3,927 research outputs found
Deuteron Compton scattering and electromagnetic polarizabilities of the nucleon
Differential cross section of deuteron Compton scattering has been calculated
using the Bonn NN-potential, a consistent set of meson-exchange currents and
seagulls, and lowest- and higher-order electromagnetic polarizabilities of the
nucleon. Estimates of the polarizabilities of the neutron are obtained from
recent experimental data.Comment: 3 pages, 2 figures, Latex2e with ps fonts. Talk at the FB16
Conference, Taipei, March 6-10, 2000. To appear in proceeding
Structure of the -meson and diamagnetism of the nucleon
The structure of the meson and the diamagnetism of the nucleon are
shown to be topics which are closely related to each other. Arguments are found
that the meson couples to two photons via its non-strange
structure component. This ansatz leads to a quantitative explanation of the
-channel component of the difference of electromagnetic polarizabilities,
(\alpha-\beta)^t(\alpha-\beta)^t_{p,n}=(5\alpha_e g_{\pi MM})/(6\pi^2 m^2_\sigma
f_\pi)=15.310^{-4}{\rm fm}^3(\alpha-\beta)^t_p=15.1\pm 1.3(\alpha-\beta)^t_n=14.8\pm 2.7\pi\pi\sigma(\alpha-\beta)^t_{p,n}=14\pm 2$, what also is in agreement with
the experimental results.Comment: Contribution made by Martin Schumacher to the International Workshop
on the Physics of Excited Baryons, 12 - 15 Oct. 2005, Tallahasse, Florida US
Compton Scattering from the Deuteron and Extracted Neutron Polarizabilities
Differential cross sections for Compton scattering from the deuteron were
measured at MAX-lab for incident photon energies of 55 MeV and 66 MeV at
nominal laboratory angles of , , and . Tagged
photons were scattered from liquid deuterium and detected in three NaI
spectrometers. By comparing the data with theoretical calculations in the
framework of a one-boson-exchange potential model, the sum and difference of
the isospin-averaged nucleon polarizabilities, and (in units of fm),
have been determined. By combining the latter with the global-averaged value
for and using the predictions of the Baldin sum rule for
the sum of the nucleon polarizabilities, we have obtained values for the
neutron electric and magnetic polarizabilities of (total) (model) and (total) (model), respectively.Comment: 4 pages, 2 figures, revtex. The text is substantially revised. The
cross sections are slightly different due to improvements in the analysi
Deuteron Compton Scattering in Effective Field Theory: Spin-Dependent Cross Sections and Asymmetries
Polarized Compton scattering on the deuteron is studied in nuclear effective
field theory. A set of tensor structures is introduced to define 12 independent
Compton amplitudes. The scalar and vector amplitudes are calculated up to
in low-energy power counting. Significant
contribution to the vector amplitudes is found to come from the spin-orbit type
of relativistic corrections. A double-helicity dependent cross section
is calculated to the same
order, and the effect of the nucleon isoscalar spin-dependent polarizabilities
is found to be smaller than the effect of isoscalar spin-independent ones.
Contributions of spin-independent polarizabilities are investigated in various
asymmetries, one of which has as large as 12 (26) percent effect at the
center-of-mass photon energy 30 (50) MeV.Comment: 22 pages, 8 figures included, replaced with the version submitted to
PR
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