39,316 research outputs found
Regularization of the Coulomb scattering problem
Exact solutions of the Schr\"odinger equation for the Coulomb potential are
used in the scope of both stationary and time-dependent scattering theories in
order to find the parameters which define regularization of the Rutherford
cross-section when the scattering angle tends to zero but the distance r from
the center remains fixed. Angular distribution of the particles scattered in
the Coulomb field is investigated on the rather large but finite distance r
from the center. It is shown that the standard asymptotic representation of the
wave functions is not available in the case when small scattering angles are
considered. Unitary property of the scattering matrix is analyzed and the
"optical" theorem for this case is discussed. The total and transport
cross-sections for scattering of the particle by the Coulomb center proved to
be finite values and are calculated in the analytical form. It is shown that
the considered effects can be essential for the observed characteristics of the
transport processes in semiconductors which are defined by the electron and
hole scattering in the fields of the charged impurity centers.Comment: 20 pages, 6 figure
Elastic pbar-d scattering and total pbar-d cross sections
Elastic pbar-d scattering is studied within the Glauber theory based on the
single- and double pbar-N scattering mechanisms. The full spin dependence of
the elementary pbar-N scattering amplitudes is taken into account and both the
S- and D-wave components of the deuteron are considered. The treatment of the
spin dependence is done in a (properly modified) formalism developed recently
by Platonova and Kukulin for the pd -> pd scattering process. Predictions for
differential cross sections and the spin observables A_y^d, A_y^pbar, A_xx,
A_yy are presented for antiproton beam energies between 50 and 300 MeV, using
amplitudes generated from the Nbar-N interaction model developed by the Juelich
group. Total polarized cross sections are calculated utilizing the optical
theorem. The efficiency of the polarization buildup for antiprotons in a
storage ring is investigated.Comment: 14 pages, 15 figures; some comments added, figure added, signs of
some spin-dependent cross sections correcte
Forward antiproton-deuteron elastic scattering and total spin-dependent antiproton-deuteron cross sections at intermediate energies
Spin-dependent total pbar-d cross sections are considered using the optical
theorem. For this aim the full spin dependence of the forward pbar-d elastic
scattering amplitude is considered in a model independent way. The
single-scattering approximation is used to relate this amplitude to the
elementary amplitudes of pbar-p and pbar-n scattering and the deuteron form
factor. A formalism allowing to take into account Coulomb-nuclear interference
effects in polarized pbar-d cross sections is developed. Numerical calculations
for the polarized total pbar-d cross sections are performed at beam energies
20-300 MeV using the Nbar-N interaction models developed by the Julich group.
Double-scattering effects are estimated within the Glauber approach and found
to be in the order of 10-20%. Existing experimental data on differential pbar-d
cross sections are in good agreement with the performed Glauber calculations.
It is found that for the used Nbar-N models the total longitudinal and
transversal pbar-d cross sections are comparable in absolute value to those for
pbar-p scattering.Comment: 19 pages, 8 figures; typos in appendix removed, Section about
Coulomb-nuclear interference re-structured, figures improved; accepted for
publication in Phys. Rev.
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