Abstract Diffuse γ -ray emission is a key probe of cosmic-ray (CR) distribution within the Galaxy. However, the discrepancies between observations and theoretical model expectations highlight the need for refined uncertainty estimates. In the literature, spatial and temporal variability of lepton flux has been discussed as an uncertainty in diffuse γ -ray estimation. In the present work, we demonstrate that variability in the high-energy CR hadron flux is an important, yet previously underappreciated, source of uncertainty in diffuse γ -ray estimates. To assess this effect, we perform fully three-dimensional, time-dependent GALPROP simulations of CR protons injected from discrete Galactic sources. Our results reveal that the uncertainty in the hadronic component of diffuse γ rays is nonnegligible and can be comparable to, or even exceed, current experimental uncertainties at very high energies. This finding challenges the conventional assumption that only leptonic fluctuations are relevant to diffuse γ -ray modeling.

In the Large Hadron Collider (LHC), it is essential to provide repeatable High Energy Hadron (HEH) measurements with reduced uncertainty to accurately track HEH trends as a function of machine operations and tunnel configurations. This level of precision is crucial not only for understanding the machine’s behaviour, but also for defining radiation qualification requirements for systems installed in the accelerator. However, the CY62157EV30 (CY90), which is currently used as an HEH sensor in the RadMon system, exhibits significant variability in its measurements. This high uncertainty prevents effective trend identification, and safety margins of up to a factor of 10 should be applied when defining radiation requirements. By contrast, the CY62167GE30 (CY65) offers significantly lower intra-lot uncertainty and improved radiation performance, making it a promising alternative to the CY90. This work validates the measurements obtained using the CY65 and highlights the benefits its use would bring to the LHC and its operational reliability.

Understanding and monitoring the space environment is of great importance for the design and development of space avionics. This is especially critical when employing radiationsensitive Commercial-Off-The-Shelf (COTS) components in space systems. This work presents the design, validation and characterization of the SpaceRadMon-NG radiation monitoring payload and its sensors, a modular system built around such components. The study covers the payload configuration and preparations for the RADIOX (RADiation effects during In Orbit flight eXperiment) mission, part of the SYNDEO-1 CubeSat. Unique methodologies were applied for radiation qualification, system-level validation and sensor characterization to ensure reliable operation in space. The payload features enhanced capabilities compared to the previous version, including improved resolution, power efficiency and system modularity. Mechanical and radiation tests confirmed system robustness, and a cross-section smaller than 8.58·10−12 cm2 was determined at a 95% confidence level. Sensor performance was excellent, with relative errors of 0.65% for the COTS Static Random Access Memory (SRAM) and 0.41% for the Floating Gate DOSimeter (FGDOS) compared to reference devices. A novel FGDOS characterization under simultaneous temperature cycling and irradiation confirmed the stability of its temperature coefficient and identified an effective compensation method using a radiationinsensitive reference sensor. This compensation approach can be extended to other radiation-sensitive components in space. With its successful validation in space-representative environments, the payload is ready for in-orbit demonstration, where it will measure the Total Ionizing Dose (TID) and High Energy Hadron (HEH) fluence in Low Earth Orbit (LEO).

Abstract We present a systematic study of triple Higgs boson production at future high-energy hadron colliders, using the six- b -jet final state as a probe of the Higgs self-interactions. We conduct, under realistic detector smearing assumptions, both a traditional cut-based analysis, and a multivariate one using gradient boosting. The multivariate strategy is found to enhance sensitivity to beyond the Standard Model effects on the Higgs boson’s self-couplings, while preserving large signal event yields, thus enabling more robust statistical inference. This allows us to assess the impact of detector effects, systematic uncertainties, background normalisation, as well as different truncation choices in an effective-field-theory description of the new physics effects possibly affecting the Higgs boson’s self-interactions. Our results demonstrate that statistically-meaningful and perturbative-unitarity-compatible constraints on the trilinear and quartic Higgs boson self-couplings can be achieved, provided that systematic uncertainties are controlled at the few-percent level. Finally, we extrapolate our results to various collider energies and luminosities, demonstrating in particular that an 85 TeV proton-proton collider performs comparably to a 100 TeV machine. Altogether, our findings therefore establish the six- b channel as a viable probe of the Higgs self-interactions at most future hadron collider options currently being examined by the high-energy physics community.

Abstract The effective cross section of double parton scattering in high-energy hadron collisions has been measured in proton-proton collisions, with significant variation among final-state observables, contrary to the idea of a universal value. Building upon our previous work, we incorporate the dependence on both the parton longitudinal momentum fraction x and the process energy hard scale μ into the transverse part of the double parton distributions, using a Gaussian profile. Employing the experimental data from the LHC and Tevatron experiments (covering different processes, kinematic configurations, and center-of-mass energies), we perform a global fit of the model, extracting the parameters that describe the proton structure. With this result, it becomes possible to calculate the effective cross section for other observables, and we provide predictions for future measurements at the LHC.

By adopting a hadron-structure-oriented approach, we present and discuss the release of the novel OMG3Q1.0 set of collinear fragmentation functions for fully charmed, rare Ω baryons. Our methodology combines diquarklike proxy model inputs for both charm-quark and gluon channels, calculated at the initial energy scales, with a Dokshitzer-Gribov-Lipatov-Altarelli-Parisi evolution that ensures a consistent treatment of heavy-quark thresholds, following directly from the heavy-flavor nonrelativistic evolution scheme. We complement our work with a phenomenological study of next-to-leading logarithm/next-to-leading order plus resummed Ω3c plus jet distributions using (sym) at the HL-LHC and the future FCC. Unraveling the production mechanisms of rare, yet-unobserved hadrons, as provided by the OMG3Q1.0 functions, stands as a key asset for deepening our understanding of QCD at future high-energy hadron colliders.

The cooling storage ring external-target experiment is a large-scale nuclear physics experiment, which aims to study the physics of heavy-ion collisions at low temperatures and high baryon densities. A beam monitor (BM) is placed in the beam line to monitor the beam status and to improve the reconstruction resolution of the primary vertices. The radiation dose and particle fluence stemming from the beam interactions with gases and detector materials affect the performance of the sensors and electronics of BM. This paper uses FLUKA Monte Carlo code to simulate the radiation environment of BM detector. Radiation quantities including the total ionizing dose, 1 MeV neutron equivalent fluence, high-energy hadron flux, thermal neutron flux, and nuclear fragment flux are presented. Results of alternative simulation setups, including adding shielding layers inside the BM, are also investigated.

Hard-probe tomography of the quark-gluon plasma (QGP) in heavy ion collisions has long been a preeminent goal of the high-energy nuclear physics program. In service of this goal, the isotropic modification of jets and high-energy hadrons has been studied in great detail at the leading-power (eikonal) level, with effects originating from sub-eikonal <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"> <a:mrow> <a:mi mathvariant="script">O</a:mi> <a:mo>(</a:mo> <a:mi>μ</a:mi> <a:mo>/</a:mo> <a:mi>E</a:mi> <a:mo>)</a:mo> </a:mrow> </a:math> anisotropic interactions presumed to be small. We present the first investigation of sub-eikonal, collective-flow-induced asymmetric jet broadening (jet drift) in event-by-event <c:math xmlns:c="http://www.w3.org/1998/Math/MathML"> <c:mrow> <c:msqrt> <c:mi>s</c:mi> </c:msqrt> <c:mo>=</c:mo> <c:mn>5.02</c:mn> </c:mrow> </c:math> TeV PbPb collisions at the Large Hadron Collider using the Anisotropic Parton Evolution computational framework. We show that jet drift imparts a significant enhancement of elliptic flow ( <d:math xmlns:d="http://www.w3.org/1998/Math/MathML"> <d:msub> <d:mi>v</d:mi> <d:mn>2</d:mn> </d:msub> </d:math> ) larger than the experimental resolution and increases the mean acoplanarity for low- and intermediate-energy particles ( <e:math xmlns:e="http://www.w3.org/1998/Math/MathML"> <e:mrow> <e:msub> <e:mi>p</e:mi> <e:mi>T</e:mi> </e:msub> <e:mo>&lt;</e:mo> <e:mn>10</e:mn> </e:mrow> </e:math> GeV). Importantly, these modifications to hard-probe observables are shown to survive averaging over events and collision geometry. They couple to the collective flow of the medium seen by the jet and encode information about the QGP dynamics inaccessible to studies considering only isotropic, eikonal-level effects.

The cross sections for the single exclusive production of (pseudo)scalar and (pseudo)tensor hadrons, as well as of even-spin QED bound states formed by pairs of opposite-charge leptons or hadrons, are estimated for photon-fusion processes in ultraperipheral collisions (UPCs) of proton-proton, proton-nucleus, and nucleus-nucleus at the Relativistic Heavy-Ion Collider, Large Hadron Collider (LHC) and Future Circular Collider, as well as in proton-air interactions at the highest energies reached by cosmic rays impinging on Earth. The UPC cross sections are computed in the equivalent photon approximation with realistic photon fluxes from the charged form factors of proton, lead, gold, and nitrogen ions. The production of four types of even-spin systems are considered: quarkonium (spin-0, 2, 4 meson bound states, from the lightest <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"> <a:msup> <a:mi>π</a:mi> <a:mn>0</a:mn> </a:msup> </a:math> meson up to toponium), exotic hadrons (including candidate multiquark states), leptonium (positronium, dimuonium, and ditauonium), as well as mesonium (pionium, kaonium, D-onium, and B-onium) and baryonium (notably, protonium) QED atoms. The expected yields at the different colliders are presented for about 50 such even-spin composite resonances, for which the ALICE and LHCb experiments have potential reconstruction capabilities at the LHC. The impact of the diphoton decays of such even-spin states is also discussed as resonant backgrounds in the measurement of light-by-light scattering ( <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"> <c:mi>γ</c:mi> <c:mi>γ</c:mi> <c:mo stretchy="false">→</c:mo> <c:mi>γ</c:mi> <c:mi>γ</c:mi> </c:math> ) over <f:math xmlns:f="http://www.w3.org/1998/Math/MathML" display="inline"> <f:mrow> <f:msub> <f:mrow> <f:mi>m</f:mi> </f:mrow> <f:mrow> <f:mi>γ</f:mi> <f:mi>γ</f:mi> </f:mrow> </f:msub> <f:mo>≈</f:mo> <f:mn>0.1</f:mn> <f:mi>–</f:mi> <f:mn>15</f:mn> </f:mrow> </f:math> -GeV masses in Pb-Pb UPCs at the LHC.

Bound states of charm and anticharm quarks, known as charmonia, have a rich spectroscopic structure that can be used to probe the dynamics of hadron production in high-energy hadron collisions. Here, the cross section ratio of excited (ψ(2S)) and ground state (J/ψ) vector mesons is measured as a function of the charged-particle multiplicity in proton-lead (pPb) collisions at a center-of-mass (CM) energy per nucleon pair of 8.16TeV. The data corresponding to an integrated luminosity of 175 nb^{-1} were collected using the CMS detector. The ratio is measured separately for prompt and nonprompt charmonia in the transverse momentum range 6.5<p_{T}<30 GeV and in four rapidity ranges spanning -2.865<y_{CM}<1.935. For the first time, a statistically significant multiplicity dependence of the prompt cross section ratio is observed in proton-nucleus collisions. There is no clear rapidity dependence in the ratio. The prompt measurements are compared with a theoretical model which includes interactions with nearby particles during the evolution of the system. These results provide additional constraints on hadronization models of heavy quarks in nuclear collisions.

The RadMon system at CERN is a radiation monitoring solution designed for the accelerator complex and experimental areas, providing real-time, precise measurement of radiation levels impacting electronics. This paper presents the capabilities of the RadMon device, which measures Total Ionizing Dose (TID), Displacement Damage (DD) in silicon, High Energy Hadrons (HEH), and thermal neutron fluence. A distributed network of 500 RadMon units supports critical CERN infrastructure, offering enhanced resilience against radiation-induced failure, with a more than threefold improvement in system reliability over previous versions. The modular design accommodates remote, inaccessible locations, supporting diverse detector needs in challenging environments. Future upgrades focus on improving radiation and magnetic field tolerance, integrating IoT for wireless communication, and incorporating advanced dosimetry technologies, aligning the RadMon system with the rigorous demands of the upcoming High Luminosity LHC (HL-LHC) era.

Abstract This work demonstrates that once a large number of pion is condensed in a high-energy hadron collision, the gamma-ray spectrum from π 0 decay takes on a typical broken power-law shape, which has been documented in many astronomical observations, but we have not yet recognized it. We show that this pion condensation is caused by a large number of soft gluons condensed in protons.

Abstract The γ-ray emission from flat spectrum radio quasars (FSRQs), a subclass of blazars, is believed to be generated through interactions of high-energy leptons and/or hadrons in the jet with the ambient photon fields, including those from the accretion disk, the broad line region (BLR), and the dusty torus. However, these same photon fields can also attenuate γ-rays through internal photon–photon (γ–γ) absorption, imprinting characteristic spectral features. Investigating the internal absorption is crucial for unraveling the complex structure of FSRQs and constraining the poorly known location of the γ-ray emission region. In this study, we select a sample of γ-ray detected FSRQs with high redshift (z ≳ 3) to search for absorption features appearing at lower photon energies due to a substantial redshift. We extract the Fermi Large Area Telescope γ-ray spectra of these sources and perform physical modeling using a detailed γ–γ opacity model, assuming that the BLR photon field dominates the absorption and focusing on the energy range ∼25 GeV/(1 + z), where the absorption feature due to Lyα photons is expected. Our analysis reveals a hint of internal absorption for one source (the lowest redshift object in our sample, z ≃ 3) and provides constraints on the location of its γ-ray emitting region along the jet. For the remaining, higher-redshift sources, the limited photon statistics prevent a reliable detection of internal opacity features.

Understanding the internal structure of nucleons and nuclei has been a topic of enduring interest in high-energy physics. Gravitational form factors (GFFs) provide an important portal for us to probe the energy-momentum/mass distribution of nucleons and nuclei. This paper presents the study of the photon and gluon momentum GFFs, also known as the A-GFFs, of relativistic hadrons using the Weizsäcker-Williams method. To begin, we express the photon A-GFFs in terms of charge form factors and discuss the corresponding photon radius. Furthermore, an integral relation between the gluon A-GFF and the Laplacian of dipole scattering amplitude is derived in the small-x framework, and it allows us to unravel the gluon energy momentum distribution inside hadrons through measurements at the upcoming Electron-Ion Collider. In addition, we generalize the analysis to study the A-GFF of nuclei and propose employing the nuclear gluon mean square radius, together with the charge distribution, to constrain the neutron distribution for large nuclei. This work provides an interesting perspective into the fundamental structure of high-energy hadrons. Published by the American Physical Society 2025

The climate crisis and the degradation of the world's ecosystems require humanity to take immediate action. The international scientific community has a responsibility to limit the negative environmental impacts of basic research. The HECAP+ communities (High Energy Physics, Cosmology, Astroparticle Physics, and Hadron and Nuclear Physics) make use of common and similar experimental infrastructure, such as accelerators and observatories, and rely similarly on the processing of big data. Our communities therefore face similar challenges to improving the sustainability of our research. This document aims to reflect on the environmental impacts of our work practices and research infrastructure, to highlight best practice, to make recommendations for positive changes, and to identify the opportunities and challenges that such changes present for wider aspects of social responsibility.

The High-Granularity Calorimeter (HGCAL) will replace the current CMS Endcap Calorimeter during Long-Shutdown 3. The Endcap Concentrator (ECON) ASICs represent key elements in the readout chain, processing trigger (ECON-T) and data (ECON-D) streams from the HGCROC to the lpGBT. The ECONs will operate in a radiation environment with a High-Energy Hadron (E≥20 MeV) flux up to 2·107 cm-2s-1.This contribution describes the Universal Verification Methodology (UVM)-based functional verification of the ECON ASICs focusing on the re-use of existing components to manage the complexity of the verification environment.

This study investigates the performance of bent silicon crystals intended to channel hadrons in a fixed-target experiment at the Large Hadron Collider (LHC). The phenomenon of planar channelling in bent crystals enables extremely high effective bending fields for positively charged hadrons within compact volumes. Particles trapped in the potential well of high-purity, ordered atomic lattices follow the mechanical curvature of the crystal, resulting in macroscopic deflections. Although the bend angle remains constant across different momenta (i.e., the phenomenon is non-dispersive), the channelling acceptance and efficiency still depend on the particle momentum. Crystals with lengths in the range of 5 to 10 cm, bent to angles between 5 and 15 mrad, are under consideration for measurements of the electric and magnetic dipole moments of short-lived charmed baryons, such as the varLambda _c^+. Such large deflection angles over short distances cannot be achieved using conventional magnets. The principle of inducing spin precession through bent crystals for magnetic dipole moment measurements was first demonstrated experimentally in the 1990s. Building on this concept, experimental layouts are now being explored for implementation at the LHC. The feasibility of such measurements depends, among other factors, on the availability of crystals that exhibit the required mechanical properties to reach the necessary channelling performance. To address this, a dedicated machine experiment – TWOCRYST – has been installed in the LHC to carry out beam tests in the TeV energy range. The bent crystals for TWOCRYST were fabricated and tested using both X-ray diffraction and high-momentum hadron beams at 180 GeV/c at the CERN Super Proton Synchrotron (SPS) extraction lines. Two crystals based on established technologies were included in this test. In addition, a crystal bent via anodic bonding was tested for the first time with high-energy hadrons to assess its potential for future accelerator applications. This paper presents an analysis of the performance of the three tested crystals and, where possible, outlines key differences in their properties attributed to the respective bending techniques.

Strange hadron production provides information about the hadronisation process in high-energy hadron collisions. Strangeness enhancement has been interpreted as a signature of quark-gluon plasma formation in heavy-ion collisions, and recent observations of strangeness enhancement in small collision systems have challenged conventional hadronisation models. With its forward geometry and excellent particle identification capabilities, the LHCb detector is well-suited to study strangeness production in a unique kinematic region. Recent studies of strangeness production with the LHCb detector are presented, including measurements of strangeness enhancement in the charmand beauty-hadron systems.

Highly integrated multichannel readout electronics is crucial in contemporary particle physics experiments. A novel silicon photomultiplier readout system based on the VMM3a ASIC was developed, for the first time exploiting this chip for calorimetric purposes. To extend the dynamic range the signal from each SiPM channel was processed by two electronics channels with different gain. A fully operational prototype system with 256 SiPM readout channels allowed the collection of data from a prototype of the ALICE Forward Hadron Calorimeter (FoCal-H Prototype 2). The design and the test beam results using high energy hadron beams are presented and discussed, confirming the applicability of VMM3a-based solutions for energy measurements in a high rate environment.

Geant4: A game changer in high energy physics and related applicative fields