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This article presents the development and validation of a hybrid multi-sphere discrete element framework - Rigid3D, for the simulation of granular systems with arbitrarily shaped particles in 3D space. In this DEM framework, a non-spherical particle is approximated by three different geometric models: (1) multi-sphere model with overlapping spheres (MS model), (2) particle surface with triangle mesh (surface model), and (3) discretized particle body with polyhedral cells (cell model). The multi-sphere approach will be the "engine" for efficient DEM simulations, while the particle's mesh and cell models will be updated simultaneously according to the position and orientation of their associated MS model, for use in particle-related inter-phase couplings in a multi-phase flow. In this sense, Rigid3D tries to combine the best of both worlds in multi-sphere and polyhedral DEMs: multi-sphere method for the efficiency and acceptable accuracy in the DEM simulation of granular flows, while the surface and cell models for the couplings between particles and other phases (continuous or dispersed phases) without affecting the performance of DEM simulations.

This paper introduces a new paradigm that integrates the concepts of particle abrasion and breakage. Both processes can co-occur under loading as soil particles are subjected to friction as well as collisions between particles. Therefore, the significance of this integrating paradigm lies in its ability to address both abrasion and breakage in a single framework. The new paradigm is mapped out in a framework called the 'particle geometry space.' The x-axis corresponds to the surface-area-to-volume ratio ($A/V$), while the y-axis represents volume ($V$). This space facilitates a holistic characterization of the four-particle geometry features, i.e., shape ($β$) and size ($D$) as well as surface area ($A$) and volume ($V$). Three distinct paths (abrasion, breakage, and equally-occurring abrasion and breakage processes), three limit lines (breakage line, sphere line, and average shape-conserving line), and five different zones are defined in the particle geometry space. Consequently, this approach enables us to systematically relate the extent of co-occurring abrasion and breakage to the particle geometry evolution.

We study the dynamics of one-particle and few-particle billiard systems in containers of various shapes. In few-particle systems, the particles collide elastically both against the boundary and against each other. In the one-particle case, we investigate the formation and destruction of resonance islands in (generalized) mushroom billiards, which are a recently discovered class of Hamiltonian systems with mixed regular-chaotic dynamics. In the few-particle case, we compare the dynamics in container geometries whose counterpart one-particle billiards are integrable, chaotic, and mixed. One of our findings is that two-, three-, and four-particle billiards confined to containers with integrable one-particle counterparts inherit some integrals of motion and exhibit a regular partition of phase space into ergodic components of positive measure. Therefore, the shape of a container matters not only for noninteracting particles but also for interacting particles.

The exploration of fundamental quantum phenomena, such as entanglement and Bell inequality violations$-$extensively studied in low-energy regimes$-$has recently extended to high-energy particle collisions. Experimentally, Bell inequality violations, which challenge Einstein's principle of local realism, were first observed in low-energy entangled photon systems by A. Aspect, J. F. Clauser, and A. Zeilinger, earning them the 2022 Nobel Prize in Physics. Particle colliders provide a novel setting for probing quantum information theory, operating at energies over ten orders of magnitude higher than previous experiments and in the presence of electroweak and strong interactions. Additionally, collider detectors offer unique advantages for quantum state reconstruction via quantum state tomography. This book chapter reviews key theoretical and experimental advancements in this emerging field, highlighting its challenges, objectives, and potential impact on both quantum information theory and high-energy physics.

Discovery of the J Particle at Brookhaven National Laboratory and the Physics of Electrons and Positrons; The Standard Model Yesterday, Today and Tomorrow; The Rise of Gauge Theories: From Many Models to One Theory; From Charm to CP Violation; When the Standard Model Was Ignored; The Discovery of the W and Z Bosons at the CERN Proton-Antiproton Collider; A Personal History of CERN Particle Colliders (1972-2022); The Age of Gravitational Wave Astronomy; Precision Physics in the Era of (HL)LHC; Recent Developments in Flavor Physics, the Unitary Triangle Fit, Anomalies and All That; About BSM Physics, with Emphasis on Flavour; The Discovery of the Antiproton between Rome and Berkeley; Raoul Gatto and Bruno Touschek: the Rise of $e+e^-$ Physics; From ADONE's Multi-Hadron Production to the J/$Ψ$ Discovery; From Bjorken Scaling to Scaling Violations

This paper presents novel approaches to parallelizing particle interactions on a GPU when there are few particles per cell and the interactions are limited by a cutoff distance. The paper surveys classical algorithms and then introduces two alternatives that aim to utilize shared memory. The first approach copies the particles of a sub-box, while the second approach loads particles in a pencil along the X-axis. The different implementations are compared on three GPU models using Cuda and Hip. The results show that the X-pencil approach can provide a significant speedup but only in very specific cases.

Functional methods like Dyson-Schwinger equations, the $n$PI effective action formalism, bound state equations and the functional renormalization group are versatile tools to study quantum field theories. They are exact, nonperturbative equations but have to be truncated for practical calculations. After a general introduction, I focus on their use in particle physics and discuss common truncations and solution techniques. The complete process from choosing a truncation to calculating observable quantities is exemplified by means of the glueball spectrum.

This paper proposes regenerative particle Thompson sampling (RPTS), a flexible variation of Thompson sampling. Thompson sampling itself is a Bayesian heuristic for solving stochastic bandit problems, but it is hard to implement in practice due to the intractability of maintaining a continuous posterior distribution. Particle Thompson sampling (PTS) is an approximation of Thompson sampling obtained by simply replacing the continuous distribution by a discrete distribution supported at a set of weighted static particles. We observe that in PTS, the weights of all but a few fit particles converge to zero. RPTS is based on the heuristic: delete the decaying unfit particles and regenerate new particles in the vicinity of fit surviving particles. Empirical evidence shows uniform improvement from PTS to RPTS and flexibility and efficacy of RPTS across a set of representative bandit problems, including an application to 5G network slicing.

Computing on graphics processing units (GPUs) has become standard in scientific computing, allowing for incredible performance gains over classical CPUs for many computational methods. As GPUs were originally designed for 3D rendering, they still have several features for that purpose that are not used in scientific computing. Among them, ray tracing is a powerful technology used to render 3D scenes. In this paper, we propose exploiting ray tracing technology to compute particle interactions with a cutoff distance in a 3D environment. We describe algorithmic tricks and geometric patterns to find the interaction lists for each particle. This approach allows us to compute interactions with quasi-linear complexity in the number of particles without building a grid of cells or an explicit kd-tree. We compare the performance of our approach with a classical approach based on a grid of cells and show that, currently, ours is slower in most cases but could pave the way for future methods.

Particle tracking is a key to single-particle-level confocal microscopy observation of colloidal suspensions, emulsions, and granular matter. The conventional tracking method has not been able to provide accurate information on the size of individual particle. Here we propose a novel method to localise spherical particles of arbitrary relative sizes from either 2D or 3D (confocal) images either in dilute or crowded environment. Moreover this method allows us to estimate the size of each particle reliably. We use this method to analyse local bond orientational ordering in a supercooled polydisperse colloidal suspension as well as the heterogeneous crystallisation induced by a substrate. For the former, we reveal non-trivial couplings of crystal-like bond orientational order and local icosahedral order with the spatial distribution of particle sizes: Crystal-like order tends to form in regions where very small particles are depleted and the slightly smaller size of the central particle stabilizes icosahedral order. For the latter, on the other hand, we found that very small particles are expelled from crystals and accumulated on the growth front of crystals. We emphasize that such in

Charged particle beams that remain stationary while passing through a transport channel are represented by ``self-consistent'' phase space distributions. As the starting point, we assume the external focusing forces to act continuously on the beam. If Liouville's theorem applies, an infinite variety of self-consistent particle phase space distributions exists then. The method is reviewed how to determine the Hamiltonian of the focusing system for a given phase space density function. Subsequently, this Hamiltonian is transformed canonically to yield the appropriate Hamiltonian that pertains to a beam passing through a non-continuous transport system. It is shown that the total transverse beam energy is a conserved quantity, if the beam stays rotationally symmetric along the channel. It can be concluded that charged particle beams can be transmitted through periodic solenoid channels without loss of quality. Our computer simulations, presented in the second part of the paper, confirm this result. In contrast, the simulation for a periodic quadrupole channel yields a small but constant growth rate of the rms-emittance.

Solid particles in protoplanetary disks that are sufficiently super-solar in metallicity overcome turbulence generated by vertical shear to gravitationally condense into planetesimals. Super-solar metallicities result if solid particles pile up as they migrate starward as a result of aerodynamic drag. Previous analyses of aerodynamic drift rates that account for mean flow differences between gas and particles yield particle pile-ups. We improve on these studies not only by accounting for the collective inertia of solids relative to that of gas, but also by including the transport of angular momentum by turbulent stresses within the particle layer. These turbulent stresses are derived in a physically self-consistent manner from the structure of marginally Kelvin-Helmholtz turbulent flows. They are not calculated using the usual plate drag formulae, whose use we explain is inappropriate. Accounting for the relative inertia of solids to gas retards, but does not prevent, particle pile-ups, and generates more spatially extended regions of metal enrichment. Turbulent transport hastens pile-ups. We conclude that particle pile-up is a robust outcome in sufficiently passive protoplanetary

Gravitational waves (GWs) were recently detected for the first time. This revolutionary discovery opens a new way of learning about particle physics through GWs from first-order phase transitions (FOPTs) in the early Universe. FOPTs could occur when new fundamental symmetries are spontaneously broken down to the Standard Model and are a vital ingredient in solutions of the matter anti-matter asymmetry problem. The purpose of our work is to review the path from a particle physics model to GWs, which contains many specialized parts, so here we provide a timely review of all the required steps, including: (i) building a finite-temperature effective potential in a particle physics model and checking for FOPTs; (ii) computing transition rates; (iii) analyzing the dynamics of bubbles of true vacuum expanding in a thermal plasma; (iv) characterizing a transition using thermal parameters; and, finally, (v) making predictions for GW spectra using the latest simulations and theoretical results and considering the detectability of predicted spectra at future GW detectors. For each step we emphasize the subtleties, advantages and drawbacks of different methods, discuss open questions and revie

Radiation appearing when relativistic charged particles moves along a periodic structure without external fields is investigated. It is shown that nonsynchronous spatial harmonics of wakefields excited by bunched charged particles can give rise to the particle oscillatory motion that consequently generates the undulator-type radiation (UR). A theory of the undulator-type radiation emitted by ultrarelativistic charged particles in the self-wakefields is given. An analytical expression for the spontaneous UR power of the ultrarelativistic monochromatic charged bunch moving in a weakly corrugated axially-symmetrical waveguide is derived by the perturbation method. The parameter region, a particle number and particle energies at which the spontaneous UR power exceeds the wakefield power is analyzed.

Bose-Einstein correlations of identical bosons reveal information about the space-time structure of particle emission from the sQGP formed in ultra-relativistic heavy-ion collisions. Previous measurements of two particle correlations have shown that the source can best be described by a symmetric Levy distribution. Here we report on the measurement of three-particle correlations in 0-30 % centrality Au+Au collisions at $\sqrt{s_{_\text{NN}}} = 200$ GeV, and describe them with a Levy type source. This measurement may shed light on hadron creation mechanisms beyond chaotic emission. We measure three particle correlation strength ($λ_3$) as a function of pair transverse momentum. This parameter, combined with two-particle correlation strength $λ_2$ may reveal the level of chaoticity and coherence in particle production.

Experimental tests of the Standard Model of particle physics (SM) find excellent agreement with its predictions. Since the original formation of the SM, experiments have provided little guidance regarding the explanations of phenomena outside the SM, such as the baryon asymmetry and dark matter. Nor have we understood the aesthetic and theoretical problems of the SM, despite years of searching for physics beyond the Standard Model (BSM) at particle colliders. Some BSM particles can be produced at colliders yet evade being discovered, if the reconstruction and analysis procedures not matched to characteristics of the particle. An example is particles with large lifetimes. As interest in searches for such long-lived particles (LLPs) grows rapidly, a review of the topic is presented in this article. The broad range of theoretical motivations for LLPs and the experimental strategies and methods employed to search for them are described. Results from decades of LLP searches are reviewed, as are opportunities for the next generation of searches at both existing and future experiments.

Shear flows are ubiquitously present in space and astrophysical plasmas. This paper highlights the central idea of the non-thermal acceleration of charged particles in shearing flows and reviews some of the recent developments. Topics include the acceleration of charged particles by microscopic instabilities in collisionless relativistic shear flows, Fermi-type particle acceleration in macroscopic, gradual and non-gradual shear flows, as well as shear particle acceleration by large-scale velocity turbulence. When put in the context of jetted astrophysical sources such as Active Galactic Nuclei, the results illustrate a variety of means beyond conventional diffusive shock acceleration by which power-law like particle distributions might be generated. This suggests that relativistic shear flows can account for efficient in-situ acceleration of energetic electrons and be of relevance for the production of extreme cosmic rays.

Charged lepton flavor violation is an unambiguous signature for New Physics. Here we present a summary of the theoretical and experimental status of the search for charged lepton flavor violation in heavy particle decays, in particular in the decays of the Z and Higgs bosons, and of the top quark. Decays of beyond-Standard-Model particles such as a Z' or an additional scalar particle are also discussed. Finally the prospects for such searches at proposed future electron-positron colliders are reviewed.

In nuclear, particle and astroparticle physics experiments, calorimeters are used to measure the properties of particles with kinetic energies that range from a fraction of 1 eV to 10^20 eV or more. These properties are not necessarily limited to the energy carried by these particles, but may concern the entire four-vector, including the particle mass and type. In many modern experiments, large calorimeter systems play a central role, and this is expected to be no different for experiments that are currently being planned/designed for future accelerators. In this paper, the state of the art as well as new developments in calorimetry are reviewed. The latter are of course inspired by the perceived demands of future experiments, and/or the increasing demands of the current generation of experiments, as these are confronted with, for example, increased luminosity. These demands depend on the particles to be detected by the calorimeter. In electromagnetic calorimeters, radiation hardness of the detector components is a major concern. The generally poor performance of the current generation of hadron calorimeters is considered inadequate for future experiments, and a lot of the R&D