Search results for "Abstract algebra"
showing 10 items of 452 documents
Error analysis of nuclear mass fits
2008
We discuss the least-square and linear-regression methods, which are relevant for a reliable determination of good nuclear-mass-model parameter sets and their errors. In this perspective, we define exact and inaccurate models and point out differences in using the standard error analyses for them. As an illustration, we use simple analytic models for nuclear binding energies and study the validity and errors of models' parameters, and uncertainties of its mass predictions. In particular, we show explicitly the influence of mass-number dependent weights on uncertainties of liquid-drop global parameters.
QQ-onia package: a numerical solution to the Schrodinger radial equation for heavy quarkonium
2008
30 pages, 3 figures.-- ISI article identifier:000265158700009.-- ArXiv pre-print avaible at: http://arxiv.org/abs/0805.2704
Variational principles for the calculation of the response function
1983
Several variational principles for inclusive processes are presented and illustrated by simple examples. By choosing appropriate trial functions, the doorway-state, moment- and cumulant-expansion of the response functions are derived from them.
Solitons in Nonlinear Transmission Lines
1996
Although solitary waves and solitons were originally discovered in the context of water waves and lattice dynamics, consideration of these physical systems (which will be considered in Chaps.5 and 8) leads to calculations far too involved for pedagogical purposes. Thus, for an introduction to the soliton concept, we therefore consider simple wave propagation in electrical nonlinear transmission lines and electrical networks.
The zero-point energy for rotation
1978
The Gaussian overlap approach (GOA) becomes inappropriate for describing the rotation of weakly deformed systems. A modification is proposed which allows to maintain the GOA for small deformations. The zero-point energy subtraction, derived from it, provides a simple and reliable approximation for angular momentum projection. It becomes obvious, however, that the projection complicates the equations which determine the motion along the deformation path. These effects are studied in some simple models and the results are condensed into a simple interpolation formula for the total zero-point energy.
Field transformations and simple models illustrating the impossibility of measuring off-shell effects
1999
In the context of simple models illustrating field transformations in Lagrangian field theories we discuss the impossibility of measuring off-shell effects in nucleon-nucleon bremsstrahlung, Compton scattering, and related processes. To that end we introduce a simple phenomenological Lagrangian describing nucleon-nucleon bremsstrahlung and perform an appropriate change of variables leading to different off-shell behavior in the nucleon-nucleon amplitude as well as the photon-nucleon vertex. As a result we obtain a class of equivalent Lagrangians, generating identical S-matrix elements, of which the original Lagrangian is but one representative. We make use of this property in order to show …
Effective Boost and 'Point Form' Approach
2002
Triangle Feynman diagrams can be considered as describing form factors of states bound by a zero-range interaction. These form factors are calculated for scalar particles and compared to point-form and non-relativistic results. By examining the expressions of the complete calculation in different frames, we obtain an effective boost transformation which can be compared to the relativistic kinematical one underlying the present point-form calculations, as well as to the Galilean boost. The analytic expressions obtained in this simple model allow a qualitative check of certain results obtained in similar studies. In particular, a mismatch is pointed out between recent practical applications o…
Minimal flavour seesaw models
2009
26 pages, 8 figures.-- ArXiv pre-print available at: http://arxiv.org/abs/0906.1461
Generalized Parton Distributions, Analyticity and Crossing
2005
A simple procedure for the derivation of Generalized Parton Distributions (GPDs) is suggested. Factorization of the perturbative and non-perturbative parts of the scattering amplitude is not assumed. Instead, GPDs are related, in the first approximation, to the deeply virtual Compton scattering (DVCS) amplitude, the emphasis being on the construction of DVCS or meson production amplitudes with correct analytical properties in a wide range of the kinematical variables.
Neutrino induced coherent pion production off nuclei and the partial conservation of the axial current
2009
15 pages, 7 figures, 1 table.-- PACS nrs.: 25.30.Pt; 12.15.-y; 13.15.+g.-- ArXiv pre-print available at: http://arxiv.org/abs/0903.5285