Search

We solve the particle-antiparticle and cosmological constant problems proceeding from quantum theory, which postulates that: various states of the system under consideration are elements of a Hilbert space H with a positive definite metric; each physical quantity is defined by a self-adjoint operator in H ; symmetry at the quantum level is defined by a representation of a real Lie algebra A in H such that the representation operator of any basis element of A is self-adjoint. These conditions guarantee the probabilistic interpretation of quantum theory. We explain that in the approaches to solving these problems that are described in the literature, not all of these conditions have been met. We argue that fundamental objects in particle theory are not elementary particles and antiparticles but objects described by irreducible representations (IRs) of the de Sitter (dS) algebra. One might ask why, then, experimental data give the impression that particles and antiparticles are fundamental and there are conserved additive quantum numbers (electric charge, baryon quantum number and others). The reason is that, at the present stage of the universe, the contraction parameter R from the dS to the Poincare algebra is very large and, in the formal limit R → ∞ , one IR of the dS algebra splits into two IRs of the Poincare algebra corresponding to a particle and its antiparticle with the same masses. The problem of why the quantities (c , ℏ , R) are as are does not arise because they are contraction parameters for transitions from more general Lie algebras to less general ones. Then the baryon asymmetry of the universe problem does not arise. At the present stage of the universe, the phenomenon of cosmological acceleration (PCA) is described without uncertainties as an inevitable kinematical consequence of quantum theory in semiclassical approximation. In particular, it is not necessary to involve dark energy the physical meaning of which is a mystery. In our approach, background space and its geometry are not used and R has nothing to do with the radius of dS space. In semiclassical approximation, the results for the PCA are the same as in General Relativity if Λ = 3 / R 2 , i.e., Λ > 0 and there is no freedom for choosing the value of Λ. [ABSTRACT FROM AUTHOR]

This international curricular review provides a structured overview of the particle physics content in 27 state, national, and international high-school physics curricula. The review was based on a coding manual that included 60 concepts that were identified as relevant for high-school particle physics education. Two types of curricula were reviewed, namely curricula with a dedicated particle physics chapter and curricula without a dedicated particle physics chapter. The results of the curricular review show that particle physics concepts are explicitly or implicitly present in all reviewed curricula. However, the number of particle physics concepts that are featured in a curriculum varies greatly across the reviewed curricula. We identified core particle physics concepts that can be found in most curricula. Here, elementary particles, fundamental interactions, and charges were identified as explicit particle physics concepts that are featured in more than half of the reviewed curricula either as content or context. Indeed, theoretical particle physics concepts are more prominent in high-school physics curricula than experimental particle physics concepts. Overall, this international curricular review provides the basis for future curricular development with respect to particle physics and suggests an increased inclusion of experimental particle physics concepts in high-school physics curricula. [ABSTRACT FROM AUTHOR]

By 1933, the class of generally accepted elementary particles comprised the electron, the photon, the proton as well as newcomers in the shape of the neutron, the positron, and the neutrino. During the following decade, a new and poorly understood particle, the mesotron or meson, was added to the list. By paying close attention to the names of these and other particles and to the sometimes controversial proposals of names, a novel perspective on this well-researched line of development is offered. Part of the study investigates the circumstances around the coining of "positron" as an alternative to "positive electron." Another and central part is concerned with the many names associated with the discovery of what in the late 1930s was generally called the "mesotron" but eventually became known as the "meson" and later again the muon and pion. The naming of particles in the period up to the early 1950s was more than just a matter of agreeing on convenient terms, it also reflected different conceptions of the particles and in some cases the uncertainty regarding their nature and relations to existing theories. Was the particle discovered in the cosmic rays the same as the one responsible for the nuclear forces? While two different names might just be synonymous referents, they might also refer to widely different conceptual images. [ABSTRACT FROM AUTHOR]

Peter Higgs was a British theoretical physicist, renowned for his 1964 work in which he proposed a mechanism capable of generating masses for elementary particles while conforming to gauge symmetry. Half a century later, two experiments at CERN confirmed that this mechanism is realized in nature. On April 8th, we received the sad news of the passing of this great pioneer in elementary particle physics. This article is dedicated to his memory, and to the mechanism and particle that bear his name. [ABSTRACT FROM AUTHOR]

The mystery associated with a proposed Dark Sector of phenomena that are separate from the standard model of particle physics is described. A Dark Sector may possess matter particles, force carriers which mediate their interactions, and new interactions and symmetries that are beyond the standard model of particle physics. Various approaches for Dark Sector searches are described, including those at the energy frontier at the Large Hadron Collider, in astrophysical interactions with both terrestrial experiments and those in space-born platforms. Searches using low energy photons from microwave energies in cryogenic environments to x-ray energies are also described. While there is no noncontroversial evidence for Dark Sector phenomena presently, new searches with more modern equipment and analysis methods are exploring regions of phase space that have not been available before now, indicating ongoing interest and excitement in this research. [ABSTRACT FROM AUTHOR]

The fragmentation of quasi-projectiles from the nuclear reaction 40 Ca+ 12 C at 25 MeV per nucleon bombarding energy was used to produce excited self-conjugate nuclei (from 16 O to 28 Si). Temperature and density conditions for alpha-clustering were determined. Measured temperatures have been found in the range of 5.5 - 6.0 MeV whereas density values of 0.3 - 0.4 times the saturation density are deduced. This density domain is also predicted by constrained self-consistent mean field calculations. At present such calculations are performed at zero temperatures and geometric alpha cluster configurations are observed: a tetrahedron for 16 O for example. Experimentally, by looking to 8 Be production from excited self-conjugate nuclei, a signature of final state interaction between two alpha-particles was evidenced. This indicates that, due to the temperature, geometric configurations are not the only ones present, which argues in favor of finite temperature calculations. [ABSTRACT FROM AUTHOR]

Chirality is a phenomenon with widespread relevance in fundamental physics, material science, chemistry, optics, and spectroscopy. In this work, we show that a free electron can be converted by the field cycles of laser light into a right-handed or left-handed coil of mass and charge. In contrast to phase-vortex beams, our electrons maintained a flat de Broglie wave but obtained their chirality from the shape of their expectation value in space and time. Measurements of wave function densities by attosecond gating revealed the three-dimensional shape of coils and double coils with left-handed or right-handed pitch. Engineered elementary particles with such or related chiral geometries should be useful for applications in chiral sensing, free-electron quantum optics, particle physics or electron microscopy. [ABSTRACT FROM AUTHOR]

Critical advances in radionuclide therapy have led to encouraging new options for cancer treatment through the pairing of clinically useful radiation-emitting radionuclides and innovative pharmaceutical discovery. Of the various subatomic particles used in therapeutic radiopharmaceuticals, alpha (α) particles show great promise owing to their relatively large size, delivered energy, finite pathlength, and resulting ionization density. This review discusses the therapeutic benefits of α-emitting radiopharmaceuticals and their pairing with appropriate diagnostics, resulting in innovative "theranostic" platforms. Herein, the current landscape of α particle-emitting radionuclides is described with an emphasis on their use in theranostic development for cancer treatment. Commonly studied radionuclides are introduced and recent efforts towards their production for research and clinical use are described. The growing popularity of these radionuclides is explained through summarizing the biological effects of α radiation on cancer cells, which include DNA damage, activation of discrete cell death programs, and downstream immune responses. Examples of efficient α-theranostic design are described with an emphasis on strategies that lead to cellular internalization and the targeting of proteins involved in therapeutic resistance. Historical barriers to the clinical deployment of α-theranostic radiopharmaceuticals are also discussed. Recent progress towards addressing these challenges is presented along with examples of incorporating α-particle therapy in pharmaceutical platforms that can be easily converted into diagnostic counterparts. [ABSTRACT FROM AUTHOR]

The model analysis of particle production in heavy ion collisions depending on number of emission sources (wounded nucleons or partons) at different centralities is performed in a wide collision energy range from RHIC to LHC. The model of wounded partons based on Glauber calculations gives better scaling for the ratio of charged particle multiplicity to the number of wounded constituent partons depending on collision centrality for all considered energies and colliding systems. Also, the eccentricity density distribution in Glauber Monte Carlo framework has been fulfilled for several centrality intervals. Assuming linear dependence between eccentricity and elliptic flow, the eccentricity density distribution is compared with CMS data on flow fluctuations for PbPb collisions at TeV data. For centralities less than 35 the probability density distribution with wounded partons better describes experimental data. For more peripheral collisions () both models describe data satisfactorily. [ABSTRACT FROM AUTHOR]

The article is a review of the book "Particle Therapy Technology for Safe Treatment" edited by Jay Flanz. The book provides a comprehensive overview of particle therapy technology, explaining key parameters and physics concepts. It emphasizes the importance of safety in clinical implementation and offers practical examples and exercises to reinforce learning. The book covers topics such as particle physics, treatment planning, dosimetry, and the importance of a culture of safety. It is recommended for readers with a background in radiation physics, as well as radiation therapists and biomedical engineers. [Extracted from the article]

We consider an extension of the Standard Model of particle physics with an additional SU(2) gauge sector along with an additional scalar bidoublet and a non-linear sigma field. The neutral components of the bidoublet serve as dark matter candidates by virtue of the bidoublet being odd under a Z 2 symmetry. Generic beyond Standard Model constraints like vacuum stability, invisible decay of Higgs, Higgs alignment limit and collider constraints on heavy gauge bosons restrict the parameter space of this model. In this multicomponent dark matter scenario, we investigate the interplay between the annihilation and co-annihilation channels originating from the new gauge sector as those contribute to the relic abundance. We also inspect the direct detection constraints on scattering cross-sections of the dark matter particles with the detector nucleons and present our observations. [ABSTRACT FROM AUTHOR]

Production of inclusive charmonia in pp collisions at center-of-mass energy of s = 13 TeV and p–Pb collisions at center-of-mass energy per nucleon pair of s NN = 8.16 TeV is studied as a function of charged-particle pseudorapidity density with ALICE. Ground and excited charmonium states (J/ψ, ψ(2S)) are measured from their dimuon decays in the interval of rapidity in the center-of-mass frame 2.5 < ycms< 4.0 for pp collisions, and 2.03 < ycms< 3.53 and −4.46 < ycms< −2.96 for p–Pb collisions. The charged-particle pseudorapidity density is measured around midrapidity (|η| < 1.0). In pp collisions, the measured charged-particle multiplicity extends to about six times the average value, while in p-Pb collisions at forward (backward) rapidity a multiplicity corresponding to about three (four) times the average is reached. The ψ(2S) yield increases with the charged-particle pseudorapidity density. The ratio of ψ(2S) over J/ψ yield does not show a significant multiplicity dependence in either colliding system, suggesting a similar behavior of J/ψ and ψ(2S) yields with respect to charged-particle pseudorapidity density. Results for the ψ(2S) yield and its ratio with respect to J/ψ agree with available model calculations. [ABSTRACT FROM AUTHOR]

This article presents a short review of a geometric approach to the theory of elementary particles which was proposed early. The wave function of particle, instead of the spinor representation, is given by the Clifford number, whose transfer rules have the structure of the Dirac equation for any manifold. The solution to this equation is obtained in terms of geometric characteristics. New experiments are proposed to show the geometric nature of the wave function of an elementary particle. [ABSTRACT FROM AUTHOR]

The IPAC20 story began in February 2015 when the Grand Accélérateur National d'Ions Lourds (GANIL) in Caen, France decided for the second time to bid to host the prestigious International Particle Accelerator Conference (IPAC) conference, bringing together 1,300 members of the particle accelerator community. Novikov I NRC Kurchatov Institute-PNPI i Graph V. I. Zherebchevsky I St. Petersburg State University i Humanity and Physics Meet at Tenth Tastes of Nuclear Physics For the last 10 years, the Tastes of Nuclear Physics has served as one of South Africa's most successful conferences on fundamental nuclear physics and applications. The main goals are enthusing South African students toward their highest education and physics achievements by attracting world-class speakers to instruct them on timely topics in nuclear physics and nuclear astrophysics. [Extracted from the article]

An approach for particle breakage simulation based on the framework of discrete element method was proposed in the current study. Convex polyhedron blocks were adopted as elementary particles for the complex particle shapes, and the variability of particle breakage strength is modeled using the invertible function method. Additionally, the traditional modified "Brazilian" criterion was adopted as the breakage criterion. Under the assumption that the eventual fractures within a particle can be determined according to the contact points and the centroid of the particle, once a target particle fulfilled the breakage criterion, it was cut into several fragments by a series of virtual cutting faces, which are consistent with the eventual fractures. With this, the production of local stress and the non-conservation of mass and volume can be avoided. A pre-defined fragmentation mode was also unnecessary for this approach. A series of numerical triaxial tests adopting this new presented approach was then conducted according to the configurations reported in the literature and comparisons made with experimental results. It revealed that while the presented approach is capable of reproducing the macroscopic shear responses and particle breakage characteristics of breakable particle assemblies, some fragmentation modes of particles such as surface grinding and corner abrasion cannot be captured using this approach, presenting an area for future investigation. [ABSTRACT FROM AUTHOR]

Particle/cell separation from a mixture using a hydrodynamic vortex has been attracting much interest for the isolation of circulating tumor cells in basic biological studies and clinical applications. However, some issues regarding the particle recirculating orbits within the vortex in microcavities remain unclear. In this work, using micro-particle image velocimetry and a high-speed microscopy system, we quantitatively investigate the effects of inlet Reynolds numbers (Re) on the microcavity flow characteristics and particle recirculating behavior. The results show that due to the evolution of microcavity flow patterns (Re = 15–313), the particle orbit topology expands gradually, developing from a single small orbit (Re = 39–79) to a single semicircular orbit (98–117), then to alternating double orbits (Re = 136–215), and at last to a single large orbit (Re = 254–352). The alternating double orbits are observed for the first time. The particle orbit periods and topologies (lengths and area) have also been characterized. Moreover, the variations of the recirculating particle velocity are also quantitatively measured. The results deepen the fundamental understanding of particle recirculating behavior and could provide useful guidance for vortex-based microfluidics. [ABSTRACT FROM AUTHOR]

Abstract Following first large-scale applications in highly granular calorimeters and in neutrino detectors, Silicon Photomultipliers have seen a wide adoption in accelerator-based particle and nuclear physics experiments. Today, they are used for a wide range of different particle detector types, ranging from calorimeters and trackers to particle identification and veto detectors, large volume detectors for neutrino physics and timing systems. This article reviews the current state and expected evolution of these applications, highlighting strengths and limitation of SiPMs and the corresponding design choices in the respective contexts. General trends and adopted technical solutions in the applications are discussed. [ABSTRACT FROM AUTHOR]

In recent decades, γ -ray spectroscopy has undergone a major technological leap forward, namely the technique of γ -ray tracking, and has attained a sensitivity that is two orders of magnitude larger than that provided by the former generation of Compton-shielded arrays. Indeed the gain is comparable with the achievements since the dawn of γ -ray spectroscopy. Such sensitivity can be further heightened by coupling γ -ray spectrometers to other detectors that record complementary reaction products such as light-charged particles for transfer reactions and scattered ions for Coulomb excitation measurements. Nucleon transfer reactions offer an excellent mean to probe the energies of shell model single-particle orbitals and to study migration in energy of these orbitals as we venture away from stability. Such measurements can also estimate the cross sections of processes relevant to stellar evolution and nucleosynthesis. The measurement of γ rays in coincidence with particles provides also information on the decay channel for unbound systems, which constitutes a useful input for astrophysics and nuclear structure near the drip-lines. Coulomb-excitation studies make it possible to infer collective structure in nuclei and to extract deformation properties of, in particular, open-shell systems. Here, selected examples will be presented, highlighting the power of these types of experiments when γ -ray observation is included. The development of the experimental methods is reviewed, showing the results achieved before the advent of γ -ray tracking. Examples of more recent experiments that have successfully exploited γ -ray tracking with AGATA are then presented as showcases for the outstanding performance of the composite detection systems. The outlook for experiments using newly developed devices such as GRIT and other detectors such as SPIDER is described. [ABSTRACT FROM AUTHOR]

In our earlier work, we suggested an axiomatic framework for deducing the fundamental entities which constitute the building block of the elementary particles in physics. The basic concept of this theory, named apriorics, is the ontological structure (OS)—an undirected simple graph satisfying specified conditions. The vertices of this graph represent the fundamental entities (FEs), its edges are binary compounds of the FEs (which are the fundamental bosons and fermions), and the structures constituting more than two connected vertices are composite particles. The objective of this paper is to focus the attention on several mathematical theorems and ideas associated with such graphs of order n, including their enumeration, showing what is the information content of apriorics. [ABSTRACT FROM AUTHOR]

Neutrino physics is one of the most important topics in particle physics and cosmology. As it is known, neutrinos are weakly interacting fundamental particles with chargeless and very small masses. One of the most characteristic features of the neutrino that make a difference from other elementary particles is that it oscillates between the mass and flavour eigenstates. Due to these oscillations, neutrinos change from one flavour to another. So far in theory the possible effects of deformed space-time effects on oscillation have not been considered. In this study, we show for the first time that a deformed space-time metric will lead to fractional dynamics between mass and flavour changes and therefore cause a phase shift in the oscillation period. We also shortly discuss the possible relation between anomalous cyclic and relic neutrinos. The modification in the oscillation probabilities due to the studied effect in this work could be seen using relic neutrinos. [ABSTRACT FROM AUTHOR]

The status of the study of multiple fragmentation of 950 MeV per nucleon Kr nuclei in a nuclear track emulsion aimed at determining the contributions of 2 decays of Be, the Hoyle 3 state, and the search for a 4 particle condensate state, is presented. In events with the production of few relativistic fragments of He and H, the possibility of estimating the multiplicity of neutrons in the fragmentation cone of a projectile nucleus is studied. For the planar component of neutron transverse momenta estimated from the angles of observed secondary stars, the Rayleigh distribution parameter was MeV/c. The importance of such events for the interpretation of cosmophysical observations is noted. [ABSTRACT FROM AUTHOR]

During acceleration of particles with a charge-to-mass ratio of 1 : 2, the length of a cavity is practically doubled compared to that of a proton accelerator for the same energy. At an output energy exceeding 1.0 MeV per nucleon, the cavity length becomes large, Lcav ≈ 3λ, where λ is the wavelength of the TE211 operating mode. This leads to a critically small frequency separation between the operating TE211 quadrupole mode and the TE11n dipole modes. For mode separation, it is proposed to use coupling windows in the electrodes between neighboring structure segments, which in turn change the field distribution along the structure. Field uniformity is restored with the insertion of plungers into the four segments between the electrodes through the RFQ shell. The result of the simulation is a tuned RFQ accelerating structure with the following main parameters: the ion type is deuterons D+ or alpha particle He++, the operating frequency is 202 MHz, the injection voltage is 75 kV, the length is 4.3 m, the peak RF power is not higher than 300 kW, the energy of accelerated ions is 1.25 MeV/nucleon, and the peak current is 50 mA for D+ and 10 mA for He++. The result is the design of the RFQ structure based on the performed electrodynamics and beam dynamics simulation. [ABSTRACT FROM AUTHOR]

Radiophotoluminescence of F 2 and F 3 + color centers in LiF was exploited for imaging tracks of energetic heavy charged particles. LiF crystals were irradiated with helium, carbon, neon, silicon and iron ions at the HIMAC accelerator in Chiba, Japan. The patterns created by radiation were visualized with a wide-field fluorescent microscope under blue-light excitation. The shape of the visible tracks was found not to depend on ion type and energy. The full width at half maximum of track profiles was in all cases around 500 nm, what corresponds with the resolution limit of the microscope, which was estimated to be 420 nm. On the other hand the fluorescent intensity of tracks was found to increase in a linear manner with the increasing LET. This indicates possibility of obtaining some spectrometric information on the radiation field. • Tracks of nuclear particles visualized through fluorescence of color centers in LiF. • Tracks of He, C, Ne, Si and Fe ions obtained. • Track intensity grows linearly with increasing ionization density. [ABSTRACT FROM AUTHOR]

For decades, in diffusion cloud chambers, different types of subatomic particle tracks from radioactive sources or cosmic radiation had to be identified with the naked eye which limited the amount of data that could be processed. In order to allow these classical particle detectors to enter the digital era, we successfully developed a neuro-explicit artificial intelligence model that, given an image from the cloud chamber, automatically annotates most of the particle tracks visible in the image according to the type of particle or process that created it. To achieve this goal, we combined the attention U-Net neural network architecture with methods that model the shape of the detected particle tracks. Our experiments show that the model effectively detects particle tracks and that the neuro-explicit approach decreases the misclassification rate of rare particles by 73% compared with solely using the attention U-Net. [ABSTRACT FROM AUTHOR]

Primary simulations of neutron interactions are performed on Si1−xGex alloys with a Monte Carlo (MC) code using the binary collision approximation (BCA). Then, a statistical study of the collision cascades development in Si0.8Ge0.2, Si0.7Ge0.3, and Si0.5Ge0.5 is carried out using molecular dynamics (MD), starting from both Si and Ge primary knock-on atoms (PKAs) of 1, 5, and 10 keV. The well-known Stillinger–Weber (SW) MD potential, which can be used to study Si, Ge, and Si1−xGex, is coupled to the Ziegler–Biersack–Littmark (ZBL) universal potential to better describe the collisions between atoms. To account for the stopping power of the electrons, the two-temperature model (TTM) is combined with MD. Similar studies are performed on pure Si and pure Ge in order to be able to compare our Si–Ge alloys damaged structures with reference materials. Moreover, data obtained by TTM-MD on Si, Ge, and Si1−xGex are compared with collision cascades statistical data from MC codes. [ABSTRACT FROM AUTHOR]

Purpose: As for vibrating screen, the separation of granular materials is a very complicated process, particularly the screening with a swing trace. To study the characteristics of stratification and penetration in the swing vibrating screen, a three-dimensional numerical model was developed to simulate the screening process. Design/methodology/approach: The discrete element method (DEM) was used to perform the numerical simulation, and the kinetic model of the swing screening was established. The regions of stratification and penetration were defined, and the mathematical functions relating fine particle ratio of stratification and penetration to time were presented using the least squares method. Findings: The results show that the low value of frequency (5 and 10 Hz) has a limited effect on the stratification, while the obvious effect can be found at high frequency. A low frequencies or small swing angles may enhance the particle penetration. By studying the vibration parameters affecting the stratification and penetration rate, it is found that the frequency has more influence than the swing angle. Originality/value: The higher screening efficiency and processing capacity can be further obtained for the swing vibrating screen by comparing with the linear vibrating screen. These results reveal the fundamental characteristics of particle motion in the swing screening, which will provide reliable guidance for studying the design optimization of vibrating screen. [ABSTRACT FROM AUTHOR]

The 12C(p,2p)11B reaction at E p =98.7 MeV proton beam energy is analyzed using a rigorous three-particle scattering formalism extended to include the internal excitation of the nuclear core or residual nucleus. The excitation proceeds via the core interaction with any of the external nucleons. We assume the 11B ground and low-lying excited states [ 3 2 − (0.0 MeV), 5 2 − (4.45 MeV), 7 2 − (6.74 MeV)] and the excited states [ 1 2 − (2.12 MeV), 3 2 − (5.02 MeV)] to be members of K = 3 2 − and K = 1 2 − rotational bands, respectively. The dynamical core excitation results in a significant cross section for the reaction leading to the 5 2 − (4.45 MeV) excited state of 11B that cannot be populated through the single-particle excitation mechanism. The detailed agreement between the theoretical calculations and data depends on the used optical model parametrizations and the kinematical configuration of the detected nucleons. [ABSTRACT FROM AUTHOR]

Neutrino physics is one of the most important topics in particle physics and cosmology. As it is known, neutrinos are weakly interacting fundamental particles with chargeless and very small masses. One of the most characteristic features of the neutrino that make a difference from other elementary particles is that it oscillates between the mass and flavour eigenstates. Due to these oscillations, neutrinos change from one flavour to another. So far in theory the possible effects of deformed space-time effects on oscillation have not been considered. In this study, we show for the first time that a deformed space-time metric will lead to fractional dynamics between mass and flavour changes and therefore cause a phase shift in the oscillation period. We also shortly discuss the possible relation between anomalous cyclic and relic neutrinos. The modification in the oscillation probabilities due to the studied effect in this work could be seen using relic neutrinos. [ABSTRACT FROM AUTHOR]

The study of the particle movement in cyclone has been expanded from revolution to high-speed self-rotation, and produced a series of new technologies and new applications. However, the spatial rules and regulation methods of particle high-speed self-rotation in cyclones are yet to be studied. In this study, four kinds of inlet particle pre-self-rotation cyclones were designed, and the effect of the pre-self-rotation on the flow field as well as the particle revolution and high-speed self-rotation were studied. It was observed that adding the particle pre-rotator had a significant effect on the particle revolution and self-rotation in cyclones. Parallel positive rotation cyclone (PPR-C) exhibited the best performance as the particle self-rotation speed reached up to 10,851 rad/s, which was 1.89 times that in common cyclone (CM-C). This study can provide theoretical fundamental for the regulation of particle self-rotation in cyclones and pollutant cyclone separation enhancement by particle high-speed self-rotation [Display omitted] • Four kinds of inlet pre-self-rotation cyclones were designed for self-rotation enhancement. • The effect of different pre-self-rotation types on the flow field was obtained. • The effect of different pre-self-rotation types on the particle self-rotation was obtained. • The effect of different pre-self-rotation types on the particle revolution was obtained. • An effective method for enhancing the high-speed rotation of particles in cyclone was obtained. [ABSTRACT FROM AUTHOR]

The second-order (v2) and third-order (v3) Fourier coefficients describing the azimuthal anisotropy of prompt and nonprompt (from b-hadron decays) J/ψ, as well as prompt ψ(2S) mesons are measured in lead-lead collisions at a center-of-mass energy per nucleon pair of s NN = 5.02 TeV. The analysis uses a data set corresponding to an integrated luminosity of 1.61 nb−1 recorded with the CMS detector. The J/ψ and ψ(2S) mesons are reconstructed using their dimuon decay channel. The v2 and v3 coefficients are extracted using the scalar product method and studied as functions of meson transverse momentum and collision centrality. The measured v2 values for prompt J/ψ mesons are found to be larger than those for nonprompt J/ψ mesons. The prompt J/ψ v2 values at high pT are found to be underpredicted by a model incorporating only parton energy loss effects in a quark-gluon plasma medium. Prompt and nonprompt J/ψ meson v3 and prompt ψ(2S) v2 and v3 values are also reported for the first time, providing new information about heavy quark interactions in the hot and dense medium created in heavy ion collisions. [ABSTRACT FROM AUTHOR]

Abstract In this work we have developed a prototype gaseous pixel detector by combining a micromegas grid with a Timepix3 chip for the readout. The micromegas foil supported by a matrix of pillars about 50 μ m high was manually placed on top the chip. By placing a cathode foil above the chip an ionisation detector was created with a drift gap of 13.5 m m. The Timepix3 chip, thanks to the simultaneous measurement of the time-of-arrival (ToA) and charge via time-over-threshold (ToT) allows corrections to remaining timewalk effects, improving further the position resolution along the drift direction. We present the timewalk correction for Timepix3 chip obtained with real data from a particle beam and its impact on the tracking performance. The results obtained show a significant improvement on the position resolution for single-hits and tracks along the drift direction compared to previous experiments. [ABSTRACT FROM AUTHOR]

The intrinsic reaction mechanism of proton-induced composite particle pre-equilibrium emission is well known to be a statistical multistep process. However, until recently it was still not clear how important the competition between pickup and knockout is to produce a composite ejectile in the multistep sequence. An evaluation of recent (p , α) results at incident energies from 65 to 160 MeV and on representative target nuclei is presented. The virtue of analyzing power angular distributions to unravel the details of the reaction mechanism is discussed and future possible avenues of investigation are explored. [ABSTRACT FROM AUTHOR]

We develop an innovative and unbiased procedure, based on event mixing, to account for unavoidable contributions from volume (or system size) fluctuations to experimentally measured moments of particle multiplicity distributions produced in relativistic nuclear collisions. Within the wounded-nucleon model they are characterized by fluctuations of the number of wounded nucleons, the latter usually referred to as participants. For the first time we extract participant fluctuations directly from the data used for the fluctuation analysis, i.e., without involving model calculations. To achieve this we constructed a dedicated event-mixing algorithm that eliminates all possible correlations between produced particles while preserving the volume fluctuations. The procedure provides direct access to the cumulants of wounded-nucleon distributions, which can be used to account for non-critical contributions to the experimentally measured cumulants of multiplicity distributions. [ABSTRACT FROM AUTHOR]

Particulate matter (PM) collected hourly by an automated sampling unit of the Atmospheric Environmental Regional Observation System (AEROS) was characterized by external micro-particle-induced X-ray emission (PIXE) analysis and imaging. Micro-PIXE analysis revealed the overall elemental composition and differences in the elemental composition ratios of PM 2.5 and PM 2.5-10 collected as individual spots on Teflon tape filters from the unit, and the blank Teflon tape showed a clean background. Moreover, micro-PIXE imaging visualized regions with different elemental compositions in PM 2.5 and PM 2.5-10. Accumulation of PM 2.5 particles was found frequently on tape filters which accounted approximately for 70% of particular elemental composition including heavy metals like iron, compared to that from whole area. The results suggest that PIXE effectively reveals elemental composition of hourly-collected PM by AEROS system for futuristic application for source apportionment of those over Japan. [ABSTRACT FROM AUTHOR]

The structure of the proton exhibits Fractal behavior at low x, where x is the fraction of the proton's momentum carried by the interacting partons. This Fractal behavior is characterized by self-similar properties at different scales and can be quantified using the concept of Fractal dimension. An investigation into the Fractal properties of the proton structure at low x is critical for understanding the fundamental properties of the strong force and developing a more comprehensive understanding of the hadron structure. Fractals, characterized by self-similar patterns across scales, demonstrate a direct correlation between their Fractal dimension and entropy, where higher Fractal dimensions correspond to increased informational content. Furthermore, it is essential for designing high-energy physics experiments and developing more accurate models of subatomic particle interactions. This paper has a fresh look at the self-similar properties of the proton structure at low x. Our study involves the use of the xFitter framework to parameterize the proton structure functions with a Fractal formalism at low x. We also examine how the inclusion of new data affects the results of our analysis. [ABSTRACT FROM AUTHOR]

The delayed-choice experiment is one of the best ways to illustrate the wave-particle duality. The consequences of a quantum delayed-choice experiment have shown that the photon can exhibit dual nature through morphing. There are no hidden variable theories; that can assert the real identities of a photon being a wave and a particle. An open question can emerge, what is the fundamental reason for a photon exposing dual nature. Meanwhile, the recent investigation on photon's 'illusive nature' expounds the apparently unrevealed phenomena like mass posing (zero, real-valued and imaginary rest mass), hidden energy, complex momentum form, and photon possesses this nature for wave-particle duality. The 'illusive nature' could interpret why photon does not hold fixed rest mass like another fundamental particles. This article will find out the cause of wave-particle duality from the outcomes of quantum delayed-choice experiments and the 'illusive nature' of photons. Furthermore, we will figure out a correlation between dual nature and 'illusive nature'. Indeed, a photon might manifest dual nature due to its 'pliable nature'. • The quantum delayed-choice experiments motive to realise the novel 'pliable nature' of a photon. • The 'pliable nature' is the main reason for the manifestation of the dual nature of the photon. • Due to 'dual nature', photons show mass-posing (various forms). • The results agree with the inconsistency of the hidden variable theories. [ABSTRACT FROM AUTHOR]

Plastic deformation in crystalline materials occurs through dislocation slip and strengthening is achieved with obstacles that hinder the motion of dislocations. At relatively low temperatures, dislocations bypass the particles by Orowan looping, particle shearing, cross-slip or a combination of these mechanisms. At elevated temperatures, atomic diffusivity becomes appreciable, so that dislocations can bypass the particles by climb processes. Climb plays a crucial role in the long-term durability or creep resistance of many structural materials, particularly under extreme conditions of load, temperature and radiation. Here we systematically examine dislocation-particle interaction mechanisms. The analysis is based on three-dimensional discrete dislocation dynamics simulations incorporating impenetrable particles, elastic interactions, dislocation self-climb, cross-slip and glide. The core diffusion dominated dislocation self-climb process is modelled based on a variational principle for the evolution of microstructures, and is coupled with dislocation glide and cross-slip by an adaptive time-stepping scheme to bridge the time scale separation. The stress field caused by particles is implemented based on the particle–matrix mismatch. This model is helpful for understanding the fundamental particle bypass mechanisms and clarifying the effects of dislocation glide, climb and cross-slip on creep deformation. [ABSTRACT FROM AUTHOR]

The Alpha Magnetic Spectrometer is a particle physics detector focusing on the search for dark matter, the existence of antimatter, the origin and composition of cosmic rays from primordial sources in the universe and the exploration of new physics in space. Important features of the elementary particle (proton, antiproton, positron and election) fluxes in cosmic rays are presented: (1) The proton spectrum has a smooth hardening from 200 GeV; (2) antiproton and positron spectra show excess from traditional physics background; (3) in particular, the positron flux shows a source term with a cutoff energy of 810 GeV, which raises the question of its source; (4) the origin of the energetic electrons is different from that of positrons and (5) the identical momentum dependence of primary and secondary cosmic ray nuclei fluxes are also reviewed. [ABSTRACT FROM AUTHOR]

We present the charge-changing cross sections (CCCS) of 11−15C, 13−17N, and 15,17−18O at around 300 MeV/nucleon on a carbon target, which extends to p -shell isotopes with N < Z for the first time. The Glauber model, which considers only the proton distribution of projectile nuclei, underestimates the cross sections by more than 10%. We show that this discrepancy can be resolved by considering the contribution from the charged-particle evaporation process (CPEP) following projectile neutron removal. Using nucleon densities from the deformed relativistic Hartree-Bogoliubov theory in continuum, we investigate the isospin-dependent CPEP contribution to the CCCS for a wide range of neutron-to-proton separation energy asymmetry. Our calculations, which include the CPEP contribution, agree well with existing systematic data and reveal an "evaporation peak" at the isospin symmetric region where the neutron-to-proton separation energy is close to zero. These results suggest that analysis beyond the Glauber model is crucial for accurately determining nuclear charge radii from CCCSs. [ABSTRACT FROM AUTHOR]

Two novel approaches to improving the signal-to-background ratio (SBR) for silicon resistive charge-division strip detectors (RSDs), when performing low energy charged-particle spectroscopy, are presented. Firstly, the normally-unutilised rear contact of the detector was used to veto events where the charge collected by this rear face did not match the sum of the charges collected by the strips on the front. Secondly, leading edge discriminator time walk was used to determine complementary information about the hit position along a strip. Using this alongside the position extracted from the charge division allowed clearer identification of true events over background, leading to an improved SBR. These methods were tested by measuring radiation from a triple- α source and then the 12 C( 4 He, α ) α α α breakup reaction at 40 MeV beam energy. The first method was found to improve the SBR by a factor of 4.0(2). The second method gave a SBR improvement of factor of 3.7(4). When both methods are applied together, a total improvement by a factor of 5.7(3) was measured. [ABSTRACT FROM AUTHOR]