Optical potential analysis of proton elastic scattering from <Superscript>12</Superscript>C based on the <Emphasis Type="Italic">α</Emphasis>-particle model

Based on an α-particle model of ¹²C, an optical potential for intermediate-energy proton- ¹²C scattering is presented in the framework of the KMT theory. The parameterized proton- ⁴He amplitude, the required basic input for constructing the optical potential, is obtained by fitting the proton- ⁴He scattering data. The differential cross-sections and analyzing powers of the proton- ¹²C elastic scattering at incident energies ranging from 0.2 to 1.0GeV have been calculated by using the obtained optical potential. The main features of the measured angular distributions of the cross-section and the analyzing power can be satisfactorily described. The proton- ¹²C total cross-sections have also been calculated, and the results are in good agreement with the experimental data at energies below 0.6GeV but underestimate the data about 6% at higher energies.     

Search for missing baryon resonances via associated strangeness photoproduction

Differential cross-section and single polarization observables in the process γp→K ⁺ Λ are investigated within a constituent-quark model and a dynamical coupled-channel formalism. The effects of two new nucleon resonances and of the K ^*(892)- and K1(1270)-exchanges are briefly presented.     

Electromagnetic wave propagation through frequency-dispersive and lossy double-negative slab

This study presents the electromagnetic wave propagation through the frequency-dispersive and lossy double-negative slab embedded between two different semi-infinite media. The double-negative slab is realized by using two models, the Lorentz and Drude medium models. The properties and the required equations for the frequency-dispersive and lossy double-negative slab, the Lorentz medium and Drude medium are given in detail. After the construction of the problem, the reflection and transmission coefficients are derived for both TE and TM waves. Then, the reflected, transmitted and loss powers are determined using these coefficients. Finally, in the numerical results, the mentioned powers for TE and TM waves are computed and illustrated as a function of the incidence angle, the frequency and the slab thickness when the damping frequency changes.     

Electromagnetic proton-neutron knockout off <Superscript>16</Superscript>O : New achievements in theory

Results for the cross-sections of the exclusive ¹⁶O(e, e'pn)¹⁴N and ¹⁶O(γ, pn)¹⁴N knockout reactions are presented and discussed in different kinematics. In comparison with earlier work, a complete treatment of the center-of-mass (CM) effects in the nuclear one-body current is considered in connection with the problem of the lack of orthogonality between initial bound and final scattering states. The effects due to CM and orthogonalization are investigated in combination with different treatments of correlations in the two-nucleon overlap function and for different parametrizations of the two-body currents. The CM effects lead in super-parallel kinematics to a dramatic increase of the ¹⁶O(e, e'pn) cross-section to the 1₂ ⁺ excited state (3.95MeV) of ¹⁴N . In all the situations considered the results are very sensitive to the treatment of correlations. A crucial role is played by tensor correlations, but also the contribution of long-range correlations is important.     

Calculation of the Effect on the Reflection of the Plane Electromagnetic Wave for Non-Magnetized Plasma with Different Electron Density Distributions

In this paper, shift operator finite-difference time-domain (SO-FDTD) method is applied for the calculation of the dispersive medium. The high efficiency and accuracy of this method is verified by calculating the reflection of the plane electromagnetic wave impinging on a non-magnetized plasma slab with different electron density distributions. The results show that the average electron density only determines overall trends of the reflection, and different distributions affect the oscillating process of the reflection. If the average electron density maintains the same, the distribution of electron density with homogenous or inhomogeneous alternation will sharply take effects on the reflection. And magnitude of alternation of electron density affects the incident frequency directly when the reflection tends to uniform.     

Implications of the nuclear EMC effect

The discovery more than twenty years ago, by the EMC Collaboration, that the deep-inelastic-scattering DIS structure functions are influenced by the nuclear environment stunned the nuclear physics community and brought quarks and gluons into the field with great impact. A great length of time has passed, but despite a semi-infinite number of papers on the subject, there is no explanation that is universally accepted. Many models (related in one way or another to QCD) have been successful in reproducing data for deep inelastic scattering on nuclear targets, but fewer have described both the DIS and nuclear Drell-Yan experiments. Although there are some positive indications, no model has been used to predict correctly and unambiguously new independent phenomena. We review the history and discuss the best experimental prospects for future discovery.     

The Analysis of Scattering Effect for the Transmission of 1.06?μm Laser In Lower Altitude Atmosphere

On the basis of Mie’s scattering theory, the light scattering properties of atmospheric molecules and aerosol particles are analyzed and a forward-scattering model for atmospheric transmission in city outskirts is built. Through theoretical analysis and the numerical calculations to the irradiance distribution of the 1.06 μm pulse laser while transmitting in lower altitude atmosphere, we can draw some conclusions which provide usable information for the research and manufacture of off-axis scattering warning systems.     

Beam normal spin asymmetries: Theory

The beam normal spin asymmetry in elastic electron-nucleon scattering is discussed. This beam normal spin asymmetry depends on the imaginary part of two-photon exchange processes between electron and nucleon, and measures the non-forward structure functions of the nucleon. After briefly reviewing the theoretical formalism, we discuss calculations in the threshold region, in the resonance region, as well as in the diffractive region, corresponding with high energy and forward angles.     

Stimulated Brillouin scattering in magnetized diffusive semiconductor plasmas

Using the hydrodynamical model and following the coupled mode approach, detailed analytical investigation of stimulated Brillouin scattering is performed in an electrostrictive semiconductor. The total induced current density including diffusion current density and the effective Brillouin susceptibility are obtained under off-resonant laser irradiation. The analysis deals with the qualitative behaviour of the Brillouin gain and transmitted intensity with respect to excess doping concentration and magnetic field. Efforts are directed towards optimizing the doping level and magnetic field to achieve maximum Brillouin gain at pump intensities far below the optical damage threshold level. It is found that by immersing a moderately doped semiconductor in a sufficiently strong magnetic field in transverse direction, one can achieve resonant enhancement of Brillouin gain provided the generated acoustic mode lies in the dispersionless regime.     

Two-period model for calculation of level populations in subbands of multi-period quantum-cascade superlattice structures

For two periods of quantum-cascade laser structures, we propose a system of closed balance equations that make it possible to calculate the occupancy of the energy levels, the quasi-Fermi levels, and also the injection current density taking into account different charge carrier scattering mechanisms. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 74, No. 6, pp. 801–804, November–December, 2007.