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9 pages, 340 KiB

Open AccessArticle

A Systematic Approach to Studying Quark Energy Loss in Nuclei Using Positive Pions

by Nicolás Zambra-Gómez, William K. Brooks and Nicolás Viaux

Particles 2025, 8(2), 44; https://doi.org/10.3390/particles8020044 - 15 Apr 2025

Viewed by 139

Abstract

Our objective is to test the published models of partonic energy loss, particularly those describing the energy loss mechanisms of quarks traversing nuclear matter, within the framework of semi-inclusive deep inelastic scattering. Our methodological approach focuses on quantifying the quark energy loss in [...] Read more.

Our objective is to test the published models of partonic energy loss, particularly those describing the energy loss mechanisms of quarks traversing nuclear matter, within the framework of semi-inclusive deep inelastic scattering. Our methodological approach focuses on quantifying the quark energy loss in cold matter by analyzing the positive pions (

π^{+}

) produced in various nuclear targets, including deuterium, carbon, iron and lead, while our first approach only includes deuterium and carbon. Before normalizing the pions’ energy distribution to unity to perform a shape analysis, acceptance corrections were performed to account for the detector’s efficiency and ensure accurate comparisons of the spectra. By normalizing the energy spectra of

π^{+}

produced from these distinct targets and based on the Baier–Dokshitzer–Mueller–Peigné–Schiff theory, which posits that quark energy loss depends only on nuclear size, it is assumed that the energy distributions of the targets will exhibit similar behavior. For this normalization, an energy shift between these distributions, corresponding to the quark energy loss, is identified. To ensure accuracy, statistical techniques such as the Kolmogorov–Smirnov test are used. The data used to test and explore the analysis technique and method were from the CLAS6 EG2 dataset collected using Jefferson Lab’s CLAS detector. Full article

(This article belongs to the Special Issue Selected Papers from the 13th International Conference on New Frontiers in Physics (ICNFP 2024))

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6 pages, 1393 KiB

Open AccessArticle

Results from Cryo-PoF Project: Power over Fiber at Cryogenic Temperature for Fundamental and Applied Physics

by Andrea Falcone, Alessandro Andreani, Claudia Brizzolari, Esteban Javier Cristaldo Morales, Maritza Juliette Delgado Gonzales, Claudio Gotti, Massimo Lazzaroni, Luca Meazza, Gianluigi Pessina, Francesco Terranova, Marta Torti and Valeria Trabattoni

Particles 2025, 8(2), 41; https://doi.org/10.3390/particles8020041 - 8 Apr 2025

Viewed by 147

Abstract

The Cryo-PoF project is an R&D project funded by the Italian Insitute for Nuclear Research (INFN) in Milano-Bicocca (Italy). The technology at the basis of the project is Power over Fiber (PoF). By sending laser light through an optical fiber, this technology delivers [...] Read more.

The Cryo-PoF project is an R&D project funded by the Italian Insitute for Nuclear Research (INFN) in Milano-Bicocca (Italy). The technology at the basis of the project is Power over Fiber (PoF). By sending laser light through an optical fiber, this technology delivers electrical power to a photovoltaic power converter, in order to power sensors or electrical devices. Among the several advantages this solution can provide, we can underline the spark-free operation when electric fields are present, the removal of noise induced by power lines, the absence of interference with electromagnetic fields, and robustness in hostile environments. R&D for the application of PoF in cryogenic environments started at Fermilab in 2020; for the DUNE Vertical Drift detector, it was needed to operate the Photon Detector System on a high-voltage cathode surface. Cryo-PoF, starting from this project, developed a single-laser input line system to power, at cryogenic temperatures, both an electronic amplifier and Photon Detection devices, tuning their bias by means of the input laser power, without adding ancillary fibers. The results obtained in Milano-Bicocca will be discussed, presenting the tests performed using power photosensors at liquid nitrogen temperature. Full article

(This article belongs to the Special Issue Selected Papers from the 13th International Conference on New Frontiers in Physics (ICNFP 2024))

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13 pages, 6249 KiB

Open AccessArticle

The High-Granularity Timing Detector for ATLAS at HL-LHC

by Joaquim Pinol

Particles 2025, 8(2), 36; https://doi.org/10.3390/particles8020036 - 1 Apr 2025

Viewed by 143

Abstract

The increased particle flux expected at the HL-LHC poses a serious challenge for the ATLAS detector performance, especially in the forward region. The High-Granularity Timing Detector (HGTD), featuring novel Low-Gain Avalanche Detector silicon technology, will provide pile-up mitigation and luminosity measurement capabilities, and [...] Read more.

The increased particle flux expected at the HL-LHC poses a serious challenge for the ATLAS detector performance, especially in the forward region. The High-Granularity Timing Detector (HGTD), featuring novel Low-Gain Avalanche Detector silicon technology, will provide pile-up mitigation and luminosity measurement capabilities, and augment the new all-silicon Inner Tracker in the pseudo-rapidity range from 2.4 to 4.0. Two double-sided layers will provide a timing resolution better than 50 ps/track for MIPs throughout the HL-LHC running period, and provide a new timing-based handle to assign particles to the correct vertex. The LGAD technology provides suitable gain to reach the required signal-to-noise ratio, and a granularity of 1.3 × 1.3 mm² (with 3.6 M channels in total). This paper presents the current status of the HGTD project with emphasis on the sensor development and module results. Full article

(This article belongs to the Special Issue Selected Papers from the 13th International Conference on New Frontiers in Physics (ICNFP 2024))

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11 pages, 323 KiB

Open AccessArticle

HYDrodynamics with JETs (HYDJET++): Latest Developments and Results

by Garnik Ambaryan, Larissa Bravina, Alexey Chernyshov, Gyulnara Eyyubova, Vladimir Korotkikh, Igor Lokhtin, Sergei Petrushanko, Alexandr Snigirev and Evgeny Zabrodin

Particles 2025, 8(2), 35; https://doi.org/10.3390/particles8020035 - 1 Apr 2025

Viewed by 118

Abstract

Analysis of the (i) charge balance function and (ii) fluctuations of the net electric charge of hadrons in

P b

+

P b

collisions at center-of-mass energy 2.76 TeV per nucleon pair was performed within a two-component hydjet++ model. It is shown that [...] Read more.

Analysis of the (i) charge balance function and (ii) fluctuations of the net electric charge of hadrons in

P b

+

P b

collisions at center-of-mass energy 2.76 TeV per nucleon pair was performed within a two-component hydjet++ model. It is shown that neither the widths of the balance function nor the strongly intensive quantities, D and Σ, used to describe the net-charge fluctuations, can be reproduced within the model based on a grand canonical ensemble approach for generating multiparticle production. To solve this problem, it is necessary to take into account exact charge conservation in an event-by-event basis. The corresponding procedure was developed and implemented in the modified hydjet++ model. It provides a fair description of the experimental data. Full article

(This article belongs to the Special Issue Selected Papers from the 13th International Conference on New Frontiers in Physics (ICNFP 2024))

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14 pages, 732 KiB

Open AccessArticle

A System Size Analysis of the Fireball Produced in Heavy-Ion Collisions

by Egor Nedorezov, Alexey Aparin, Alexandru Parvan and Vinh Ba Luong

Particles 2025, 8(1), 34; https://doi.org/10.3390/particles8010034 - 19 Mar 2025

Viewed by 177

Abstract

One of the main interests of high-energy physics is the study of the phase diagram and the localization of phase transitions from hadronic to quark–gluonic matter. There are different techniques to study the hot matter. One of them is femtoscopy, which uses two-particle [...] Read more.

One of the main interests of high-energy physics is the study of the phase diagram and the localization of phase transitions from hadronic to quark–gluonic matter. There are different techniques to study the hot matter. One of them is femtoscopy, which uses two-particle correlations to extract spatiotemporal characteristics of the emission source. Another approach involves obtaining thermodynamic parameters from the momentum distributions of produced particles based on various theoretical models. In this research, we perform a comparative analysis of femtoscopic volumes and volumes obtained using the Tsallis statistical fit. This analysis allows us to estimate system size at the time of kinetic freeze-out and its dependence on collision centrality and energy. We observe that at high energies, the volume values estimated taking the two approaches diverge significantly, while at low energies, they are more consistent. In the future, these results can help to combine these two different methods and provide a more comprehensive picture of the fireball produced in heavy-ion collisions. Full article

(This article belongs to the Special Issue Selected Papers from the 13th International Conference on New Frontiers in Physics (ICNFP 2024))

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6 pages, 1598 KiB

Open AccessArticle

Non-Resonant Di-Higgs Searches at the Large Hadron Collider with the CMS Experiment

by Simona Palluotto

Particles 2025, 8(1), 31; https://doi.org/10.3390/particles8010031 - 6 Mar 2025

Viewed by 377

Abstract

Investigating the production of Higgs boson pairs (HH) at the LHC provides critical insights into the self-interaction properties of the Higgs boson, representing an essential verification of the Standard Model and contributing to our understanding of the Higgs boson properties. This work highlights [...] Read more.

Investigating the production of Higgs boson pairs (HH) at the LHC provides critical insights into the self-interaction properties of the Higgs boson, representing an essential verification of the Standard Model and contributing to our understanding of the Higgs boson properties. This work highlights the latest findings from the CMS collaboration on HH production measurements. These searches include different final states and integrate data collected by the CMS experiment at a center-of-mass energy of 13 TeV. Full article

(This article belongs to the Special Issue Selected Papers from the 13th International Conference on New Frontiers in Physics (ICNFP 2024))

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10 pages, 846 KiB

Open AccessArticle

Higgs Physics at the Muon Collider

by Luca Castelli

Particles 2025, 8(1), 28; https://doi.org/10.3390/particles8010028 - 5 Mar 2025

Viewed by 446

Abstract

A multi-TeV muon collider produces a significant amount of Higgs bosons allowing for precise measurements of its couplings to Standard Model fundamental particles. Moreover, Higgs boson pairs are produced with a relevant cross-section, allowing for the determination of the second term of the [...] Read more.

A multi-TeV muon collider produces a significant amount of Higgs bosons allowing for precise measurements of its couplings to Standard Model fundamental particles. Moreover, Higgs boson pairs are produced with a relevant cross-section, allowing for the determination of the second term of the Higgs potential by measuring the double Higgs production cross-section and therefore the trilinear self-coupling term. This contribution aims to give an overview of the Higgs measurement accuracies expected for the initial stage of the muon collider at

\sqrt{s} = 3 TeV

with an integrated luminosity of

1 a b^{- 1}

and for the target center-of-mass energy at

10 TeV

with

10 a b^{- 1}

integrated luminosity. The results are obtained using the full detector simulations which include both physical and machine backgrounds. Full article

(This article belongs to the Special Issue Selected Papers from the 13th International Conference on New Frontiers in Physics (ICNFP 2024))

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11 pages, 4733 KiB

Open AccessArticle

Ionization Dynamics in Matter with Gold Nanoparticles upon Laser Irradiation of Various Intensities, Numerical Analysis

by Konstantin Zsukovszki and Istvan Papp

Particles 2025, 8(1), 27; https://doi.org/10.3390/particles8010027 - 4 Mar 2025

Viewed by 511

Abstract

We perform the numerical study of the response of the media with golden nanoantennas upon irradiation by intense ~10¹⁷–10¹⁸ W/cm² short 0.1 ps laser pulses. We study the influence of resonant nanoantennas on the ionization process and on the [...] Read more.

We perform the numerical study of the response of the media with golden nanoantennas upon irradiation by intense ~10¹⁷–10¹⁸ W/cm² short 0.1 ps laser pulses. We study the influence of resonant nanoantennas on the ionization process and on the ions’ energy evolution at various intensities of laser pulses. Numerical modeling is performed with the help of EPOCH software using the “particle-in-cell” numeral method. The response of resonating nanoantennas of dipole and crossed shapes, embedded in dense media, is studied. The dynamics of ionization and the energies of ions acquired during the passage of the laser pulse are studied. The differences in the ionization energies for nanoantennas of dipole and crossed shapes are explored. The ionization dynamics in the matter doped with nanoantennas is examined; crossed-shaped antennas are identified for the best energy absorption in high-intensity fields. Full article

(This article belongs to the Special Issue Selected Papers from the 13th International Conference on New Frontiers in Physics (ICNFP 2024))

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11 pages, 1671 KiB

Open AccessArticle

Photoproduction of Heavy Meson and Photon Pairs

by Marat Siddikov

Particles 2025, 8(1), 23; https://doi.org/10.3390/particles8010023 - 3 Mar 2025

Viewed by 425

Abstract

The extraction of the Generalized Parton Distributions of the nucleons from phenomenological analyses of experimental data presents a challenging problem which is being actively studied in the literature. Due to theoretical limitations of some of the well-known channels, currently many new processes are [...] Read more.

The extraction of the Generalized Parton Distributions of the nucleons from phenomenological analyses of experimental data presents a challenging problem which is being actively studied in the literature. Due to theoretical limitations of some of the well-known channels, currently many new processes are being analyzed in the literature as potential novel probes. In this proceeding we propose to use the exclusive photoproduction of

η_{c} γ

pairs as a new channel for study of the GPDs. Our analysis shows that this process is primarily sensitive to the unpolarized gluon GPDs

H_{g}

in the Efremov-Radyushkin-Brodsky-Lepage (ERBL) kinematics. The numerical estimates of the cross-section and the expected counting rates for middle-energy photoproduction experiments show that expected counting rates are sufficiently large for a dedicated experimental study at the future Electron-Ion Collider (EIC) or in ultraperipheral collisions at the LHC. The total (integrated) photoproduction cross-section

σ_{tot}^{γ p \to γ η_{c} p}

in this kinematics scales with energy W as

σ_{tot}^{γ p \to γ η_{c} p} (W, M_{γ η_{c}} \geq 3.5 GeV) \approx 0.48 pb {(\frac{W}{100 GeV})}^{0.75},

and yields a few thousands of events per

100 {fb}^{- 1}

of the integrated luminosity. Full article

(This article belongs to the Special Issue Selected Papers from the 13th International Conference on New Frontiers in Physics (ICNFP 2024))

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8 pages, 8051 KiB

Open AccessArticle

Performance of the ICARUS Trigger System at the Booster and NuMI Neutrino Beams

by Riccardo Triozzi

Particles 2025, 8(1), 22; https://doi.org/10.3390/particles8010022 - 3 Mar 2025

Viewed by 410

Abstract

The ICARUS-T600 liquid argon time projection chamber detector takes data at a shallow depth as the far detector of the Short Baseline Neutrino program at Fermilab, searching for sterile neutrinos with the Booster and Main Injector neutrino beams. The ICARUS trigger system exploits [...] Read more.

The ICARUS-T600 liquid argon time projection chamber detector takes data at a shallow depth as the far detector of the Short Baseline Neutrino program at Fermilab, searching for sterile neutrinos with the Booster and Main Injector neutrino beams. The ICARUS trigger system exploits the temporal coincidence of the beams with scintillation light signals detected by 360 photo-multiplier tubes in limited TPC regions. The trigger efficiency measurement leverages cosmic rays collected without any scintillation light requirement, with timing from an external cosmic ray tagger system. The efficiency measured with stopping muons roughly saturates at

E_{μ}

∼300 MeV, covering most of the expected energy range of charged-current neutrino interactions. For the latest ICARUS physics runs, special “adder” boards performing the analog sum of light signals were introduced as a complementary trigger to possibly recover low-energy neutrino interactions. Full article

(This article belongs to the Special Issue Selected Papers from the 13th International Conference on New Frontiers in Physics (ICNFP 2024))

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6 pages, 3992 KiB

Open AccessArticle

The Effect of Gravity on Antimatter: The ALPHA Experiment

by Germano Bonomi

Particles 2025, 8(1), 20; https://doi.org/10.3390/particles8010020 - 20 Feb 2025

Viewed by 499

Abstract

Although the gravitational interaction between matter and antimatter has been the subject of theoretical speculation since the discovery of the latter in 1928, only recently was the ALPHA experiment at CERN able to observe, for the first time, the effects of gravity on [...] Read more.

Although the gravitational interaction between matter and antimatter has been the subject of theoretical speculation since the discovery of the latter in 1928, only recently was the ALPHA experiment at CERN able to observe, for the first time, the effects of gravity on antimatter atoms, namely on antihydrogen. After an introduction of the concept of antimatter, along with its still-unresolved mysteries, details about how antihydrogen is produced at the Antimatter Factory at CERN will be given. Finally, the measurement of the acceleration of gravity of antihydrogen atoms falling in the Earth’s gravitational field will be described. Full article

(This article belongs to the Special Issue Selected Papers from the 13th International Conference on New Frontiers in Physics (ICNFP 2024))

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16 pages, 5186 KiB

Open AccessArticle

ICARUS at the Short-Baseline Neutrino Program: First Results

by Maria Artero Pons

Particles 2025, 8(1), 18; https://doi.org/10.3390/particles8010018 - 14 Feb 2025

Viewed by 497

Abstract

The ICARUS collaboration employed the 760-ton T600 detector in a successful three-year physics run at the underground LNGS laboratory. In 2021, ICARUS started its new operation at Fermilab, collecting a substantial amount of neutrino events from the Booster Neutrino Beam (BNB) and the [...] Read more.

The ICARUS collaboration employed the 760-ton T600 detector in a successful three-year physics run at the underground LNGS laboratory. In 2021, ICARUS started its new operation at Fermilab, collecting a substantial amount of neutrino events from the Booster Neutrino Beam (BNB) and the neutrinos at the Main Injector (NuMI) beam off-axis. These were used to test the ICARUS event selection, reconstruction, and analysis algorithms. ICARUS successfully completed its commissioning phase in June 2022, moving then to data taking for neutrino oscillation physics, aiming at first to either confirm or refute the claim by the Neutrino-4 short-baseline reactor experiment. ICARUS will also perform measurements of neutrino cross sections in LAr with the NuMI beam and several Beyond Standard Model studies. After the first year of operations, ICARUS will search for evidence of sterile neutrinos jointly with the Short-Baseline Near Detector, within the Short-Baseline Neutrino program. In this work, preliminary results from the ICARUS data with the BNB and NuMI beams are presented, both in terms of the performance of all ICARUS subsystems and the capability to select and reconstruct neutrino events. Full article

(This article belongs to the Special Issue Selected Papers from the 13th International Conference on New Frontiers in Physics (ICNFP 2024))

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8 pages, 8724 KiB

Open AccessArticle

The ATLAS Inner Tracker Strip Detector System for the Phase-II Large Hadron Collider Upgrade

by Emily Duden

Particles 2025, 8(1), 16; https://doi.org/10.3390/particles8010016 - 12 Feb 2025

Viewed by 488

Abstract

ATLAS is currently preparing for the HL-LHC upgrade, with an all-silicon Inner Tracker (ITk) that will replace the current Inner Detector. The ITk will feature a pixel detector surrounded by a strip detector, with the strip system consisting of four barrel layers and [...] Read more.

ATLAS is currently preparing for the HL-LHC upgrade, with an all-silicon Inner Tracker (ITk) that will replace the current Inner Detector. The ITk will feature a pixel detector surrounded by a strip detector, with the strip system consisting of four barrel layers and 12 endcap disks. After successful completion of a large-scale prototyping program, final design reviews have been completed in key areas, such as sensors, modules, front-end electronics, and ASICs. We present an overview of the strip system and highlight the final design choices of sensors, modules, and ASICs. We summarize the results achieved during prototyping and the current status of production and pre-production on various detector components, with an emphasis on QA and QC procedures. Full article

(This article belongs to the Special Issue Selected Papers from the 13th International Conference on New Frontiers in Physics (ICNFP 2024))

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9 pages, 3080 KiB

Open AccessArticle

Long-Term Ageing Studies on Eco-Friendly Resistive Plate Chamber Detectors

by Marcello Abbrescia, Giulio Aielli, Reham Aly, Maria Cristina Arena, Mapse Barroso Ferreira, Filho, Luigi Benussi, Stefano Bianco, Fabio Bordon, Davide Boscherini, Alessia Bruni, Salvatore Buontempo, Mattia Busato, Paolo Camarri, Roberto Cardarelli, Liliana Congedo, Marilisa De Serio, Francesco Debernardis, Anna Di Ciaccio, Luigi Di Stante, Pascal Dupieux, Jan Eysermans, Alessandro Ferretti, Martino Gagliardi, Giuliana Galati, Sara Garetti, Roberto Guida, Giuseppe Iaselli, Baptiste Joly, Stefania Alexandra Juks, Umesh Lakshmaiah, KyongSei Lee, Barbara Liberti, Dalia Lucero Ramirez, Beatrice Mandelli, Samuel Pierre Manen, Lorenzo Massa, Alessandra Pastore, Enrico Pastori, Davide Piccolo, Luca Pizzimento, Alessandro Polini, Giorgia Proto, Gabriella Pugliese, Luca Quaglia, Dayron Ramos, Gianluca Rigoletti, Alessandro Rocchi, Marino Romano, Paola Salvini, Amrutha Samalan, Rinaldo Santonico, Giovanna Saviano, Marco Sessa, Saverio Simone, Livia Terlizzi, Michael Tytgat, Ermanno Vercellin, Mattia Verzeroli and Nikolaos Zaganidis Show full author list Hide full author list

Particles 2025, 8(1), 15; https://doi.org/10.3390/particles8010015 - 11 Feb 2025

Viewed by 424

Abstract

In high-energy physics, resistive plate chamber (RPC) detectors operating in avalanche mode make use of a high-performance gas mixture. Its main component, Tetrafluoroethane (C₂H₂F₄), is classified as a fluorinated greenhouse gas. The RPC EcoGas@GIF++ collaboration is pursuing [...] Read more.

In high-energy physics, resistive plate chamber (RPC) detectors operating in avalanche mode make use of a high-performance gas mixture. Its main component, Tetrafluoroethane (C₂H₂F₄), is classified as a fluorinated greenhouse gas. The RPC EcoGas@GIF++ collaboration is pursuing an intensive R&D on new gas mixtures for RPCs to explore eco-friendly alternatives complying with recent European regulations. The performance of different RPC detectors has been evaluated at the CERN Gamma Irradiation Facility with Tetrafluoropropene (C₃H₂F₄)-CO₂-based gas mixtures. A long-term ageing test campaign was launched in 2022, and since 2023, systematic long-term performance studies have been carried out thanks to dedicated beam tests. The results of these studies are discussed together with their future perspectives. Full article

(This article belongs to the Special Issue Selected Papers from the 13th International Conference on New Frontiers in Physics (ICNFP 2024))

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14 pages, 2305 KiB

Open AccessArticle

Spin Physics at PHENIX

by Devon Loomis

Particles 2025, 8(1), 14; https://doi.org/10.3390/particles8010014 - 10 Feb 2025

Viewed by 505

Abstract

Situated at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory, the PHENIX experiment has for almost two decades been at the forefront of investigations into spin structure and dynamics in high-energy nuclear physics. Although decommissioned in 2016, the PHENIX collaboration has [...] Read more.

Situated at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory, the PHENIX experiment has for almost two decades been at the forefront of investigations into spin structure and dynamics in high-energy nuclear physics. Although decommissioned in 2016, the PHENIX collaboration has released a number of new results over the past several years that continue to inform the field. Recent longitudinal spin measurements uncover the role of gluon and sea quark polarization in the proton. Transverse spin measurements probe the transverse momentum-dependent (TMD) distributions and higher-twist multiparton correlators that are needed to fully explain partonic dynamics in the initial and final state. Additionally, the effects of heavy ions on spin have been studied by comparing transverse spin measurements between p+p and p+A collisions. These recent results and their wider implications are presented. Full article

(This article belongs to the Special Issue Selected Papers from the 13th International Conference on New Frontiers in Physics (ICNFP 2024))

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8 pages, 11915 KiB

Open AccessArticle

Development of the NUCLEUS Detector to Explore Coherent Elastic Neutrino-Nucleus Scattering

by Nicole Schermer

Particles 2025, 8(1), 8; https://doi.org/10.3390/particles8010008 - 22 Jan 2025

Viewed by 720

Abstract

The NUCLEUS experiment, currently being commissioned at the Technical University of Munich, is designed to observe coherent elastic neutrino-nucleus scattering (

CE ν NS

) from reactor neutrinos and measure its cross-section with a percent-level precision at recoil energies below

100 eV

[...] Read more.

The NUCLEUS experiment, currently being commissioned at the Technical University of Munich, is designed to observe coherent elastic neutrino-nucleus scattering (

CE ν NS

) from reactor neutrinos and measure its cross-section with a percent-level precision at recoil energies below

100 eV

. As a Standard Model process,

CE ν NS

provides a unique probe into neutrino properties, potential new physics, and background suppression techniques relevant to dark matter experiments. The experiment utilizes gram-scale cryogenic calorimeters operating at

10 mK

with an energy threshold of

20 eV

. Situated at a shallow overburden of 3 m of water equivalent, the experimental site necessitates an advanced shielding strategy combining active vetoes and passive layers to reduce background rates to approximately

100 counts / (kg \cdot day \cdot keV)

, as confirmed by full setup simulations. The commissioning phase has successfully demonstrated the stable operation of the cryogenic target detectors, achieving baseline resolutions below

10 eV

, and the integration of the various shielding systems. Following this milestone, the experiment is set to transition to the EdF Chooz B nuclear reactor in France in 2025, where it will enable precise measurements of

CE ν NS

, contributing to the understanding of neutrino interactions and advancing the field of astroparticle physics. Full article

(This article belongs to the Special Issue Selected Papers from the 13th International Conference on New Frontiers in Physics (ICNFP 2024))

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6 pages, 4345 KiB

Open AccessArticle

The HIBEAM Experiment

by Alexander Burgman

Particles 2025, 8(1), 6; https://doi.org/10.3390/particles8010006 - 16 Jan 2025

Viewed by 498

Abstract

The violation of baryon number is an essential ingredient for baryogenesis—the preferential creation of matter over antimatter—needed to account for the observed baryon asymmetry in the universe. However, such a process has yet to be experimentally observed. The HIBEAM/NNBAR program is a proposed [...] Read more.

The violation of baryon number is an essential ingredient for baryogenesis—the preferential creation of matter over antimatter—needed to account for the observed baryon asymmetry in the universe. However, such a process has yet to be experimentally observed. The HIBEAM/NNBAR program is a proposed two-stage experiment at the European Spallation Source to search for baryon number violation. The program will include high-sensitivity searches for processes that violate baryon number by one or two units as follows: free neutron–antineutron oscillation via mixing, neutron–antineutron oscillation via regeneration from a sterile neutron state, and neutron disappearance; the effective process of neutron regeneration is also possible. The program can be used to discover and characterize mixing in the neutron, antineutron, and sterile neutron sectors. The experiment addresses topical open questions such as the origins of baryogenesis and the nature of dark matter, and it is sensitive to scales of new physics that substantially exceed those available at colliders. A goal of the program is to open a discovery window to neutron conversion probabilities (sensitivities) by up to three orders of magnitude compared with previous searches, which is a rare opportunity. A conceptual design report for NNBAR has recently been published. Full article

(This article belongs to the Special Issue Selected Papers from the 13th International Conference on New Frontiers in Physics (ICNFP 2024))

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7 pages, 473 KiB

Open AccessArticle

An Overview of the CMS High Granularity Calorimeter

by Bora Akgün

Particles 2025, 8(1), 4; https://doi.org/10.3390/particles8010004 - 11 Jan 2025

Viewed by 582

Abstract

Calorimetry at the High Luminosity LHC (HL-LHC) faces many challenges, particularly in the forward direction, such as radiation tolerance and large in-time event pileup. To meet these challenges, the CMS Collaboration is preparing to replace its current endcap calorimeters from the HL-LHC era [...] Read more.

Calorimetry at the High Luminosity LHC (HL-LHC) faces many challenges, particularly in the forward direction, such as radiation tolerance and large in-time event pileup. To meet these challenges, the CMS Collaboration is preparing to replace its current endcap calorimeters from the HL-LHC era with a high-granularity calorimeter (HGCAL), featuring an unprecedented transverse and longitudinal segmentation, for both the electromagnetic and hadronic compartments, with 5D information (space–time–energy) read out. The proposed design uses silicon sensors for the electromagnetic section (with fluences above

10^{16} n_{e q} {/cm}^{2}

) and high-irradiation regions (with fluences above

10^{14} n_{e q} {/cm}^{2}

) of the hadronic section, while in the low-irradiation regions of the hadronic section, plastic scintillator tiles equipped with on-tile silicon photomultipliers (SiPMs) are used. Full HGCAL will have approximately 6 million silicon sensor channels and about 280 thousand channels of scintillator tiles. This will allow for particle-flow-type calorimetry, where the fine structure of showers can be measured and used to enhance particle identification, energy resolution and pileup rejection. In this overview we present the ideas behind HGCAL, the current status of the project, results of the beam tests and the challenges that lie ahead. Full article

(This article belongs to the Special Issue Selected Papers from the 13th International Conference on New Frontiers in Physics (ICNFP 2024))

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9 pages, 15387 KiB

Open AccessArticle

The Transmission Muography Technique for Locating Potential Radon Gas Conduits at the Temperino Mine (Tuscany, Italy)

by Diletta Borselli, Tommaso Beni, Lorenzo Bonechi, Debora Brocchini, Nicola Casagli, Roberto Ciaranfi, Vitaliano Ciulli, Raffaello D’Alessandro, Andrea Dini, Catalin Frosin, Giovanni Gigli, Sandro Gonzi, Silvia Guideri, Luca Lombardi, Massimiliano Nocentini, Andrea Paccagnella and Simone Vezzoni

Particles 2025, 8(1), 3; https://doi.org/10.3390/particles8010003 - 11 Jan 2025

Viewed by 585

Abstract

Transmission muography is an imaging technique that allows us to obtain two-dimensional and three-dimensional average-target density images by measuring the transmission of atmospheric muons. Through this technique, it is possible to observe density anomalies inside a target volume and locate them three-dimensionally. In [...] Read more.

Transmission muography is an imaging technique that allows us to obtain two-dimensional and three-dimensional average-target density images by measuring the transmission of atmospheric muons. Through this technique, it is possible to observe density anomalies inside a target volume and locate them three-dimensionally. In this work, the potential of the technique will be illustrated through the description of the results of two measurements carried out in the tourist path of the Temperino mine (Livorno, Italy) in an area where a higher concentration of Radon gas is measured. This section of the gallery, located at a depth of about 50 m and dating back to the Etruscan period, might contain ancient cavities not yet discovered that could represent preferential conduits into which Radon gas is released into the tourist route. The muographic results are illustrated, focusing on the search for low-density anomalies attributable to cavities. The measurements are part of the MIMA-SITES project aimed at ensuring the safety of specific zones within the Temperino mine. Full article

(This article belongs to the Special Issue Selected Papers from the 13th International Conference on New Frontiers in Physics (ICNFP 2024))

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10 pages, 5511 KiB

Open AccessReview

Multimessenger Studies with the Pierre Auger Observatory

by Jon Paul Lundquist and the Pierre Auger Collaboration

Particles 2025, 8(2), 45; https://doi.org/10.3390/particles8020045 - 22 Apr 2025

Viewed by 103

Abstract

The Pierre Auger Observatory, the world’s largest ultra-high-energy (UHE) cosmic ray (CR) detector, plays a crucial role in multi-messenger astroparticle physics with its high sensitivity to UHE photons and neutrinos. Recent Auger Observatory studies have set stringent limits on the diffuse and point-like [...] Read more.

The Pierre Auger Observatory, the world’s largest ultra-high-energy (UHE) cosmic ray (CR) detector, plays a crucial role in multi-messenger astroparticle physics with its high sensitivity to UHE photons and neutrinos. Recent Auger Observatory studies have set stringent limits on the diffuse and point-like fluxes of these particles, enhancing constraints on dark-matter models and UHECR sources. Although no temporal coincidences of neutrinos or photons with LIGO/Virgo gravitational wave events have been observed, competitive limits on the energy radiated in these particles have been established, particularly from the GW170817 binary neutron star merger. Additionally, correlations between the arrival directions of UHECRs and high-energy neutrinos have been explored using data from the IceCube Neutrino Observatory, ANTARES, and the Auger Observatory, providing additional neutrino flux constraints. Efforts to correlate UHE neutron fluxes with gamma-ray sources within our galaxy continue, although no significant excesses have been found. These collaborative and multi-faceted efforts underscore the pivotal role of the Auger Observatory in advancing multi-messenger astrophysics and probing the most extreme environments of the Universe. Full article

(This article belongs to the Special Issue Selected Papers from the 13th International Conference on New Frontiers in Physics (ICNFP 2024))

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19 pages, 2832 KiB

Open AccessReview

Sixteen Years of Gamma-Ray Discoveries and AGN Observations with Fermi-LAT

by Fausto Casaburo, Stefano Ciprini, Dario Gasparrini and Federica Giacchino

Particles 2025, 8(1), 17; https://doi.org/10.3390/particles8010017 - 12 Feb 2025

Viewed by 612

Abstract

In June 2024, the Fermi Gamma-Ray Space Telescope (FGST) celebrated its 16th year of operations. The Fermi Large Area Telescope (Fermi-LAT) is the main instrument onboard the FGST satellite and is designed to be sensitive to

γ

-rays in the energy range from [...] Read more.

In June 2024, the Fermi Gamma-Ray Space Telescope (FGST) celebrated its 16th year of operations. The Fermi Large Area Telescope (Fermi-LAT) is the main instrument onboard the FGST satellite and is designed to be sensitive to

γ

-rays in the energy range from about

20 MeV

up to the

TeV

regime. From its launch, the Fermi-LAT has collected more than

4.53 billion

photon events, providing crucial information to improve our understanding of particle acceleration and

γ

-ray production phenomena in astrophysical sources. The most abundant in the last 4FGL-data release 4 (4FGL-DR4), most powerful and persistent

γ

-ray emitters in the sky are the Active Galactic Nuclei (AGNs). These sources are extremely luminous galaxy cores powered by a super massive black hole (SMBH) with a mass ranging from millions to billions of times the mass of the Sun. The ASI-SSDC, a facility of the Agenzia Spaziale Italiana (ASI), plays a pivotal role in supporting Fermi-LAT by providing the essential infrastructure for the storage, processing, and analysis of the vast amounts of data generated by the mission. As a key asset to various space missions, ASI-SSDC contributes significantly to advancing research in high-energy astrophysics and

γ

-ray observations. Full article

(This article belongs to the Special Issue Selected Papers from the 13th International Conference on New Frontiers in Physics (ICNFP 2024))

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7 pages, 308 KiB

Open AccessReview

Rare Decays in CMS

by Giacomo Fedi

Particles 2025, 8(1), 7; https://doi.org/10.3390/particles8010007 - 17 Jan 2025

Viewed by 419

Abstract

The CMS experiment at the LHC has advanced precision measurements of rare B-meson and charm decays, offering insights into phenomena beyond the Standard Model (SM). This paper highlights key results from Run 2 and Run 3 data, including the branching fraction and lifetime [...] Read more.

The CMS experiment at the LHC has advanced precision measurements of rare B-meson and charm decays, offering insights into phenomena beyond the Standard Model (SM). This paper highlights key results from Run 2 and Run 3 data, including the branching fraction and lifetime of

B_{s} \to μ^{+} μ^{-}

, angular analyses of

B^{0} \to K^{* 0} μ^{+} μ^{-}

, the first observation of

J / ψ \to μ^{+} μ^{-} μ^{+} μ^{-}

, and stringent limits on

D^{0} \to μ^{+} μ^{-}

. These findings provide tests of SM predictions while probing subtle hints of new physics. Full article

(This article belongs to the Special Issue Selected Papers from the 13th International Conference on New Frontiers in Physics (ICNFP 2024))

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9 pages, 1080 KiB

Open AccessReview

Lepton Flavour Universality Tests Using Semileptonic b-Hadron Decays at the LHCb Detector

by Bogdan Kutsenko

Particles 2025, 8(1), 5; https://doi.org/10.3390/particles8010005 - 14 Jan 2025

Viewed by 524

Abstract

This review highlights advancements in testing Lepton Flavour Universality (LFU) through semileptonic b-hadron decays at the LHCb detector. Measurements of the LFU

R (D)

and

R (D^{*})

provide evidence of deviations from Standard Model (SM) predictions, suggesting [...] Read more.

This review highlights advancements in testing Lepton Flavour Universality (LFU) through semileptonic b-hadron decays at the LHCb detector. Measurements of the LFU

R (D)

and

R (D^{*})

provide evidence of deviations from Standard Model (SM) predictions, suggesting the presence of possible New Physics (NP). However, the

D^{★}

longitudinal polarisation results are in good agreement with SM expectations, placing constraints on potential NP theories, such as the leptoquarks or charged Higgs models. Further improvements in the measurements’ precision are expected with the new data from LHCb Run 3, collected with higher instantaneous luminosity and improved trigger. Full article

(This article belongs to the Special Issue Selected Papers from the 13th International Conference on New Frontiers in Physics (ICNFP 2024))

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