Future gravitational-wave observatories such as Einstein Telescope and Cosmic Explorer will require a substantial evolution of the laser frequency stabilization strategies currently employed in second-generation interferometric detectors. In Advanced Virgo and Advanced LIGO, residual laser frequency noise is strongly suppressed by feedback from the interferometer common-arm degree of freedom, whose long baseline provides an excellent frequency reference over most of the observation band. In third-generation detectors, however, the much longer arm cavities significantly reduce both the free spectral range and the coupled-cavity pole frequency, limiting the achievable bandwidth of the common-arm control loop and degrading the sensing-noise performance at high frequencies. As a consequence, the interferometer itself may no longer provide the broadband frequency stabilization presently achieved in second-generation instruments. This shifts a much larger fraction of the stabilization burden toward the input-optics system. In this review the implications of such a transition are discussed, with particular emphasis on long suspended input mode cleaners, multi-stage stabilization architectures, higher-order optical mode coupling, sensing-noise limitations, and optical layout considerations relevant for future detectors.
Laser-driven proton acceleration in hydrogen-rich media can be strongly modified by embedded plasmonic nanoantennas that localize electromagnetic energy on nanometer scales. The National Ignition Facility (NIF) project at the Lawrence Livermore National Laboratory has achieved 8.6 MJ of fusion energy output from an estimated 2 MJ of energy delivered to the target. This has led to several laser fusion startup projects. Most of these operate on the same principle as the NIF project: relatively slow, mechanical compression and the resulting large thermal temperature increase. Most often, cryogenically frozen deuterium–tritium fuel is used in this reaction. This initial conventional method has disadvantages. The strongly compressed target expands faster than the fusion burn from the ignited center, so only a small part of the target fuses, and slow mechanical instabilities may also develop. The NAPLIFE Collaboration uses another method with radiation-dominated limited compression, aiming for simultaneous ignition. This is achieved by nanotechnology; laser light absorption is regulated by resonant nanoantennas.
Measurements of charge-changing cross-sections were developed as a method for determining proton radii, particularly for unstable, short-lived nuclei. Such cross-sections must be measured with high precision to determine the precise charge radii. However, there are complexities in the experimental method leading to uncertainties in determining precise nuclear radii. Therefore, good models describing the complex physics of charged particle interactions are needed in order to validate the experimental method and to estimate the contribution of systematic uncertainties. GEANT4 is a Monte Carlo simulation code widely used to describe interactions in heavy-ion collisions over a broad energy range, ranging from atomic physics to cosmic-ray energies. Experimental measurements of charge-changing reactions for carbon isotopes 10,12C on different secondary targets were performed. In the present work, the experimental detector geometry, beam profile, and detector configuration were implemented in GEANT4 simulations in order to reproduce the experimental conditions as closely as possible. The experimentally obtained spectra are compared with the corresponding GEANT4 simulations to validate the interpretation of the measured spectra and assess systematic effects. Also, the secondary particle yield ratio is deduced and compared with GEANT4 results.
Nexus-NRS is an open, reproducible software tool for nuclear reaction calculations, implemented in a functional-programming style (Clojure); the underlying reaction theory is standard and pre-established, and the contribution here is the software: stable radial solvers for weakly bound (halo) states, scattering observables, and transfer reactions, packaged with optical-model potentials, Riccati–Numerov integration with regular near-origin initialization options, discrete Wronskian diagnostics for numerical stability, and a Distorted Wave Born Approximation (DWBA) implementation for single-nucleon transfer in the post form, extended with Austern-style multipole/angular ingredients. We report concrete validation results, with figures: near-origin Numerov starts (hybrid vs. finite) agree to better than 10−9 on a 11Be halo bound-state observable, discrete Wronskian drift is reduced by a factor of ∼6–7 by the hybrid start, and a single-threaded partial-wave scan runs within a factor of ∼1.4 of an equivalent NumPy implementation. We compare directly against DWUCK4 for 16O(d,p)17O radial integrals (same order of magnitude, residual disagreement diagnosed but not yet resolved), and against experimental data for 11Li(p,d)10Li populating an unbound p1/2 resonance, where an unfitted (S=1) quasi-bound-resonance DWBA calculation is tested against seven measured points with error bars. With the normalization absorbed into a single scale factor, it reproduces the shape over the forward angular range (χν2=2.1) but not over the full range (χν2=7.4). Nexus-NRS supports scripting/REPL-driven studies and an interactive web dashboard, of which a publicly accessible instance is deployed.
The effect of a tendency toward coplanarity of sub-cores in gamma-ray–hadron families, observed in high-mountainous and stratospheric experiments with X-ray emulsion chambers at super-high energies, is discussed. Based on simulations within the framework of the traditional FANSY 2.0/QGSJ model and the radical FANSY 2.0/2D model, the possibility of studying coplanar energy flows in the cores of Extensive Air Showers (EAS) arriving at the surface of the ADRON-55 calorimeter is considered. An assessment of the sensitivity of the ADRON-55 calorimeter for studying the coplanarity effect of energy flows in EAS cores has been made.
These notes comprise the material I presented during the International Workshop and School on Hadron Structure & Strong Interactions which took place in Nanjing in 2025. The aim of the lectures was to introduce and motivate the study of Generalised Parton Distributions (GPDs) for an audience of Master and Ph.D. students in hadron physics, with little to no background regarding the description of exclusive processes at high virtuality.
Based on nine years of flight data from the DArk Matter Particle Explorer (DAMPE) and a novel gamma-ray selection algorithm developed in previous work, we recalculate the instrument response functions (IRFs) in the 1–104 GeV energy range. We present PSF-weighted phase-folded light curves of the bright gamma-ray pulsars Vela and Geminga, obtained with an extended version of the PINT Is Not TEMPO2 (PINT) software adapted to our analysis needs. This work lays the groundwork for further refinement of the IRFs through pulsar analyses, improving DAMPE’s performance for gamma-ray astronomy and searches for potential dark-matter signatures.
The quantum motion of a photon in an arbitrary medium was considered within the framework of the gauge symmetry group SU(2)⊗U(1) using the Yang–Mills (Y-M) equations for Abelian fields. A system of second-order partial differential equations (PDEs) for the vector wave function of a photon is derived using the first-order Y-M equations as identities. The full wave function of a photon was defined as the arithmetic mean of the components of the wave function. In a particular case, an equation is obtained for its full wave function, taking into account the structure of space-time in a plane perpendicular to the direction of propagation of the photon. The quantum state of a photon in a nanowaveguide was investigated, and it is shown that under certain conditions, it is reduced to the problem of two coupled 1D quantum harmonic oscillators (QHO) with variable frequencies. An explicit expression is obtained for the wave function of a photon, which is characterized by two vibrational quantum numbers. A quantum theory of a photon for a dissipative medium has been developed taking into account the processes of absorption and emission of photons. The mathematical expectation (ME) of the photon wave function is constructed as the product of two 2D integral representations in which the integrand is the solution of a system of two coupled second-order PDEs. The ME of the probability amplitude of the transition of a single-photon state into one of the two-photon entangled Bell states is constructed. Finally, it was proven that, in addition to frequency, spin, momentum and polarization, the photon also has a spatial structure responsible for the cross sections of processes in which this massless fundamental particle participates.
In order to describe the heavy ion collision dynamics which implies the formation of hot and very dense nuclear matter in the overlapping region of the two colliding nuclei, we used simulated numerical calculations for FAIR available energies. We used the anti-kT jet-detection algorithm for highlighting the main directions of flow in Au-Au collisions at CBM energies, thus obtaining structures of the events depending on the number of flow streams. The jet-finder algorithm identified domains in the y-psi (rapidity-azimuthal angle) plane, where the number of charged particles, momenta and energy take higher values compared to other areas of this plane. The anisotropic flow coefficients vn may offer information about the pressure gradients in the early stages of the collision and about the high-density nuclear matter properties. The observation of K+ mesons in heavy ion collisions is of interest since K+ mesons, due to their strangeness, have a mean free path that exceeds the dimensions of the "fireball". In the numerical calculations the interval of rapidity 0
20Na is a well-known β-delayed α emitter, owing to the large decay energy of 20Na above the α + 16O threshold in the A=5α daughter nucleus 20Ne. In this work, the decay property of 20Na is investigated in detail via the β-γ β-α and β-γ-α coincidence spectroscopy. As the day-one experiment of the Beijing Rare Isotope Facility (BRIF), the intense 20Na beam was produced using the Isotope Separator On Line (ISOL) technique through the 100 MeV proton bombarding a stack of MgO as a thick target. Specific interest was focused on the exotic decay mode of 20Na; the previously reported low-energy α lines at 713 and 846 keV were confirmed, and several weak β-γ-α decay sequences were clearly identified for the first time, thanks to the strong resolving power of α-γ coincidence spectroscopy. The decay properties of 20Na are compared to the shell model calculation, which agree reasonably well with the allowed β transition strengths and subsequent electro-magnetic transitions with the use of the sd shell-model space with the USDB interaction.
In this contribution to the Halo-40 Proceedings, we discuss two topics regarding halo phenomena. The first is the pairing anti-halo effect on the neutron radius of halo nuclei and the restoration of the halo due to the cancellation between the anti-halo effect and the continuum coupling; the second is the soft dipole excitation of deformed halo nuclei. We demonstrate the importance of Hartree–Fock–Bogoliubov and relativistic Hartree–Bogoliubov theory in a continuum for properly taking into account the halo nature of extended wave functions in the calculations of neutron radii as well as the soft dipole excitations of halo nuclei. It is shown that the anti-halo effect is very sensitive to the continuum coupling induced by Bogoliubov-type quasi-particles, which largely cancels the anti-halo effect on the neutron radius. The soft dipole excitations of deformed halo nuclei 31Ne and 37Mg are discussed within the deformed Woods–Saxon model. We point out that the sharp peak just above the threshold in the dipole response is created by the halo effect, and its strength can be used to identify the magnitude of deformation and the halo configuration in the Nilsson-level scheme.
We study the thermodynamics of the (2+1)-dimensional Gross–Neveu model inspired from graphene. We focus on the entropy density of the Gaussian fluctuation beyond the mean field. The full in-medium, momentum-dependent evaluation reveals that the fluctuations give a substantial contribution, even comparable to that of the mean field. We argue that the back-reaction from the fluctuations to the mean field should be included, which reduces the contribution mainly coming from the Landau-damping region. To treat this self-consistently, we use the generalized version of the Beth–Uhlenbeck approach for the entropy density. Compared with the standard Beth–Uhlenbeck formulation, the generalized version suppresses the low-energy contributions while preserving the bound-state effects. To illustrate this, we consider the respective contributions of the bound excitons and unbound fermions to the total entropy. This shows a sharper crossover between the degrees of freedom compared to the standard Beth–Uhlenbeck approach. This behavior is consistent with Mott-transition physics in two-dimensional materials.
We present a short review dedicated to low-lying meson states. We present all meson nonets, which consist from up, down and strange light quarks. We consider the scalar nonet as a basic nonet. We work in the framework of the massless Nambu–Jona-Lasinio UR(3)×UL(3) quark model. The collective meson states are described through initially bare quark–antiquark pairs, whose condensates lead simultaneously to spontaneous breaking of the chiral and the flavour symmetry. After quantisation and the spontaneous breaking of the chiral symmetry, when quarks obtain constituent nonzero masses, they become dressed. We present an explanation of the inverse mass hierarchy of the low-lying nonet of the scalar mesons. The proposed explanation is based on symmetry principles. It is shown that, due to the flavour symmetry breaking, two isodoublets of K0*(700) mesons play the role of Goldstone bosons. It is also proven that there exists a solution with almost degenerate masses of the a0(980) and f0(980) mesons and a zero mass of the f0(500) meson. Short description of the physical properties of other meson nonets is provided. In particular unique mass relations among the different nonets, which are experimentally confirmed, are presented.
Advanced Doppler-shift methods for the calculation of the γ-ray lineshape registered in recoil-distance Doppler-shift and Doppler-shift attenuation methods are presented, emphasizing the case using a gate set on the shifted part of a direct feeding transition. For the precise description of the γ-ray lineshape, the process of evaporation of light particles from the compound nucleus has to be taken into account in the case of heavy ion-induced fusion-evaporation reactions. In addition, the impact of different approaches for calculating stopping powers is investigated in the process of the lifetime determinations. In the RDDS experiments, the γ-emission during the slowing down in the stopper is discussed in detail. Applications of the new procedures are demonstrated in two experiments: the first one is a plunger experiment performed in order to check for chirality in the 134Pr nucleus and the second one is a DSAM experiment conducted to test the isospin symmetry in 31P and 31S mirror nuclei.
The primary objective of this study is a comprehensive investigation of the self-bound properties of strange quark matter (SQM), which is hypothesized to represent the absolute ground state of superdense strongly interacting matter. An analysis is performed within the framework of the MIT bag model, including first-order perturbative QCD corrections and the finite strange quark mass. By systematically varying the vacuum pressure (bag constant, B) and the strong coupling constant (αc) over a broad parameter space, while assuming a finite strange quark mass (ms≠0), we explicitly compute the thermodynamic characteristics of the system including pressure, energy density, baryon number density, and the chemical potentials of quarks and charge-neutralizing electrons under conditions of β-equilibrium and global charge neutrality. Particular emphasis is placed on determining the minimum energy per baryon, which serves as the criterion for absolute stability. For parameter sets satisfying the self-binding condition, the integral properties of strange stars are derived via the numerical integration of the Tolman–Oppenheimer–Volkoff equations. The resulting mass–radius and mass–central density relations are analyzed, yielding the maximum stellar masses in the range (1.9−2.4)M⊙ . This study identifies the regions in the space of phenomenological parameters that allow for pure self-bound strange stars and demonstrates the sensitivity of stability and stellar properties to the underlying bag model parameters.
The experimental exploration of halo nuclei over the past four decades has established ground-state halo phenomena in about twenty nuclei, providing important benchmarks for modern nuclear theories. The deformed relativistic Hartree–Bogoliubov theory in continuum (DRHBc) has been successfully applied to describe known halo nuclei and to predict new candidates during the last dozen years. In this work, the possible two-neutron halo nuclei F29 and F31 are investigated within the DRHBc framework. In the spherical limit, an inversion between the 2p3/2 and 1f7/2 orbitals is obtained relative to the conventional single-particle ordering, which plays a crucial role in the formation of deformed halos in these nuclei. Assuming a prolate deformation with β2≈0.4, as suggested in previous studies, a deformed two-neutron halo in F29 is reproduced. For F31, a well-deformed ground state with β2≈0.24 and a more pronounced two-neutron halo emerge self-consistently.
In this paper, we first show that the four masses of the Upsilon binding states—namely, Y(1S) through Y(4S)—composed of bottom quarks and anti-bottom quarks follow logarithmic spacing. The correlation coefficient R between the experimental values and the straight line is 0.99997, indicating an extremely good fit. When the three peaks—Y(5S), Y(6S), and Y(7S), considered higher Upsilon binding states, as indicated in the recent Belle experiment—are added and plotted on the line of logarithmic spacing, the correlation coefficient R between the straight line and the experimental values for these seven “binding state levels” is 0.9998. If this line is extended to higher masses, an eighth peak in the cross-section is expected at a mass of (11,119 ± 10) MeV. In other words, it is predicted that the peak in the cross-section created by Y(8S) will be found in the Belle experiment in the future. Next, we consider why meson binding states are represented by a line with logarithmic spacing. An example is the electric field generated by a charge on a two-dimensional plane; the electric field created by a charge placed on the plane is expressed as F∼1/r, and the potential energy is expressed as V∼log(r). Therefore, we solve the two-dimensional Schrödinger equation numerically under F∼1/r and compare the results with the three-dimensional solution. We find that differences appear in the energy levels of the J=0ηc meson. Specifically, it is shown that the mass of the ηc meson is closer to the value obtained by solving the two-dimensional Schrödinger equation. Based on this ηc meson series, we predict the existence of a new ηc meson with a mass of 3955 MeV.
Metallic nanoantennas are promising structures for enhancing energy transfer in high-intensity laser–matter interactions, especially in nanoplasmonic-assisted fusion. Under ultrashort laser pulses, they generate strong localized fields, modify ionization dynamics, and significantly affect charge acceleration in dense media. In this work, we present a comprehensive particle-in-cell (PIC) study of gold nanoantennas of various geometries—dipoles, planar crosses, three-dimensional crosses, and Yagi-inspired planar structures—irradiated by near-infrared femtosecond pulses at intensities at a range of ~4 × 1017–4 × 1018 W/cm2. The antenna structures are embedded in a dense hydrogen-rich medium, allowing us to follow electron emission, gold ionization, and proton acceleration self-consistently. Crossed and Yagi-type geometries exhibit more robust resonant behavior than dipoles, with higher field localization and greatly reduced sensitivity to incident polarization. The proton energies increase to ~200 keV at 4 × 1017 W/cm2, and saturate around ~300 keV at a higher intensity >~4 × 1018 W/cm2, dependent on the geometry. This happens largely due to a rapid loss of conduction electrons from the gold structures. Our results highlight Yagi-based and cross-based nanoantennas as promising resonant dopes for laser-driven energy coupling and point toward optimized multi-arm architectures for future nanofusion-target engineering applications.
Heavy radioactive ion beams produced by in-flight techniques often involve long-lived excited states (isomers). This presents a challenge for reaction studies because none of the existing fragment separators worldwide can resolve isomers in-flight. Here, we propose a novel scheme to produce tagged cocktail beams or pure isomer beams using an ion storage ring. The mass resolving powers of storage rings enable us to identify and separate ions of the isomeric state from the corresponding ground state in a secondary beam. For short-lived isomers, the Rare-RI Ring (R3) facility at the RI Beam Factory (RIBF) will be available, while for long-lived isomers the Experimental Storage Ring (ESR) at the GSI/FAIR facility will be utilized. Isomers often have spins and deformations significantly different from the ground states. Studying isomer structures will provide unique insight into their specific interactions, opening a new frontier in reaction studies with radioactive ion beams in the coming years.
The Large Hadron Collider forward (LHCf) experiment studies the production of neutral particles in the very forward region of high-energy hadronic collisions at the LHC. These measurements provide essential calibration data for hadronic interaction models used in simulations of extensive air showers initiated by ultra-high-energy cosmic rays. The LHCf experiment measures forward-produced neutral particles, such as neutrons, photons, π0, and η mesons, which play a key role in the development of extensive air showers. Proton–proton collisions at the LHC reach center-of-mass energies up to 13.6 TeV, corresponding in the fixed-target frame to cosmic-ray interactions at energies close to 1017 eV in the Earth’s atmosphere. LHCf has collected data in proton–proton collisions at several energies, as well as in proton–lead collisions, enabling detailed comparisons between experimental results and predictions of hadronic interaction models. This contribution reviews the most significant LHCf results, with emphasis on Run II proton–proton data at s=13TeV, including measurements of forward neutron, photon, and η meson production. Finally, future prospects are discussed, focusing on ongoing analyses of Run III proton–proton data at s=13.6TeV and on the final LHCf operation in proton-oxygen collisions at sNN=9.6TeV, which best reproduces cosmic-ray interactions with nuclei of the Earth’s atmosphere.
