421 research outputs found
Two fermion relativistic bound states
We consider the relativistic quantum mechanics of a two interacting fermions
system. We first present a covariant formulation of the kinematics of the
problem and give a short outline of the classical results. We then quantize the
system with a general interaction potential and deduce the explicit equations
in a spherical basis. The case of the Coulomb interaction is studied in detail
by numerical methods, solving the eigenvalue problem for J=0, J=1, J=2 and
determining the spectral curves for a varying ratio of the mass of the
interacting particles. Details of the computations, together with a
perturbative approach in the mass ratio and an extended description of the
ground states of the Para- and Orthopositronium are given in Appendix.Comment: 26 pages, 6 figure
Unified covariant treatment of hyperfine splitting for heavy and light mesons
This paper aims at proving the fundamental role of a relativistic formulation
for quarkonia models.
We present a completely covariant description of a two-quark system
interacting by the Cornell potential with a Breit term describing the hyperfine
splitting. Using an appropriate procedure to calculate the Breit correction, we
find heavy meson masses in excellent agreement with experimental data.
Moreover, also when applied to light quarks and even taking average values of
the running coupling constant, we prove that covariance properties and
hyperfine splitting are sufficient to explain the light mesons spectrum and to
give a very good agreement with the data.Comment: 4 page
Relativistic two-body calculation of -mesons radiative decays
This paper is a prosecution of a previous work where we presented a unified
two-fermion covariant scheme which produced very precise results for the masses
of light and heavy mesons. We extend the analysis to some radiative decays of
mesons and we
calculate their branching ratios and their widths. For most of them we can make
a comparison with experimental data finding a good agreement.For the decays for
which data are not available we compare ours with other recent theoretical
previsions.Comment: 7 pages, 1 figur
Systems Engineering Perspective of the Cruise Industry
The maturation of the cruise industry has led to increased competition which demands more efficient operations. Systems engineering, a discipline that studies complex organizations of material, people, and information, is traditionally only applied in the manufacturing sector; however, it can make significant contributions to service industries such as the cruise industry. The author describes this type of engineering, explores how it can be applied to the cruise industry, and presents two case studies demonstrating applications to the cruise industry luggage delivery process and the information technology help desk process. The results show that this approach can make the processes more productive and enhance profitability for the cruise lines
Exponential mapping for non semisimple quantum groups
The concept of universal T matrix, recently introduced by Fronsdal and
Galindo in the framework of quantum groups, is here discussed as a
generalization of the exponential mapping. New examples related to
inhomogeneous quantum groups of physical interest are developed, the duality
calculations are explicitly presented and it is found that in some cases the
universal T matrix, like for Lie groups, is expressed in terms of usual
exponential series.Comment: 12 page
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