Phänomenologische Behandlung der elastischen Streuung von Spin-1-Teilchen an Spin-0-Teilchen

The elastic scattering of spin 1 particles by spin 0 particles is treated in terms of the WolfensteinM-matrix. The purpose of these calculations is to find a method which allows to measure vector and tensor polarization of a spin 1 particle beam scattered by a spin 0 target and to find out experiments which determine all parameters of theM-matrix. The scattering cross section for double and triple scattering has been calculated. The discussion shows, that the use of a polarized ion source is much more favorable than the conventional double and triple scattering technique.     

Growth of nuclear spin precession frequency of antiprotons (negative hyperons) under deceleration in matter with polarized nuclei

The Coulomb interaction leads to an increase of the real part of the amplitude of scattering of negatively charged particles (antiprotons, hyperons) by nuclei. In consequence, when antiprotons (negative hyperons) are decelerated in a medium with polarized nuclei, their effective energy of interaction with the medium and the nuclear spin precession frequency in a pseudomagnetic field grow as the particles decelerate. As a result, spin rotation of negatively charged particles becomes observable despite their rapid deceleration. This provides information about the spin-dependent part of the amplitude of coherent elastic zero-angle scattering in the range of low energies, where scattering experiments are practically impossible to perform.     

Pre-Asymptotic Analysis of the Scattering Problem

JETP Letters - The pre-asymptotic analysis of the multichannel scattering problem for particles with an arbitrary spin and short-range interactions has been presented. The complete operator-valued...     

Analytical Expressions for the Differential Elastic Scattering Cross Sections of Nonidentical Nuclear Particles with Channel Spin 1 and 2

Russian Physics Journal - Analytical expressions for calculation of the differential elastic scattering cross sections of two particles for channels with integer value of the spin equal to 1 and 2...     

Dynamics of polarization buildup by spin filtering

There has been much recent research into polarizing an antiproton beam, instigated by the recent proposal from the PAX (Polarized Antiproton eXperiment) project at GSI Darmstadt. It plans to polarize an antiproton beam by repeated interaction with a polarized internal target in a storage ring. The method of polarization by spin filtering requires many of the beam particles to remain within the ring after scattering off the polarized internal target via electromagnetic and hadronic interactions. We present and solve sets of differential equations which describe the buildup of polarization by spin filtering in many different scenarios of interest to projects planning to produce high-intensity polarized beams. These scenarios are: 1) spin filtering of a fully stored beam; 2) spin filtering while the beam is being accumulated, i.e. unpolarized particles are continuously being fed into the beam; 3) the particle input rate is equal to the rate at which particles are being lost due to scattering beyond the ring acceptance angle, the beam intensity remaining constant; 4) increasing the initial polarization of a stored beam by spin filtering; 5) the input of particles into the beam is stopped after a certain amount of time, but spin filtering continues. The rate of depolarization of a stored polarized beam on passing through an electron cooler is also shown to be negligible.     

Hyperbolic-like elastic scattering of spinning particles by a Schwarzschild black hole

The scattering of spinning test particles by a Schwarzschild black hole is studied. The motion is described according to the Mathisson–Papapetrou–Dixon model for extended bodies in a given gravitational background field. The equatorial plane is taken as the orbital plane, the spin vector being orthogonal to it with constant magnitude. The equations of motion are solved analytically in closed form to first-order in spin and the solution is used to compute corrections to the standard geodesic scattering angle as well as capture cross section by the black hole.     

Dynamics of the magnetic moment in a polarized Boltzmann gas allowing for dissipation

An equation is derived for the dynamics of the spin magnetic moment in a polarized Boltzmann gas allowing for spin loss processes. The general form of the T matrix for collisions between two spin 1/2 particles allowing for inelastic processes is used. It is shown that the rate of spin loss depends on the degree of polarization of the gas. As a result, the damping of deviations of the magnetic moment from the average becomes anisotropic where the degree of anisotropy depends on the amplitude of the zero-angle scattering of atoms.     

Spin rotation and oscillation of high energy particles in storage ring

Phenomena of rotation and oscillations of particle spin are discussed for particles rotating in storage ring. The fact that these effects are described by spin-dependent part of zero-angle scattering amplitude allows to use them for the measurement of this amplitude at different energies of colliding particles. It is shown that effect magnitudes are large and they can be observed at the existing accelerators.     

Entwicklung der Streuamplituden nach irreduziblen Spintensoroperatoren

The scattering amplitude for elastic or inelastic scattering of nonrelativistic particles with spin is calculated from the angular momentum representation of theS-matrix. Application of Racah algebra techniques allows a representation in terms of irreducible spin-tensor operators. Only two particle channels are considered. The physical significance of the invariant expansion coefficients of that representation is illustrated in the well known case of nucleon nucleon scattering.     

Two particle unitarity for helicity amplitudes with particles of arbitrary spin

The two particle unitarity contribution to the double spectral function of the scattering amplitude for any 2 → 2 process is explicitly calculated for the case of arbitrary spins of the initial, intermediate and final particles. A closed, simple result is obtained which is a generalization of the Mandelstam result for spinless particles. The results should be of value in calculations of the contribution of the exchange of pairs of high spin particles to the nucleon-nucleon force.     

Electron level quantization effects in small tin particle

The electron spin susceptibility was measured in small Sn particles by means of NMR Knight shift. The quenching of the spin-orbit scattering by the electron level quantization was observed.     

Cluster effects in the angular distribution of alphas scattered from34S

The addition of a resonance scattering contribution to the shape elastic scattering improves the fit in analysing experimental angular distributions. Spins from 7 to 10 ? characterize the resonances, which have a dominant influence on the six analysed angular distributions of 12.80 to 20 meV alpha particles elastically scattered from³⁴S. The relation between the energy of the resonances and their spin compares well with the results from alpha scattering from²⁸Si. As in the scattering from silicon, the occurrence of a dominating spins supports the assumption that they belong to cluster states formed when alpha particles hit the target nuclei.     

Quantum insulating states of F=2 cold atoms in optical lattices

In this Letter we study various spin correlated insulating states of F=2 cold atoms in optical lattices. We find that the effective spin exchange interaction due to virtual hopping contains an octopole coupling between two neighboring lattice sites. Depending on scattering lengths and numbers of particles per site the ground states are either rotationally invariant dimer or trimer Mott insulators or insulating states with various spin orders. Three spin-ordered insulating phases are ferromagnetic, cyclic, and nematic Mott insulators. We estimate the phase boundaries for states with different numbers of atoms per lattice site.     

Scattering of ultrarelativistic deuterons by nuclei

Theoretical study of the interaction of ultrarelativistic hadrons with one another and with nuclei is stimulated by a number of experiments on the scattering of these particles with energies of ten billion electronvolt and more. It is difficult to explain the data obtained in such experiments because of the absence of a consistent relativistic quantum theory of hadrons. However, the existing experiments on the interaction of hadrons with hadrons and nuclei at high and superhigh energies can be well described phenomenologically in the framework of the diffraction approximation [1, 2], which was also used successfully earlier but at much lower, nonrelativistic energies [3, 4]. In the present paper, we derive a general formula for Hyugens's principle for monochromatic vector waves describing particles with spin 1 (for example, deuterons); this is used to obtain formulas for the cross sections of elastic and inelastic (accompanied by the emission of photons without disintegration of the particles) scattering of ultrarelativistic deuterons by nuclei with allowance for the spin and structure of the deuteron and the target nucleus; some special cases are also considered. The internal structure of the colliding nuclei, and also the possibility of excitation and disintegration of the target nuclei are taken into account by means of a generalization of the diffraction method to the case of the collision of any two nuclei, consideration being given to the interaction between each nucleon of the incident nucleus and all the nucleons of the target nucleus. In particular, this generalizes the results of [3–6] (in which diffraction scattering of elementary charged particles with spins 0, 1/2, and 1 with emission of photons was studied) to the case of composite incident particles with spin.Translated from Izvestiya Vysshikh Uchbenykh Zavedenii, Fizika, No. 9, pp. 3–8, September, 1980.     

The new identity for the scattering matrix of exactly solvable models

We discovered a simple quadratic equation, which relates scattering phases of particles on Fermi surface. We consider one-dimensional Bose gas and XXZ Heisenberg quantum spin chain. Received: 4 December 1997 / Accepted: 17 March 1998     

Polarizations of spin 32 particles and 7Li58Ni interactions

New representations of polarizations of spin $\text{3}\text{2}$ particles are proposed for elastic scattering. They are useful in investigating spin-dependent interactions. The application to ⁷Li⁵⁸Ni scattering gives weak spin-orbit interactions and rather strong tensor ones of ⁷Li.     

Fresnel corrections in the relativistic scattering of particles with spin 0 and 1/2

The corrections to the eikonal scattering amplitude are investigated. The Fresnel corrections to the eikonal solution of a quasipotential equation are obtained. In the construction, use is made of the iteration-separation method generalized to the case of the scattering of particles with spin on potentials containing a spin-orbit interaction.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 75–81, October, 1976.     

Coulomb-hadronic interference with polarized protons at intermediate energies

The theory of Coulomb-hadronic interference for particles with spin is discussed. At intermediate energies it is favourable to introduce Bethe phases for each of the amplitudes. For proton-proton scattering the values of the Bethe phases as well as the magnitudes of other correction terms are estimated on the basis of amplitudes reconstructed from current phase shifts. Suitable parameterizations for observables are proposed.