Particles

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

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 156

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 175

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 159

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 134

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 133

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 187

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

Viewed by 193

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 126

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 237

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

Viewed by 251

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

Viewed by 289

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 279

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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