

by Shihang Shen, Serdar Elhatisari, Dean Lee, Ulf-G. Meißner and Zhengxue Ren

Particles 2026, 9(1), 25; https://doi.org/10.3390/particles9010025 - 10 Mar 2026

Cited by 1 | Viewed by 796

Abstract

We present an ab initio study on the one-neutron halo nucleus ¹¹Be using nuclear lattice effective field theory with high-fidelity chiral interactions at N3LO. By employing the wavefunction matching method to mitigate the sign problem and the pinhole algorithm to sample many-body [...] Read more.

We present an ab initio study on the one-neutron halo nucleus ¹¹Be using nuclear lattice effective field theory with high-fidelity chiral interactions at N3LO. By employing the wavefunction matching method to mitigate the sign problem and the pinhole algorithm to sample many-body correlations, we successfully reproduce the ground-state parity inversion and the extended matter radius characteristic of the halo structure. We analyze the intrinsic density distributions and geometric shapes of ¹¹Be in comparison with the core nucleus ¹⁰Be. Our results reveal a prominent two-cluster structure in both nuclei and the occupation of the

σ

molecular orbital by the valence neutron in ¹¹Be. It enhances the prolate deformation as well as the diffuse neutron tail, distinct from the

π

-orbital occupation observed in the ¹⁰Be ground state. Full article

(This article belongs to the Special Issue Selected Papers from the International Symposium Commemorating the 40th Anniversary of Halo Nuclei)

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18 pages, 11426 KB

Open AccessArticle

Performance of the ATLAS Muon Spectrometer Detectors During Run 3 Data-Taking

by Arisa Wada

Particles 2026, 9(1), 24; https://doi.org/10.3390/particles9010024 - 10 Mar 2026

Viewed by 627

Abstract

With the conclusion of proton–proton collision data-taking in 2025, the ATLAS experiment has now integrated a luminosity exceeding 300

{fb}^{- 1}

during the Run 3 period, which began in July 2022 following Long Shutdown 2 (LS2). During LS2, a series of detector [...] Read more.

With the conclusion of proton–proton collision data-taking in 2025, the ATLAS experiment has now integrated a luminosity exceeding 300

{fb}^{- 1}

during the Run 3 period, which began in July 2022 following Long Shutdown 2 (LS2). During LS2, a series of detector upgrades were implemented, including the installation of the New Small Wheel (NSW) in the innermost stations of the Muon Spectrometer end-caps. The ATLAS Muon Spectrometer, the largest muon system ever built at a collider, now comprises both established gaseous detectors—Monitored Drift Tubes, Thin Gap Chambers, and Resistive Plate Chambers—and newer detectors like Micromegas and small-strip TGCs in the NSW. These new systems are now in stable operation following an extensive phase of construction and commissioning, providing enhanced muon tracking and trigger capabilities. This presentation covers the performance of the muon system, focusing on the stability of the established detectors over time, their ability to handle increasing luminosity and associated irradiation levels, and studies on detector aging. Emphasis will be placed on the NSW upgrade, including the strategies adopted for alignment, track reconstruction, and trigger. The performance results presented in this contribution are based on Run 3 data collected up to 2024. 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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53 pages, 1976 KB

Open AccessReview

Fully Heavy Pentaquarks with Jethad: A High-Energy Viewpoint

by Francesco Giovanni Celiberto

Particles 2026, 9(1), 23; https://doi.org/10.3390/particles9010023 - 3 Mar 2026

Viewed by 903

Abstract

We examine the leading-power fragmentation of fully heavy pentaquarks in high-energy hadronic collisions. To this end, we complete the release of the hadron structure-oriented PQ5Q1.0 fragmentation functions by discussing the

P_{5 c}

set and delivering the

P_{5 b}

one. These functions [...] Read more.

We examine the leading-power fragmentation of fully heavy pentaquarks in high-energy hadronic collisions. To this end, we complete the release of the hadron structure-oriented PQ5Q1.0 fragmentation functions by discussing the

P_{5 c}

set and delivering the

P_{5 b}

one. These functions incorporate an improved computation of the initial-scale input for the constituent heavy-quark fragmentation channel, making them particularly suitable for describing both the direct formation of a compact multicharm state and the hadronization from a diquark–antiquark–diquark configuration. For phenomenological applications, we employ the data-validated (sym)Jethad framework to compute and analyze NLL/NLO⁺ semi-inclusive production rates of pentaquark-plus-jet systems at the upcoming HL-LHC and the future FCC. This study marks a further step toward connecting hadronic structure, precision QCD, and the emerging physics of exotic matter. Full article

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

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12 pages, 404 KB

Open AccessArticle

Emergence of the Geometric Contribution to the Superfluid Density in the Inner Crust of Neutron Stars

by Giorgio Almirante

Particles 2026, 9(1), 22; https://doi.org/10.3390/particles9010022 - 2 Mar 2026

Viewed by 647

Abstract

The geometric contribution to superfluid density has been found to be of great importance in the inner crust of neutron stars. In this work we clarify how this contribution arises in the context of a band theory for neutrons. Specifically, we derive the [...] Read more.

The geometric contribution to superfluid density has been found to be of great importance in the inner crust of neutron stars. In this work we clarify how this contribution arises in the context of a band theory for neutrons. Specifically, we derive the dependence of the superfluid density on the magnitude of the pairing gap when the system has many bands cutting the Fermi energy, as is the case for neutrons in the inner crust. Also, in the perturbation theory framework, we find that it is essential to account for corrections to (Bogoliubov) quasi-particle states in order to obtain the geometric contribution. Accounting only for the corrections to (Hartree–Fock) single-particle states leads to the conventional contribution only. Full article

(This article belongs to the Special Issue Selected Papers from “The Modern Physics of Compact Stars and Relativistic Gravity 2025”)

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7 pages, 853 KB

Open AccessBrief Report

Halo Phenomena in Light- to Medium-Mass Nuclei with Three-Body Models

by Lorenzo Fortunato

Particles 2026, 9(1), 21; https://doi.org/10.3390/particles9010021 - 2 Mar 2026

Viewed by 595

Abstract

Short-lived nuclear systems with light to medium masses are showing halo phenomena in regions of the nuclear chart that were still unexplored when halo nuclei were discovered 40 years ago. We study these exotic systems with three-body models, including nucleon–nucleon correlations, with the [...] Read more.

Short-lived nuclear systems with light to medium masses are showing halo phenomena in regions of the nuclear chart that were still unexplored when halo nuclei were discovered 40 years ago. We study these exotic systems with three-body models, including nucleon–nucleon correlations, with the aim of reproducing measurable properties like radii and electromagnetic transition strengths. On the nucleon-rich side, drip-line fluorine isotopes are showing clear signs of a halo structure. Recently, we proposed that

{}^{29}F

is a moderate two-neutron halo nucleus with a large radius and a strong B(E1) response to the continuum. The three-body model places it at the borders of the island of inversion, which is corroborated by new data. According to our models, the next interesting isotope,

{}^{31}F

, also has large spatial extension due to p-wave components and enhanced B(E1) response, pointing to a speculative halo structure. On the proton-rich side, we have studied the

{}^{102}{Sb}

system, composed of a

{}^{100}{Sn}

core plus a proton–neutron-correlated subsystem. We find that the weakening of the proton–neutron correlations with respect to the bare deuteron indicates that this is a one-proton emitter. We propose that the presence of a resonant state and its decay might provide a crucial benchmark for this system. Full article

(This article belongs to the Special Issue Selected Papers from the International Symposium Commemorating the 40th Anniversary of Halo Nuclei)

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15 pages, 1601 KB

Open AccessArticle

Detection of Shielded Nuclear Materials Using Superheated Liquid Detectors

by Leonardo Rodrigues and Miguel Felizardo

Particles 2026, 9(1), 20; https://doi.org/10.3390/particles9010020 - 18 Feb 2026

Viewed by 756

Abstract

Superheated liquid detectors (SLDs) exhibit strong sensitivity to fast neutrons and intrinsic insensitivity to gamma radiation, making them promising candidates for detecting shielded nuclear materials in security and non-proliferation applications. This work evaluates the feasibility of octafluoropropane-based superheated droplet detectors (SDDs) for identifying [...] Read more.

Superheated liquid detectors (SLDs) exhibit strong sensitivity to fast neutrons and intrinsic insensitivity to gamma radiation, making them promising candidates for detecting shielded nuclear materials in security and non-proliferation applications. This work evaluates the feasibility of octafluoropropane-based superheated droplet detectors (SDDs) for identifying neutron-emitting materials concealed behind common attenuators. A combined acoustic and optical readout system was implemented, including a validated pulse-shape analysis method and a machine-learning-based bubble detection algorithm using YOLOv5. The optical system achieved a detection precision of approximately 80% within the defined region of interest. While the acoustic system remains the primary and more mature detection channel, the optical approach demonstrates feasibility but is not yet operationally ready for field deployment. Experiments with an AmBe neutron source and various shielding materials demonstrate that SDDs reliably detect fast neutrons under realistic inspection conditions while remaining insensitive to gamma radiation. These results support the feasibility of SLD-based systems as low-cost, passive tools for detecting shielded nuclear materials in field environments. Full article

(This article belongs to the Section Experimental Physics and Instrumentation)

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13 pages, 13581 KB

Open AccessArticle

POEMMA–Balloon with Radio: A Balloon-Borne Multi- Messenger Multi-Detector Observatory

by Giuseppe Osteria, Johannes Eser and Angela Olinto

Particles 2026, 9(1), 19; https://doi.org/10.3390/particles9010019 - 16 Feb 2026

Viewed by 595

Abstract

The Probe Of Extreme Multi-Messenger Astrophysics (POEMMA) is a proposed dual-satellite mission to observe Ultra-High-Energy Cosmic Rays (UHECRs), increase the statistics at the highest energies, and observe Very-High-Energy Neutrinos (VHENs) following multi-messenger alerts of astrophysical transient events, such as gamma-ray bursts and gravitational [...] Read more.

The Probe Of Extreme Multi-Messenger Astrophysics (POEMMA) is a proposed dual-satellite mission to observe Ultra-High-Energy Cosmic Rays (UHECRs), increase the statistics at the highest energies, and observe Very-High-Energy Neutrinos (VHENs) following multi-messenger alerts of astrophysical transient events, such as gamma-ray bursts and gravitational wave events, throughout the universe. POEMMA–Balloon with radio (PBR) is a small-scale version of the POEMMA design, adapted to be flown as a payload on one of NASA’s suborbital Super Pressure Balloons (SPBs) circling over the Southern Ocean for more than 20 days after a launch from Wanaka, New Zealand. The main science objectives of PBR are: (1) to observe UHECRs via the fluorescence technique from suborbital space; (2) to observe horizontal high-altitude air showers (HAHAs) with energies above the cosmic ray knee (E > 3PeV) using optical and radio detection for the first time; and (3) to follow astrophysical event alerts in the search of VHENs. The PBR instrument consists of a 1.1 m aperture Schmidt telescope similar to the POEMMA design, with two cameras on its focal surface: a Fluorescence Camera (FC) and a Cherenkov Camera (CC). In addition, PBR has a Radio Instrument (RI) optimized for detecting EASs (covering the 60–660 Mhz range). The FC observes UHECR-induced EASs in the ultraviolet (UV) spectrum using an array of 9216-pixel Multi-Anode Photo-Multiplier Tubes (MAPMTs) imaged every 1

μ

s. The CC uses a 2048-pixel Silicon Photo-Multiplier (SiPM) imager to observe cosmic-ray-induced HAHAs and search for neutrino-induced upward-going EASs. The CC covers a spectral range of 320–900 nm, with an integration time of 10 ns. This contribution provides an overview of PBR instruments and their current status. 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, 522 KB

Open AccessReview

Massive Black Hole Formation in Proto-Stellar Clusters via Early Gas Accretion

by Zacharias Roupas

Particles 2026, 9(1), 18; https://doi.org/10.3390/particles9010018 - 15 Feb 2026

Cited by 1 | Viewed by 653

Abstract

In this paper, we review our semi-analytic model of stellar black hole (BH) mass growth via gas accretion in gas-rich stellar clusters during their birthstage within the first ∼

10 Myr

after the first stellar formation event. Such proto-stellar clusters are massive and [...] Read more.

In this paper, we review our semi-analytic model of stellar black hole (BH) mass growth via gas accretion in gas-rich stellar clusters during their birthstage within the first ∼

10 Myr

after the first stellar formation event. Such proto-stellar clusters are massive and compact, with typical masses ∼

10^{6} M_{⊙}

and sizes ∼

1 pc

, as suggested by recent James Webb Space Telescope (JWST) observations. We find that by the end of the gas depletion process, BH masses are shifted to values within and above the BH mass gap, well within the range of components of the recent gravitational-wave (GW) signal GW231123, and up to masses ∼

10^{3} M_{⊙}

. 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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10 pages, 2313 KB

Open AccessArticle

Specular Reflectivity and Diffuse Scattering of Plasma Mirror as a Function of Laser Intensity in Polymer Target

by Imene Benabdelghani, Miklós Ákos Kedves, Ádám Inger and Márk Aladi

Particles 2026, 9(1), 17; https://doi.org/10.3390/particles9010017 - 14 Feb 2026

Viewed by 832

Abstract

We present a systematic study on the optical response of plasma mirrors generated in polymer foils under ultrashort laser pulse irradiation within the non-relativistic intensity regime, reaching up to

2 \times 10^{17}

W/cm². Using a Ti:sapphire system that delivers 50 [...] Read more.

We present a systematic study on the optical response of plasma mirrors generated in polymer foils under ultrashort laser pulse irradiation within the non-relativistic intensity regime, reaching up to

2 \times 10^{17}

W/cm². Using a Ti:sapphire system that delivers 50 fs pulses, we simultaneously measured reflection, transmission, and diffuse scattering with three energy meters for single-shot laser energies of 5, 10, 15, and 20 mJ as a function of the laser spot size on the target. The results reveal intensity-dependent variations in reflectivity, accompanied by simultaneous changes in transmission and scattering, allowing to estimate laser energy absorption by the polymer. Morphological analysis of the plasma surface suggests a significant role in modifying energy absorption, with implications for the efficiency of processes such as laser particle acceleration, nuclear fusion, and attosecond pulse generation. These findings provide critical insights into plasma mirror formation, absorption dynamics in polymers, and the potential of nanostructured polymer targets in high-intensity laser–matter interaction applications. Full article

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

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10 pages, 1845 KB

Open AccessArticle

Preliminary Results of the 64-Channel SiPM Readout MIZAR ASIC

by Andrea Di Salvo, Emanuele Trossarello, Micol Maria Bargelli, Federico Reynaud, Matteo Abrate, Richard Wheadon, Marco Mignone, Angelo Rivetti, Sara Garbolino and Mario Edoardo Bertaina

Particles 2026, 9(1), 16; https://doi.org/10.3390/particles9010016 - 13 Feb 2026

Cited by 1 | Viewed by 727

Abstract

This work describes the development of the Multi-channel Integrated Zone-sampling Analogue-memory based Readout (MIZAR) ASIC. This 64-channel chip was designed as part of NASA’s POEMMA Balloon with RADIO (PBR) mission, which aims to detect Ultra-High-Energy Cosmic Rays (UHECRs) and

τ

showers produced by [...] Read more.

This work describes the development of the Multi-channel Integrated Zone-sampling Analogue-memory based Readout (MIZAR) ASIC. This 64-channel chip was designed as part of NASA’s POEMMA Balloon with RADIO (PBR) mission, which aims to detect Ultra-High-Energy Cosmic Rays (UHECRs) and

τ

showers produced by the interaction of Cosmic Neutrinos (CNs) in the crust. The ASIC was implemented to read out a tile of 8 × 8 Silicon Photomultipliers (SiPMs) used to acquire the optical Cherenkov signals generated by Extensive Air Showers (EASs). A channel is partitioned into 256 cells where each one integrates an analogue memory, a Wilkinson Analog-to-Digital Converter (ADC) and a digital memory operating at the nominal sampling rate of 200 MS/s (with a 5 ns integration time). The signal is digitized on-chip, then the converted data is read out by an FPGA. The MIZAR also provides a 64-bit hitmap as a first-level trigger which can be elaborated by an external firmware. This ASIC can also be configured to further segment the channels into units of 32 or 64 cells each and the ADC resolution can be set to a range between 8 and 12 bits. The chip was designed in a commercial 65 nm CMOS technology node and it was submitted for production in December 2024. The ASICs were delivered in March 2025. 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, 1308 KB

Open AccessArticle

Baryon-like Space Distribution of Dark Matter from Point of View of Explanation of Positron Anomaly

by Konstantin M. Belotsky and Maksim L. Solovev

Particles 2026, 9(1), 15; https://doi.org/10.3390/particles9010015 - 13 Feb 2026

Viewed by 575

Abstract

In this work we test the possibility of accounting for the positron anomaly with annihilating dark matter particles without contradicting the gamma-ray constraints due to their unconventional space distribution. To achieve that, we consider two-component dark matter, whose major constituent is inert and [...] Read more.

In this work we test the possibility of accounting for the positron anomaly with annihilating dark matter particles without contradicting the gamma-ray constraints due to their unconventional space distribution. To achieve that, we consider two-component dark matter, whose major constituent is inert and forms the halo of the Galaxy, while the second, minor, component consists of annihilating particles that could form some different structure. This work is the next logical step after our previous “dark disk model” where an active DM component was considered to form a disk, allowing good suppression of accompanying gamma-radiation. Nowadays that model is not enough to avoid the contradiction, so we are testing a new, more complex one with a spiral spatial distribution like the one of baryons. We have previously tested two simplified toy models of ring-like density profiles and one simple spiral density profile that have shown good improvement compared to the disk case. In this work, we take things further and consider a more physically grounded density profile constructed on the base of a modern model of the baryon density of our Galaxy. Contrary to our expectations, this advanced model shows much worse agreement with the data than previous toy models. Full article

(This article belongs to the Special Issue Selected Papers from XXVIII Workshop “What Comes Beyond the Standard Models?”: New Trends in Particle Cosmology)

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13 pages, 3704 KB

Open AccessArticle

Performance Evaluation of the Readout Electronics Board Based on the Smart Asic for the Adapt Instrument

by Gaia De Palma, Marco Cecca, Leonardo Di Venere, Francesco Licciulli, Mario Nicola Mazziotta, Elisabetta Bissaldi, James Buckley, Blake Bal, Richard Bose and Adrian Zink

Particles 2026, 9(1), 14; https://doi.org/10.3390/particles9010014 - 10 Feb 2026

Viewed by 623

Abstract

The Advanced Particle–astrophysics Telescope (APT) is a mission concept for a future space-based MeV-TeV observatory, designed to combine a Compton and

e^{+} e^{-}

pair telescope, aiming to improve the sensitivity of the instruments to

γ

rays in the MeV-GeV range by [...] Read more.

The Advanced Particle–astrophysics Telescope (APT) is a mission concept for a future space-based MeV-TeV observatory, designed to combine a Compton and

e^{+} e^{-}

pair telescope, aiming to improve the sensitivity of the instruments to

γ

rays in the MeV-GeV range by at least one order of magnitude. To validate and study the technologies that will be employed on the observatory, a small-scale prototype, the Antarctic Demonstrator for APT (ADAPT), is currently being developed to fly on a balloon in Antarctica during the local 2026–2027 flight season. Among its subdetectors there is an Imaging CsI calorimeter (ICC), consisting of 4 layers of CsI(Na) crystals with crossed WLS fibers, coupled to Silicon Photomultipliers (SiPMs). A key element of the design is the multichannel front-end electronics, based on the SMART (SiPM Multichannel ASIC for high-Resolution Cherenkov Telescopes) ASIC, which combines compactness, cost-effectiveness, and a high level of integration. This work reports the results of quality-control tests performed on the custom readout boards for the ICC, and provides an overview of the present status of the mission. 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, 1586 KB

Open AccessArticle

Gamma-RayBurst Polarimetry with the COMCUBE-S CubeSat Swarm—Design and Performance Simulations

by Nathan Franel, Vincent Tatischeff, David Murphy, Alexey Ulyanov, Caimin McKenna, Lorraine Hanlon, Prerna Baranwal, Christophe Beigbeder, Arnaud Claret, Ion Cojocari, Nicolas de Séréville, Nicolas Dosme, Eric Doumayrou, Mariya Georgieva, Clarisse Hamadache, Sally Hankache, Jimmy Jeglot, Mózsi Kiss, Beng-Yun Ky, Vincent Lafage, Philippe Laurent, Christine Le Galliard, Joseph Mangan, Aline Meuris, Mark Pearce, Jean Peyré, Arjun Poitaya, Diana Renaud, Arnaud Saussac, Varun Varun, Matias Vecchio and Colin Wade Show full author list Hide full author list

Particles 2026, 9(1), 13; https://doi.org/10.3390/particles9010013 - 6 Feb 2026

Cited by 1 | Viewed by 958

Abstract

COMCUBE-S (Compton Telescope CubeSat Swarm) is a proposed mission aimed at understanding the radiation mechanisms of ultra-relativistic jets from Gamma-Ray Bursts (GRBs). It consists of a swarm of 16U CubeSats carrying a state-of-the-art Compton polarimeter and a bismuth germanium oxide (BGO) spectrometer to [...] Read more.

COMCUBE-S (Compton Telescope CubeSat Swarm) is a proposed mission aimed at understanding the radiation mechanisms of ultra-relativistic jets from Gamma-Ray Bursts (GRBs). It consists of a swarm of 16U CubeSats carrying a state-of-the-art Compton polarimeter and a bismuth germanium oxide (BGO) spectrometer to perform timing, spectroscopic and polarimetric measurements of the prompt emission from GRBs. The mission is currently in a feasibility study phase (Phase A) with the European Space Agency to prepare an in-orbit demonstration. Here, we present the simulation work used to optimise the design and operational concept of the microsatellite constellation, as well as estimate the mission performance in terms of GRB detection rate and polarimetry. We used the MEGAlib software to simulate the response function of the gamma-ray instruments, together with a detailed model for the background particle and radiation fluxes in low-Earth orbit. We also developed a synthetic GRB population model to best estimate the detection rate. These simulations show that COMCUBE-S will detect about 2 GRBs per day, which is significantly higher than that of all past and current GRB missions. Furthermore, simulated performance for linear polarisation measurements shows that COMCUBE-S will be able to uniquely distinguish between competing models of the GRB prompt emission, thereby shedding new light on some of the most fundamental aspects of GRB physics. 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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14 pages, 543 KB

Open AccessArticle

Clusters of PBHs in a Framework of Multidimensional f(R)-Gravity

by Maxim Krasnov and Valery Nikulin

Particles 2026, 9(1), 12; https://doi.org/10.3390/particles9010012 - 3 Feb 2026

Viewed by 883

Abstract

We investigate primordial black hole (PBH) production via the collapse of supercritical domain walls in a quadratic

f (R)

-gravity model with tensor extensions. The effective field theory for an extra space’s scalar curvature provides a foundation for the formation of [...] Read more.

We investigate primordial black hole (PBH) production via the collapse of supercritical domain walls in a quadratic

f (R)

-gravity model with tensor extensions. The effective field theory for an extra space’s scalar curvature provides a foundation for the formation of these dense walls. In our work, domain walls are found to be supercritical. Their properties were extensively studied in the literature, where it was demonstrated that they create wormholes and escape into baby universes through them. Closure of the wormhole leads to black hole creation, providing a mechanism for the production of primordial black holes in our model. We calculate the mass spectrum of such black holes and mass distribution within clusters of them. When accretion is accounted for, the black holes produced under this mechanism present viable dark matter candidates. Full article

(This article belongs to the Special Issue Selected Papers from XXVIII Workshop “What Comes Beyond the Standard Models?”: New Trends in Particle Cosmology)

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28 pages, 438 KB

Open AccessArticle

H

olographic

N

aturalness and Information See-Saw Mechanism for Neutrinos

by Andrea Addazi and Giuseppe Meluccio

Particles 2026, 9(1), 11; https://doi.org/10.3390/particles9010011 - 2 Feb 2026

Viewed by 933

Abstract

The microscopic origin of the de Sitter entropy remains a central puzzle in quantum gravity that is related to the cosmological constant problem. Within the paradigm of

H

olographic

N

aturalness, we propose that this entropy is carried by a vast number of [...] Read more.

The microscopic origin of the de Sitter entropy remains a central puzzle in quantum gravity that is related to the cosmological constant problem. Within the paradigm of

H

olographic

N

aturalness, we propose that this entropy is carried by a vast number of light, coherent degrees of freedom—called “hairons”—which emerge as the moduli of gravitational instantons on orbifolds. Starting from the Euclidean de Sitter instanton (

S^{4}

), we construct a new class of orbifold gravitational instantons,

S^{4} / Z_{N}

, where N corresponds to the de Sitter entropy. We demonstrate that the dimension of the moduli space of these instantons scales linearly with N, and we identify these moduli with the hairon fields. A

Z_{N}

symmetry, derived from Wilson loops in the instanton background, ensures the distinguishability of these modes, leading to the correct entropy count. The hairons acquire a mass of the order of the Hubble scale and exhibit negligible mutual interactions, suggesting that the de Sitter vacuum is a coherent state, or Bose–Einstein condensate, of these fundamental excitations. Then, we present a novel framework which unifies neutrino mass generation with the cosmological constant through gravitational topology and holography. The small neutrino mass scale emerges naturally from first principles, without requiring new physics beyond the Standard Model and Gravity. The gravitational Chern–Simons structure and its anomaly with neutrinos force a topological Higgs mechanism, leading to neutrino condensation via

S^{4} / Z_{N}

gravitational instantons. The number of topological degrees of freedom

N \sim M_{P}^{2} / Λ \sim 10^{120}

provides both the holographic counting of the de Sitter entropy and a

1 / N

information see-saw mechanism for neutrino masses. Our framework makes the following predictions: (i) a neutrino superfluid condensation forming Cooper pairs below meV energies, as a viable candidate for cold dark matter; (ii) a possible resolution of the strong CP problem through a QCD composite axion state; (iii) time-varying neutrino masses which track the evolution of dark energy; and (iv) several distinctive signatures in astroparticle physics, ultra-high-energy cosmic rays and high magnetic field experiments. Full article

(This article belongs to the Special Issue Selected Papers from XXVIII Workshop “What Comes Beyond the Standard Models?”: New Trends in Particle Cosmology)

8 pages, 1153 KB

Open AccessArticle

Evaluation of a Timepix3 Telescope for Applications as a Compton Scatter Polarimeter for Hard X- and Soft γ-Rays

by Jindrich Jelinek, Benedikt Bergmann and Petr Smolyanskiy

Particles 2026, 9(1), 10; https://doi.org/10.3390/particles9010010 - 2 Feb 2026

Viewed by 742

Abstract

This work presents a simulation study of a Timepix3 telescope composed of nine detectors for use as a Compton scatter polarimeter in the energy range of 35–100 keV. Four detectors carry 1 mm thick silicon (Si) sensors and five detectors carry 1 mm [...] Read more.

This work presents a simulation study of a Timepix3 telescope composed of nine detectors for use as a Compton scatter polarimeter in the energy range of 35–100 keV. Four detectors carry 1 mm thick silicon (Si) sensors and five detectors carry 1 mm thick cadmium telluride (CdTe) sensors. The modulation factor for 100% linearly polarized X-ray beams was found to be

μ_{100} > 70 %

in the energy range of 55–80 keV. The quality factor of the polarimeter has its maximum 12.8% at the energy 75 keV. The comparison of quality factors and the calculations of a hypothetical observation of the Crab nebula show that this multilayer Timepix3 approach is competitive with contemporary X-ray polarimeters. 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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14 pages, 4073 KB

Open AccessConference Report

High-Precision Cross-Sections for Galactic Cosmic Rays: Highlights from XSCRC2024 and Follow-Up Actions

by David Maurin, Fiorenza Donato and Saverio Mariani

Particles 2026, 9(1), 9; https://doi.org/10.3390/particles9010009 - 26 Jan 2026

Viewed by 644

Abstract

The interpretation of high-precision Galactic cosmic-ray data from AMS-02, CALET, DAMPE, etc., is fundamentally limited by nuclear cross-sections uncertainties. This proceeding highlights the results presented at the XSCRC2024 workshop, which aims at bringing together the cosmic-ray, nuclear, and particle physics communities, with the [...] Read more.

The interpretation of high-precision Galactic cosmic-ray data from AMS-02, CALET, DAMPE, etc., is fundamentally limited by nuclear cross-sections uncertainties. This proceeding highlights the results presented at the XSCRC2024 workshop, which aims at bringing together the cosmic-ray, nuclear, and particle physics communities, with the goal of improving cross-section measurements across various domains, from nuclei production for constraining cosmic-ray transport parameters, to antiproton and anti-deuteron production for dark matter searches. This workshop lead to a comprehensive roadmap for new cross-section measurements in the next decade, as well as other outcomes. 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, 685 KB

Open AccessArticle

Identified-Hadron Spectra in π⁺ + Be at 60 GeV/c with Channel-Wise Subcollision Acceptance in PYTHIA 8 Angantyr

by Nuha Felemban

Particles 2026, 9(1), 8; https://doi.org/10.3390/particles9010008 - 19 Jan 2026

Viewed by 478

Abstract

Identified-hadron production (p,

π^{\pm}

,

K^{\pm}

) in

π^{+} + Be

at

p_{lab} = 60 GeV / c

(

\sqrt{s} ≃ 10.6 GeV

) is investigated using Pythia 8.315 (Monash tune) with the Angantyr extension. Differential multiplicities [...] Read more.

Identified-hadron production (p,

π^{\pm}

,

K^{\pm}

) in

π^{+} + Be

at

p_{lab} = 60 GeV / c

(

\sqrt{s} ≃ 10.6 GeV

) is investigated using Pythia 8.315 (Monash tune) with the Angantyr extension. Differential multiplicities

d^{2} n / (d p d θ)

are confronted with NA61/SHINE measurements across standard

θ

bins. Within the fluctuating-radii Double-Strikman (DS) scheme, two unsuppressed opacity mappings are compared to quantify systematics. In addition, a minimal extension is introduced: a flat, post-classification, channel-wise acceptance applied after ND/SD/DD/EL tagging. It acts on primary and secondary

π N

pairs, keeps hadronization fixed (Lund string), and leaves the internal event generation of each admitted subcollision unchanged. Opacity-mapping variations alone induce only percent-level differences and do not resolve the soft/forward tensions. By contrast, the flat acceptance—interpretable as a reduced effective ND weight—improves agreement across species and angles. It hardens the forward

π^{+}

spectra and lowers large-

θ

yields, produces milder charge-asymmetric changes for

π^{-}

consistent with the weaker leading feed, suppresses proton yields at all angles (with a residual

\sim 30 %

forward high-p deficit), and improves

K^{\pm}

, with a stronger effect for

K^{+}

than

K^{-}

. These results show that a geometry-blind reweighting of the subcollision mixture suffices to capture the main NA61/SHINE trends for

π^{+} + Be

at SPS energies without modifying hadronization. The approach provides a controlled baseline for subsequent, channel-balanced refinements and broader

π^{+} A

tuning. Full article

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

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11 pages, 4363 KB

Open AccessArticle

Testing and Characterization of Detection Plane Elements of the XGIS Instrument on Board the THESEUS Mission

by Smiriti Srivastava, Evgeny Demenev, Claudio Labanti, Lorenzo Amati, Riccardo Campana, Giuseppe Baldazzi, Edoardo Borciani, Paolo Calabretto, Francesco Ficorella, Ezequiel J. Marchesini, Giulia Mattioli, Ajay Sharma, David Novel, Giancarlo Pepponi and Enrico Virgilli

Particles 2026, 9(1), 7; https://doi.org/10.3390/particles9010007 - 18 Jan 2026

Viewed by 702

Abstract

This paper presents the procedures employed for experimental functional and performance characterization of a 2 × 2 pixel prototype detection system tailored specifically for the X and Gamma-ray Imaging Spectrometer (XGIS) instrument onboard the THESEUS mission. The XGIS system comprises of two coded [...] Read more.

This paper presents the procedures employed for experimental functional and performance characterization of a 2 × 2 pixel prototype detection system tailored specifically for the X and Gamma-ray Imaging Spectrometer (XGIS) instrument onboard the THESEUS mission. The XGIS system comprises of two coded masked wide field cameras integrated with monolithic SDDs (Silicon Drift Detectors) and CsI:Tl (Thallium doped-Cesium Iodide) scintillators, contributing to its broad X and

γ

-ray detection range. Given the space instrumentation complexity, thorough requirement qualification and testing procedures are essential. This work focuses on working principle, the testing setup utilized, and observed performance for the small scale four-pixel XGIS prototype. Furthermore, the alignment of light output performance of the four-pixel SDD and scintillator prototype detection system with the XGIS instrument requirements is emphasized. 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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22 pages, 26643 KB

Open AccessArticle

Critical Aspects in the Modeling of Sub-GeV Calorimetric Particle Detectors: The Case Study of the High-Energy Particle Detector (HEPD-02) on Board the CSES-02 Satellite

by Simona Bartocci, Roberto Battiston, Stefania Beolè, Franco Benotto, Piero Cipollone, Silvia Coli, Andrea Contin, Marco Cristoforetti, Cinzia De Donato, Cristian De Santis, Andrea Di Luca, Floarea Dumitrache, Francesco Maria Follega, Simone Garrafa Botta, Giuseppe Gebbia, Roberto Iuppa, Alessandro Lega, Mauro Lolli, Giuseppe Masciantonio, Matteo Mergè, Marco Mese, Riccardo Nicolaidis, Francesco Nozzoli, Alberto Oliva, Giuseppe Osteria, Francesco Palma, Federico Palmonari, Beatrice Panico, Stefania Perciballi, Francesco Perfetto, Piergiorgio Picozza, Michele Pozzato, Marco Ricci, Ester Ricci, Sergio Bruno Ricciarini, Zouleikha Sahnoun, Umberto Savino, Valentina Scotti, Enrico Serra, Alessandro Sotgiu, Roberta Sparvoli, Pietro Ubertini, Veronica Vilona, Simona Zoffoli and Paolo Zuccon Show full author list Hide full author list

Particles 2026, 9(1), 6; https://doi.org/10.3390/particles9010006 - 15 Jan 2026

Cited by 1 | Viewed by 1143

Abstract

The accurate simulation of sub-GeV particle detectors is essential for interpreting experimental data and optimizing detector design. This work identifies and addresses several critical aspects in modeling such detectors, taking as a case study the High-Energy Particle Detector (HEPD-02), a space-borne instrument developed [...] Read more.

The accurate simulation of sub-GeV particle detectors is essential for interpreting experimental data and optimizing detector design. This work identifies and addresses several critical aspects in modeling such detectors, taking as a case study the High-Energy Particle Detector (HEPD-02), a space-borne instrument developed within the CSES-02 mission to measure electrons in the ∼3–100 MeV range, protons and light nuclei in the ∼30–200 MeV/n. The HEPD-02 instrument consists of a silicon tracker, plastic and LYSO scintillator calorimeters, and anticoincidence systems, making it a representative example of a complex low-energy particle detector operating in Low Earth Orbit. Key challenges arise from replicating intricate detector geometries derived from CAD models, selecting appropriate hadronic physics lists for low-energy interactions, and accurately describing the detector response—particularly quenching effects in scintillators and digitization in solid-state tracking planes. Particular attention is given to three critical aspects: the precise CAD-level geometry implementation, the impact of hadronic physics models on the detector response, and the parameterization of scintillation quenching. In this study, we present original solutions to these challenges and provide data–MC comparisons using data from HEPD-02 beam tests. Full article

(This article belongs to the Section Experimental Physics and Instrumentation)

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14 pages, 423 KB

Open AccessArticle

Coherent State Description of Astrophysical Gamma-Ray Amplification from a Para-Positronium Condensate

by Diego Julio Cirilo-Lombardo

Particles 2026, 9(1), 5; https://doi.org/10.3390/particles9010005 - 14 Jan 2026

Viewed by 475

Abstract

The para-positronium system

({}^{1}S_{0} P s)

is described by means of specially constructed coherent states (CSs) in the Klauder–Perelomov sense. It is analyzed from the physical point of view and from the geometry underlying the relevant symmetry group establishing the dynamics [...] Read more.

The para-positronium system

({}^{1}S_{0} P s)

is described by means of specially constructed coherent states (CSs) in the Klauder–Perelomov sense. It is analyzed from the physical point of view and from the geometry underlying the relevant symmetry group establishing the dynamics of the processes. In this new theoretical context, the possibility of a gamma-ray laser emission is investigated within a QFT context, showing explicitly that, in addition to the oscillator solution based only on a Bogoliubov approximation for the condensate, there is a second phase or “squeezed” stage by which physical features beyond the classical ones appear. Explicitly, while the generated photons are in the active medium (e.g., Ps-BEC), the evolution is described by a Heisenberg–Weyl coherent state with displacement operators dependent on the interaction time, which is related to the condensate shape. After the interaction time has elapsed, we explicitly demonstrate that the displacement operator of the

{}^{1}S_{0} P s

is transformed into a squeezed operator of the photonic fields modulated by the matrix element of the Positronium decay

M_{{}^{1}S_{0} P s} \to 2 γ

. We also show that this squeezed operator (belonging to the Metaplectic group) generates a non-classical radiation state spanning only even (s = 1/4) levels in the number of photons. The implications in astrophysical systems of interest, considering gamma-ray coherent emission and the possibility of an

{}^{1}S_{0} P s - B E C

in the context of pulsars, blazars, and quasars, are briefly discussed. Full article

(This article belongs to the Section Astroparticle Physics and Cosmology)

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17 pages, 3794 KB

Open AccessArticle

Spectral Performance of Single-Channel Plastic and GAGG Scintillator Bars of the CUbesat Solar Polarimeter (CUSP)

by Nicolas De Angelis, Abhay Kumar, Sergio Fabiani, Ettore Del Monte, Enrico Costa, Giovanni Lombardi, Alda Rubini, Paolo Soffitta, Andrea Alimenti, Riccardo Campana, Mauro Centrone, Giovanni De Cesare, Sergio Di Cosimo, Giuseppe Di Persio, Alessandro Lacerenza, Pasqualino Loffredo, Gabriele Minervini, Fabio Muleri, Paolo Romano, Emanuele Scalise, Enrico Silva, Davide Albanesi, Ilaria Baffo, Daniele Brienza, Valerio Campomaggiore, Giovanni Cucinella, Andrea Curatolo, Giulia de Iulis, Andrea Del Re, Vito Di Bari, Simone Di Filippo, Immacolata Donnarumma, Pierluigi Fanelli, Nicolas Gagliardi, Paolo Leonetti, Matteo Mergè, Dario Modenini, Andrea Negri, Daniele Pecorella, Massimo Perelli, Alice Ponti, Francesca Sbop, Paolo Tortora, Alessandro Turchi, Valerio Vagelli, Emanuele Zaccagnino, Alessandro Zambardi and Costantino Zazza Show full author list Hide full author list

Particles 2026, 9(1), 4; https://doi.org/10.3390/particles9010004 - 13 Jan 2026

Viewed by 699

Abstract

Our Sun is the closest X-ray astrophysical source to Earth. As such, it makes for a strong case study to better understand astrophysical processes. Solar flares are particularly interesting as they are linked to coronal mass ejections as well as magnetic field reconnection [...] Read more.

Our Sun is the closest X-ray astrophysical source to Earth. As such, it makes for a strong case study to better understand astrophysical processes. Solar flares are particularly interesting as they are linked to coronal mass ejections as well as magnetic field reconnection sites in the solar atmosphere. Flares can therefore provide insightful information on the physical processes at play on their production sites but also on the emission and acceleration of energetic charged particles towards our planet, making it an excellent forecasting tool for space weather. While solar flares are critical to understanding magnetic reconnection and particle acceleration, their hard X-ray polarization—key to distinguishing between competing theoretical models—remains poorly constrained by existing observations. To address this, we present the CUbesat Solar Polarimeter (CUSP), a mission under development to perform solar flare polarimetry in the 25–100 keV energy range. CUSP consists of a 6U-XL platform hosting a dual-phase Compton polarimeter. The polarimeter is made of a central assembly of four 4 × 4 arrays of plastic scintillators, each coupled to multi-anode photomultiplier tubes, surrounded by four strips of eight elongated GAGG scintillator bars coupled to avalanche photodiodes. Both types of sensors from Hamamatsu are, respectively, read out by the MAROC-3A and SKIROC-2A ASICs from Weeroc. In this manuscript, we present the preliminary spectral performances of single plastic and GAGG channels measured in a laboratory using development boards of the ASICs foreseen for the flight model. 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, 5795 KB

Open AccessTechnical Note

The X and Gamma-Ray Imager and Spectrometer Onboard THESEUS—Status and Technological Progresses

by Giulia Mattioli, Claudio Labanti, Enrico Virgilli, Lorenzo Amati, Riccardo Campana, Giuseppe Baldazzi, Smiriti Srivastava, Edoardo Borciani, Paolo Calabretto, Ezequiel J. Marchesini, Ajay Sharma, Evgeny Demenev, Francesco Ficorella, David Novel, Giancarlo Pepponi, Giovanni La Rosa, Paolo Nogara and Giuseppe Sottile

Particles 2026, 9(1), 3; https://doi.org/10.3390/particles9010003 - 8 Jan 2026

Cited by 1 | Viewed by 893

Abstract

Gamma-Ray Bursts (GRBs) are intense bursts of high-energy photons which, in just a few seconds, outshine all other

γ

-ray emitters in the sky. Due to their extreme luminosity, GRBs are not only important as high-energy astrophysical phenomena but also serve as valuable [...] Read more.

Gamma-Ray Bursts (GRBs) are intense bursts of high-energy photons which, in just a few seconds, outshine all other

γ

-ray emitters in the sky. Due to their extreme luminosity, GRBs are not only important as high-energy astrophysical phenomena but also serve as valuable probe models of the far, high-redshift Universe. The importance of these events has pushed the High-Energy Astrophysics community to propose new mission concepts over the past decade, prompting dedicated research and development efforts to achieve the required technological readiness levels. The X and Gamma-Ray Imager and Spectrometer (XGIS) is one of the two GRB monitors onboard the proposed, upcoming THESEUS space mission. Building on strong heritage from previous studies, ongoing developments and optimizations are focused on enhancing the instrument’s capabilities and increasing its technological maturity. This work presents the current status of the XGIS instrument and the latest technological advancements achieved in preparation for its deployment on THESEUS. 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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17 pages, 9090 KB

Open AccessArticle

Unlocking the Future of X-Ray Polarimetry with IXPE: Lessons Learned and Next Steps

by Paolo Soffitta, Enrico Costa, Ettore Del Monte, Alessandro Di Marco, Sergio Fabiani, Riccardo Ferrazzoli, Fabio La Monaca, Fabio Muleri, Alda Rubini and Alessio Trois

Particles 2026, 9(1), 2; https://doi.org/10.3390/particles9010002 - 6 Jan 2026

Cited by 1 | Viewed by 964

Abstract

This paper discusses issues encountered during the early development of the instrument on the Imaging X-ray Polarimetry Explorer (IXPE), a NASA–ASI Small Explorer mission launched on 9 December 2021. IXPE has observed about 100 sources, yielding meaningful polarimetry for most of them. An [...] Read more.

This paper discusses issues encountered during the early development of the instrument on the Imaging X-ray Polarimetry Explorer (IXPE), a NASA–ASI Small Explorer mission launched on 9 December 2021. IXPE has observed about 100 sources, yielding meaningful polarimetry for most of them. An on-board calibration system mitigated most non-ideal detector behaviors during operations. Data from the on-board polarized and unpolarized X-ray sources are routinely ingested by the flight pipeline to correct the instrument response in a manner transparent to users. Based on its scientific return and payload health, the IXPE mission has been extended through 2028. The lessons learned are informing the design of next-generation X-ray polarimetry missions, as discussed elsewhere in these conferences. 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, 2599 KB

Open AccessReview

Review of the Performance of the CMS Hadron Calorimeter

by Yide Wei and Hui Wang

Particles 2026, 9(1), 1; https://doi.org/10.3390/particles9010001 - 2 Jan 2026

Viewed by 970

Abstract

The hadron calorimeter is a central component of the CMS detector, vital for measuring hadron energies and reconstructing missing transverse momentum. This paper reviews its performance before and after the Phase 1 upgrade (completed in 2019), which upgraded both back-end and front-end electronics, [...] Read more.

The hadron calorimeter is a central component of the CMS detector, vital for measuring hadron energies and reconstructing missing transverse momentum. This paper reviews its performance before and after the Phase 1 upgrade (completed in 2019), which upgraded both back-end and front-end electronics, including photodetectors and charge-integrating ADC with precise-timing TDC, as well as its depth segmentation in the barrel and endcaps. This paper describes energy reconstruction algorithms that suppress out-of-time signals, along with high-precision timing alignment and multi-step energy calibration procedures to mitigate radiation damage and improve energy resolution Performance evaluations using proton–proton collision data demonstrate that the upgraded detector and reconstruction techniques achieve good resolution and robust operation under high-luminosity conditions. 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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