<Emphasis Type="Italic">η</Emphasis><Superscript>7</Superscript>Li Scattering in the <Emphasis Type="Italic">αt</Emphasis>-Cluster Model

The cross sections for elastic and inelastic η-meson scattering on ⁷Li nuclei are obtained on the basis of the αt-cluster representation of the target nucleus. The experimentally known values of the parameters of elastic ηα and αt scattering are used in exactly solving three-body Faddeev equations with separable two-body potentials. The η⁷Li elastic-scattering scattering length found from respective calculations is a_η7Li = ?0.310 ? i0.198 fm.     

Electron-phonon interaction in a free standing beryllium monolayer

We report ab initio study of the electron-phonon coupling in a free standing Beryllium monolayer. The calculations were carried out using a linear-response approach in the plane-wave pseudopotential representation. The Eliashberg spectral function α²F(ω) and the electron-phonon coupling parameter λ are evaluated at the Fermi level. The obtained results show a large contribution to the electron-phonon coupling from the low-energy transverse mode scattering.     

Watson representation for the amplitude of lepton-pair production in nucleus-nucleus collisions

An expression for the amplitude of lepton pair production in nucleus-nucleus collisions is obtained in terms of the amplitudes of lepton-nucleus scattering. By using this representation an approximate compact expression for this amplitude valid to terms of the order (Zα)⁵ is obtained.     

The time fractional heat conduction equation in the general orthogonal curvilinear coordinate and the cylindrical coordinate systems

In this paper a time fractional Fourier law is obtained from fractional calculus. According to the fractional Fourier law, a fractional heat conduction equation with a time fractional derivative in the general orthogonal curvilinear coordinate system is built. The fractional heat conduction equations in other orthogonal coordinate systems are readily obtainable as special cases. In addition, we obtain the solution of the fractional heat conduction equation in the cylindrical coordinate system in terms of the generalized H-function using integral transformation methods. The fractional heat conduction equation in the case 0<α≤1 interpolates the standard heat conduction equation (α=1) and the Localized heat conduction equation (α→0). Finally, numerical results are presented graphically for various values of order of fractional derivative.     

On the shapes of136,138Pm

The differential cross-section for elastic scattering ofα-particles on¹²C nucleus at 1.37 GeV is calculated on the basis of multiple diffraction scattering theory andα-cluster model with dispersion. The parameters of effectiveα-α amplitude are obtained from the fitting of 1.37 GeVα-¹²C differential cross-section. It is shown that interactions ofα-particles inside the nucleus differ significantly as compared with those of freeα-particles.     

Binding energy of triton and scattering lengths in neutron-deuteron collision in Faddeev formalism with local potential

A separable representation for the off-shell two-body t-matrix for a local Hulthén potential is presented, in which deuteron states are chosen as the expansion bases. Using the Faddeev equations with these t-matrices as input, the ground state energy of the triton and doublet and quartet scattering lengths in neutron-deuteron scattering, have been computed. The results have been compared with the experimental findings and the theoretical results of Sitenko et al. obtained in the Sturmian function representation with the same Hulthén potential.     

SS-HORSE Method for Analysis of Resonances: Charged-Particle Scattering

The method for analyzing resonance states based on the harmoni©oscillator representation of scattering equations (HORSE) and on analytic properties of partial-wave scattering amplitudes which has been proposed earlier, is generalized to the case of charged-particle scattering. The method in question is tested by applying it to the model problem of pα scattering and can be used to study resonance states on the basis of microscopic calculations within various versions of the shell model.     

Phase-function method for elasticα-α scattering

The phase-function method is adapted to deal with scattering on Coulomb plus nonlocal separable potentials. The Coulomb effect is included rigorously and a closed form expression is obtained for the scattering phase shiftδ _l (k). Based on the expression forδ _l (k) we present results forα-α elastic scattering phases which compare very well with more detailed calculations.     

High energy proton-carbon scattering in the alpha-particle model

We investigate elastic and inelastic 0⁺–2⁺ high energy proton-¹²C scattering in the alpha-particle model. We use a rigid equilateral triangle nuclear wave function with a Gaussian dispersion function allowing theα-particles of the¹²C-nucleus to deviate from their most probable positions at the triangle vertices. Expressions for the differential scattering cross sections are deduced using Glauber multiple diffraction theory. Thus we need thep?α-particle scattering amplitude, which is calculated from a Gaussian nucleon-nucleon profile function. Numerical calculations show that the model reproduces the experimental results onp?α andp-¹²C scattering.     

Analytic continuation of the effective-range expansion as a method for determining the features of bound states: Application to the 6Li nucleus

The scattering function (effective-range function) for the two-channel elastic scattering of charged particles is used to analyze dα scattering at low energies. In order to construct this function, use is made of various sets of phase shifts and mixing parameter, both those that were obtained by solving Faddeev equations in the three-body (n, p, α) model and those that were deduced from available phaseshift analyses. By means of an analytic continuation of the scattering function to the point of the pole corresponding to the bound state of the ⁶Li nucleus, the values of the vertex constants and asymptotic normalization coefficients are found for the process ⁶Li → α + d. Possible means for refining these results are discussed.     

The Fourier-Bessel expansion of the scattering amplitude at zero momentum transfer for particles with unequal mass

We investigate the problem of whether a Fourier-Bessel type expansion can be valid at zero-momentum transfer for the unequal-mass scattering amplitude, as a substitute for the Regge-Watson-Sommerfeld representation. It is shown that the results of a previous paper, giving the solution of the same problem for amplitudes satisfying an unsubtracted dispersion relation can be extended to a class of asymptotically growing scattering amplitudes. In the second part of the paper a Lorentz-pole expansion is outlined, which is valid at arbitrary momentum transfer. The expansion coefficients of this last expansion are expressed by means of the discontinuities of the amplitudes. Finally, a comparison is made between the Fourier-Bessel expansion and the Lorentz expansion. We argue that, at least as far as the unequal-mass formulas are concerned, it is highly unnatural to assume that a pomeron with intercept α(0) = 1 belongs purely to the four-vector representation of the Lorentz group. Rather, it is a mixed object belonging to the four-dimensional and the accompanying infinite-dimensional ones, both characterized by the same Casimir operator eigenvalues.     

Non-coherent scattering

The paper is devoted to the consideration of the problems of non-coherent scattering in a spectral line for an arbitrary redistribution law. The representation of the redistribution function r(x′,x) in the form

$\text{r(χ′,χ) =}\text{∑}\text{k = 1}\text{∞}\text{A}{}_{\mathrm{k}}\text{α}{}_{\mathrm{k}}\text{(χ′)α}{}_{\mathrm{k}}\text{(χ)}$

is used to study the various mechanisms of line broadening. The form of representation plays an important role in this investigation. New methods for solving radiative transfer integro—differential equations, as well as the corresponding integral equations are suggested. The solution of integral equations involves factorization of matrix integral operators. The generalized classical problems of absorption-line formation in stellar atmospheres are formulated and solved (Shuster's and Eddington's models). The results of numerical calculations, carried out to the fourth order, are given for Doppler broadening.     

Coupled-channel R-matrix method on a Lagrange mesh

The coupled-channel R-matrix method on a Lagrange mesh is a very simple approximation of the R-matrix method with a basis. The mesh points are zeros of shifted Legendre polynomials. Bound-state energies and scattering matrices are easily calculated with small numbers of potential values at mesh points. A test with an exactly solvable two-channel potential provides an excellent accuracy over a broad energy range with only 30 mesh points. The efficiency of the method is illustrated for a single channel on α + α scattering and for two channels on the deuteron ground-state energy and on nucleon-nucleon scattering.     

Elastic α+28Si scattering — thick target measurements and results

Excitation functions for elasticα-particle scattering from a thick target have been measured. The formalism developed for elemental analysis has been adopted to calculate cross sections. Results fromα+²⁸Si elastic scattering,E _α=6.5?19 MeV, are presented. Spins have been deduced from angular distributions and are shown to form a rotational band with odd and even parities. This result is compared to an old GCM phase shift prediction taken from literature.     

Model independent evaluation of the inelastic e− scattering cross sections from the 3− (2.615 MeV) level in 208Pb

The radial transition charge density and the reduced transition probability of the 3^? level in ²⁰⁸Pb are determined model independently from inelastic e^? scattering cross sections. The results are compared with (α, α') experiments and theoretical calculations.     

Higgs boson production by W and Z collisions

A general formulation for the WW → H and ZZ → H mechanisms of heavy Higgs boson production in hadron colliders is presented. The known results in the effective W approximation are obtained from the quark-parton model limit of the double inelastic scattering configuration. In addition contributions from the elastic scattering configurations and from α_s-processes of QCD are estimated.     

Elastic scattering of light nuclei through a simple potential model

The phase function method is adapted to deal with the scattering on our proposed interactions for α–α and α–³He systems. The effect of the electromagnetic interaction is included in terms of a screened Coulomb potential. Based on our proposed potential models we present results for α–α and α–³He elastic scattering phase shifts which compare well with more detailed calculations.     

Experimental study of the spindynamics in the 1-D-ferromagnet with planar anisotropy,CsNiF3, in an external magnetic field

The results of a detailed inelastic neutron scattering study of the spindynamics in CsNiF₃ in an external magnetic field are presented. Results have been obtained for different combinations of the correlation function <S ^α S^α> (α=x, y, z) in order to analyse theH, T, q _c-dependence of both, the central component and the spinwave scattering. These results cannot be explained by a multispin-wave theory alone, but it is necessary to introduce solitons in order to describe the experimental findings. It is found that under certain conditions the contribution from solitons and from two-spinwave processes have the same size. These results show that the spindynamics in this system in fields 2.5kOe<H<10kOe and5K≦...15K are similar to that in a sine-Gordon system. ForT>15K this picture breaks down probably due to the finite size of the easy plane anisotropy energy.     

Production representation of partial wave scattering amplitudes and the fo（600） particle

The establishlnent of production representation of partial wave scattering alnplitudes is reviewed in the context of quantum field theory. Its relation to the production representation, or Ning Hu representation in quantum mechanical scattering theory is pointed out. One of the most important application of the production representation is the physics of the fo（600） and K（700） scalar hadron resonances, on which we also give a brief review. It is emphasized that all evidences accunmlated so far are consistent with the picture that the fo（600） meson is the chiral partner of the Nambu Goldstone bosons in a linear realization of chiral symmetry.     

Study of the inclusive inelastic reaction α + α → α + X at 4.32 GeV/c and 5.07 GeV/c in the forward direction

The reaction α + α → α + X was measured between 3° and 11° in the laboratory, at 4.32 GeV/c and 5.07 GeV/c incident momenta. The spectra are described as an incoherent sum of quasielastic scattering on substructures of the α-target. These quasielastic cross sections have a diffractive form comparable to that of the known elastic scattering process. They are reproduced by Glauber-model calculations which use radii for these substructures much smaller than those of the free nuclei.