343 research outputs found
Extraction of the neutron charge form factor from the charge form factor of deuteron
We extract the neutron charge form factor from the charge form factor of
deuteron obtained from data at 1.717 (GeV). The
extraction is based on the relativistic impulse approximation in the instant
form of the relativistic Hamiltonian dynamics. Our results (12 new points) are
compatible with existing values of the neutron charge form factor of other
authors. We propose a fit for the whole set (35 points) taking into account the
data for the slope of the form factor at .Comment: LaTeX2e, 12 pages, 2 figures, tabl
Form Factors of Composite Systems by Generalized Wigner-Eckart Theorem for Poincar\'e group
The relativistic approach to electroweak properties of two-particle composite
systems developed previously is generalized here to the case of nonzero spin.
This approach is based on the instant form of relativistic Hamiltonian
dynamics. A special mathematical technique is used for the parametrization of
matrix elements of electroweak current operators in terms of form factors. The
parametrization is a realization of the generalized Wigner--Eckart theorem on
the Poincar\'e group, form factors are corresponding reduced matrix elements
and they have the sense of distributions (generalized functions). The
electroweak current matrix element satisfies the relativistic covariance
conditions and in the case of electromagnetic current it also automatically
satisfies the conservation law.Comment: Submitted to Theor. Math. Phy
Gardner's deformation of the Krasil'shchik-Kersten system
The classical problem of construction of Gardner's deformations for
infinite-dimensional completely integrable systems of evolutionary partial
differential equations (PDE) amounts essentially to finding the recurrence
relations between the integrals of motion. Using the correspondence between the
zero-curvature representations and Gardner deformations for PDE, we construct a
Gardner's deformation for the Krasil'shchik-Kersten system. For this, we
introduce the new nonlocal variables in such a way that the rules to
differentiate them are consistent by virtue of the equations at hand and
second, the full system of Krasil'shchik-Kersten's equations and the new rules
contains the Korteweg-de Vries equation and classical Gardner's deformation for
it.
PACS: 02.30.Ik, 02.30,Jr, 02.40.-k, 11.30.-jComment: 7th International workshop "Group analysis of differential equations
and integrable systems" (15-19 June 2014, Larnaca, Cyprus), 19 page
On the (non)removability of spectral parameters in -graded zero-curvature representations and its applications
We generalise to the -graded set-up a practical method for
inspecting the (non)removability of parameters in zero-curvature
representations for partial differential equations (PDEs) under the action of
smooth families of gauge transformations. We illustrate the generation and
elimination of parameters in the flat structures over -graded
PDEs by analysing the link between deformation of zero-curvature
representations via infinitesimal gauge transformations and, on the other hand,
propagation of linear coverings over PDEs using the Fr\"olicher--Nijenhuis
bracket.Comment: 38 pages, accepted to Acta Appl. Mat
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