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In this paper, the electron scattering transverse and longitudinal form factors for positive low-lying excited states in the 17O nucleus are calculated. The shell model calculation included zbme model space with the rewile interaction using different potentials (HO, WS, Ska, Bsk9) were adopted for the single-particle radial wave function and compared with experimental data. Calculation results indicated that including core-polarization effects together with polarized charge contribution produced better results. [ABSTRACT FROM AUTHOR]

The elastic scattering process Λp → Λp offers insights on multiple problems in nuclear physics. SU(3)F symmetry implies a close agreement between the Λp and pp scattering cross sections. The Λp elastic scattering cross section can also illuminate the structure of neutron stars. A data-mining project was started using multiple CLAS data sets taken for other purposes with photon beams on a long liquid hydrogen target. A Λ produced in a process such as γp → K+ Λ can interact with a second proton inside the target before either decaying or leaving the target. The good angular acceptance and momentum resolution of CLAS make it well-suited for this type of analysis, even though it was not designed for such a measurement. The scattered Λ can be identified from the π− p invariant mass. The four-vector of the initial Λ is then reconstructed in the process Xp → Λp, which shows a strong peak at the Λ mass with roughly twice the number of events as the existing world data sample. This observation opens up the possibility of other measurements using secondary beams of short-lived particles. This paper will discuss the current status of the analysis, and our plans for future work on this project. [ABSTRACT FROM AUTHOR]

The study of the elastic scattering potential on the heavy-ions at various incident energies is a method to investigate the nuclear structures and radii. The cluster structure of the heavy-ions is proposed in order to investigate its reaction potentials. Reaction potentials of the heavy-ions have been a puzzle for many years. In this paper, the cluster structure of the heavy-ions is proposed in order to solve this puzzle. Based on this structure the elastic scattering cross-sections of p+43Ca reaction at Ep = 21--65 MeV are calculated and the results are in agreement with the experimental data. [ABSTRACT FROM AUTHOR]

The discrepancy between the proton charge radius extracted from the muonic hydrogen Lamb shift measurement and the best present value obtained from the elastic scattering experiments, remains unexplained and represents a burning problem of today's nuclear physics: after more than 50 years of research the radius of a basic constituent of matter is still not understood. This paper presents a summary of the best existing proton radius measurements, followed by an overview of the possible explanations for the observed inconsistency between the hydrogen and the muonic-hydrogen data. In the last part the upcoming experiments, dedicated to remeasuring the proton radius, are described. [ABSTRACT FROM AUTHOR]

The discrepancy between the proton charge radius extracted from the muonic hydrogen Lamb shift measurement and the best present value obtained from the elastic scattering experiments, remains unexplained and represents a burning problem of today's nuclear physics: after more than 50 years of research the radius of a basic constituent of matter is still not understood. This paper presents a summary of the best existing proton radius measurements, followed by an overview of the possible explanations for the observed inconsistency between the hydrogen and the muonic-hydrogen data. In the last part the upcoming experiments, dedicated to remeasuring the proton radius, are described. [ABSTRACT FROM AUTHOR]

Small angle scattering (SAS) is the collective name given to the techniques of small angle neutron (SANS) and X-ray (SAXS) scattering. They offer the possibility to analyze particles without disturbing their natural environment. In each of these techniques radiation is elastically scattered by a sample and the resulting scattering pattern is analyzed to provide information about the size, shape and orientation of some component of the sample. Accordingly, a large number of methods and experimental patterns have been developed to ease the investigation of condensed matter by use of these techniques. Some of them are the discussed in this paper. [ABSTRACT FROM AUTHOR]

The MPI/OpenMP/C++ /Fortran package of computer codes has been developed for high-performance numerical analysis of experimental data on elastic nucleus-nucleus scattering within a microscopic model of optical potential. In the package, a modified DWUCK4 Fortran-code for calculating the physical characteristics of elastic scattering based on a numerical solution of the corresponding Schrödinger equation has been incorporated into the C++ framework, which is responsible for the input-output procedure and a comparison of numerical results with experimental data. MPI-based parallelism allows efficient calculations of the observables depending on a wide range of parameters of real and imaginary parts of the microscopic optical potential. The package has been used to analyze experimental data on differential cross sections of nucleus-nucleus elastic scattering of neutron-rich exotic nuclei 12,14Be on the target nucleus 12C at energy about 56 MeV/nucleon. [ABSTRACT FROM AUTHOR]

In order to model and diagnose the low-temperature edge plasmas, a complete database for electron-impact collision processes is required for molecular species containing beryllium and hydrogen. Dominant elementary processes in cold ionized gases are dissociative recombination, elastic collisions, vibrational excitation, vibrational de-excitation and dissociative excitation. In this study, using the stepwise version of the Multichannel Quantum Defect Theory, cross sections and rate coefficients have been obtained for reactions induced on BeT+. A set of vibrational resolved rate coefficients for BeT+ cations' reactive collisions with electrons below to the ion dissociation threshold is provided. The incident electron energy range is 10-3 - 2.7 eV and the electron temperature range is 100 - 5000 K. [ABSTRACT FROM AUTHOR]

A model that allows interpretation of positron annihilation spectra (LT and CDB) in nanodispersed dielectric powders is developed. Model takes into account e+ capture by vacancy-type defects, formation of e+ surface-bound states, as well as the formation of quasi-free positronium (inside crystallites) which may escape into intergranular space where it becomes thermalized during elastic collisions. The process of annihilation of ortho-Ps is narrowed down to its conversion into the para-state as a result of collisions with oxygen molecules (O2) adsorbed on the surface of crystallites. A computer program for lifetime spectra fitting that accounts on the parameters of the above model is developed (with ROOT framework). Combination of the program with our CDB software allows joint processing of the LT and CDB annihilation spectra of nanopowders. [ABSTRACT FROM AUTHOR]

The elastic and inelastic scatterings of α-particles were investigated at an energy of 29 MeV with excitation of lowlying states of the 11B nucleus. As a result of research we obtained new experimental data for the α + 11B inelastic scattering one leading to the 2.12 MeV (1/2−), 4.44 MeV (5/2−) and 6.74 MeV (7/2−) excited states of 11B nucleus. In the framework of Modified diffraction model, the root mean square radii of these excited states are calculated. The theoretical calculations for the concerned excited states were performed using the coupled channel (CC) method. [ABSTRACT FROM AUTHOR]

We describe the implementation of kinetic solvers in 1d2v phase space using adaptive Cartesian mesh. Spherical coordinates in velocity space are used to simplify the Lorentz and Fokker-Planck collisional operators. The key capabilities of the new solvers are illustrated for electron elastic scattering, acceleration, continuous energy loss in collisions, and ionization processes in weakly-ionized plasma. We have also implemented two-stream approach to reduce computational cost for studies of gas breakdown dynamics in the presence of runaway electrons. The benefits and limitations of the nonsplit- phase-space method for kinetic solvers with adaptive mesh in phase space are discussed. [ABSTRACT FROM AUTHOR]

A model of scattering of elastic wave by point-like scatterer on the plane is suggested. Point-like perturbation is constructed for the Lamé operator in the framework of the theory of self-adjoint extensions of symmetric operators. The eigenvalues of the model operator are found. The scattering matrix is obtained. [ABSTRACT FROM AUTHOR]

Boundary integral equations methods are inherently advantageous for infinite medium problems such as elastic wave scattering for ultrasonic Nondestructive Testing. The reduction in dimensionality of the problem (e.g., volume to surface) also leads to computational advantages versus finite element or finite difference methods for homogeneous media. However, numerical integration of the strongly singular (1/r²) kernels of the traditional BIE formalism has been a challenge in implementation; although successful functioning codes have long existed. Still, methods to incrementally minimize this difficulty have been the subject of research for three decades. This new BIE method utilizes an analytical representation for the incident plane wave’s stress field and Betti reciprocity to eliminate the strongly singular kernel integration that is required by scatterers with stress-free boundary conditions (such as voids, open cracks, and any nearby free surfaces). An associated weakly singular (1/r) BIE is readily solved instead. [ABSTRACT FROM AUTHOR]

Elastic scattering reactions have been part of a campaign of studies at the Cyclotron Institute from Texas A&M University for more than 30 years. The studied nuclei ranged from 8Be to 22Ne. In order to study the astrophysically important 26Si (through its mirror 26Mg), it was necessary to perform an upgrade of the focal plane detection system. Several scattering reactions on nuclei heavier than A=22 were measured as tests and the preliminary results are presented here. [ABSTRACT FROM AUTHOR]

The glue-like behavior of valence neutrons has been investigated in the Li isotopes. The 7Li nucleus is well known to be weakly bound system with the α + t cluster structure. By adding the valence neutrons, the reduction of the root-mean-square (RMS) radius of the proton density for the 7Li, 8Li and, 9Li nuclei is also well known from the viewpoint of the experimental data and theoretical approach. Elastic scattering cross sections of the Li isotopes on the 12C and 28Si targets at E/A～50 MeV are calculated. We find the change of the channel coupling (CC) effect on elastic scatterings of such Li isotopes by the glue-like role of the valence neutrons. Finally, we realize that the valence neutrons stabilize the binding of core parts, and the CC effect related the core excitation is indeed reduced. [ABSTRACT FROM AUTHOR]

The proposed theoretical model allows for the perfectly elastic collision of three bodies (three mass points) to calculate: 1) the definite value of the three bodies’ projected velocities after the collision with a straight line, along which the bodies moved before the collision; 2) the definite value of the scattering bodies’ velocities on the plane and the definite value of the angles between the bodies’ momenta (or velocities), which the bodies obtain after the collision when moving on the plane. The proposed calculation model of the velocities of the three collided bodies is consistent with the dynamic model of the same bodies’ interaction during the collision, taking into account that the energy flow is conserved for the entire system before and after the collision. It is shown that under the perfectly elastic interaction during the collision of three bodies the energy flow is conserved in addition to the momentum and energy conservation. [ABSTRACT FROM AUTHOR]

The elastic α-12C scattering at low energies is studied in the cluster effective field theory, in which the ground states of α and 12C are treated as elementary-like fields. We first discuss a construction of an effective field theory for radiative α capture reaction on 12C at the Gamow energy, TG = 0.3 MeV, in the stars and fix some parameters appearing in the theory from the phase shift data of the elastic α-12C scattering. We then discuss the uncertainties of the present approach when interpolating the scattering amplitudes to TG. [ABSTRACT FROM AUTHOR]

We consider dark matter as an analog of hydrogen in a secluded sector and study its astrophysical implications. The self interactions between dark matter particles include elastic scatterings as well as inelastic processes from hyperfine transitions. We show that for a dark hydrogen mass in the 10-100 GeV range and a dark fine-structure constant larger than 0.01, the self-interaction cross section has the right magnitude and velocity dependence to explain the low dark matter density cores seen in small galaxies while being consistent with all constraints from observations of galaxy clusters. Excitations to the hyperfine state and subsequent decays, however, may cause significant cooling losses and affect the evolution of low-mass halos. We also find minimum halo masses in the range of 103.5-107 M..., which are significantly larger than the typical predictions for weakly interacting dark matter models. This pattern of observables in structure formation is unique to this model, making it possible to determine the viability of hidden-sector hydrogen as a dark matter candidate. [ABSTRACT FROM AUTHOR]

We discuss diphoton semi(exclusive) production in ultraperipheral PbPb collisions at energy of ysNN = 5.5 TeV (LHC). The nuclear calculations are based on equivalent photon approximation in the impact parameter space. The cross sections for elementary γγ → yy subprocess are calculated including three different mechanisms: box diagrams with leptons and quarks in the loops, a VDM-Regge contribution with virtual intermediate hadronic excitations of the photons and the two-gluon exchange contribution (formally three-loops). We got relatively high cross sections in PbPb collisions. This opens a possibility to study the γγ → γγ (quasi)elastic scattering at the LHC. We find that the cross section for elastic γγ scattering could be measured in the lead-lead collisions for the diphoton invariant mass up to ψ γγ 15 - 20 GeV. We identify region(s) of phase space where the two-gluon exchange contribution becomes important ingredient compared to box and nonperturbative VDM-Regge mechanisms. We discuss also first results concerning production of two e+e-pairs in UPCs of heavy ions. We considered only double scattering mechanism. [ABSTRACT FROM AUTHOR]

Elastic scattering of relativistic spin 1/2 particle was investigated in the spherically-symmetric case. Based on the phaseshift method, a general solution of the Dirac equation with superposition of N δ-potentials is obtained. The method for approximate solutions of Dirac equation with arbitrary smooth potentials is presented. Scattering cross section dependences on various parameters are investigated. [ABSTRACT FROM AUTHOR]

In the plumes of Hall thrusters and ion thrusters, high energy ions experience elastic collisions with slow neutral atoms. These collisions involve a process of momentum exchange, altering the initial velocity vectors of the collision pair. In addition to the momentum exchange process, ions and atoms can exchange electrons, resulting in slow charge-exchange ions and fast atoms. In these simulations, it is particularly important to accurately perform computations of ion-atom elastic collisions in determining the plume current profile and assessing the integration of spacecraft components. The existing models are currently capable of accurate calculation but are not fast enough such that the calculation can be a bottleneck of plume simulations. This study investigates methods to accelerate an ion-atom elastic collision calculation that includes both momentum- and charge-exchange processes. The scattering angles are pre-computed through a classical approach with ab initio spin-orbit free potential and are stored in a two-dimensional array as functions of impact parameter and energy. When performing a collision calculation for an ion-atom pair, the scattering angle is computed by a table lookup and multiple linear interpolations, given the relative energy and randomly determined impact parameter. In order to further accelerate the calculations, the number of collision calculations is reduced by properly defining two cut-off cross-sections for the elastic scattering. In the MCC method, the target atom needs to be sampled; however, it is confirmed that initial target atom velocity does not play a significant role in typical electric propulsion plume simulations such that the sampling process is unnecessary. With these implementations, the computational runtime to perform a collision calculation is reduced significantly compared to previous methods, while retaining the accuracy of the high fidelity models. [ABSTRACT FROM AUTHOR]

We suggest new methods to extract elastic (quasi-elastic) scattering angular distribution and reaction (capture) cross sections from the experimental elastic (quasi-elastic) backscattering excitation function taken at a single angle. [ABSTRACT FROM AUTHOR]

We describe systematically by collision energy and target mass, alpha elastic scattering angular distributions by using the São Paulo potential as the real part of the optical potential. The imaginary part is proportional to the real one by a factor Ni. We find this parameter by fitting the theoretical angular distributions to the experimental cross sections through a χ2 minimization. The Ni and their respective uncertainties, σNi, fall in the range 0.4 ≤ Ni ± σNi ≤ 0.8 for all the systems studied. [ABSTRACT FROM AUTHOR]

The behavior of specimens dynamically loaded during split Hopkinson (Kolsky) bar tests in a regime close to simple shear conditions was studied. The lateral surface of the specimens was investigated in-situ using a high-speed infrared camera CEDIP Silver 450M. The temperature field distribution obtained at different time allowed one to trace the evolution of plastic strain localization. The process of target perforation involving plug formation and ejection was examined using a high-speed infrared camera and a VISAR velocity measurement system. The microstructure of tested specimens was analyzed using an optical interferometer-profiler and a scanning electron microscope. The development of plastic shear instability regions has been simulated numerically. [ABSTRACT FROM AUTHOR]

A kinetic model for He-H2 mixtures is studied in a regime where elastic collisions are fast and inelastic collisions are slow. Application of the Chapman-Enskog method yields a state to state fluid model where each quantum state is a separate pseudo species. The relaxation of quantum state population towards thermodynamic equilibrium is investigated as well as the definition of volume viscosity coefficients. The theoretical results are applied to the quantum state population and volume viscosity of molecular hydrogen on the basis of a complete set of cross sections for the He+H2(v, j) system. [ABSTRACT FROM AUTHOR]

The low-temperature behavior of the specific heat in disordered nanotubes strongly depends on structure changes and was not explained by the phonon contribution. Expression for electronic specific heat was carried out taking into account the multiple elastic scattering of electrons on impurities and structural inhomogeneities of short-range order type, it includes dependence on diameter of nanotube, concentration of impurities, parameters of short-range order (structural heterogeneity) and temperature. Anomalous low-temperature behavior of the specific heat of disordered CNT is shown to have electronic nature and may be associated with the electrons that are involved in restructuring. [ABSTRACT FROM AUTHOR]