2,242 research outputs found
Retardation effects in the rotating string model
A new method to study the retardation effects in mesons is presented.
Inspired from the covariant oscillator quark model, it is applied to the
rotating string model in which a non zero value is allowed for the relative
time between the quark and the antiquark. This approach leads to a retardation
term which behaves as a perturbation of the meson mass operator. It is shown
that this term preserves the Regge trajectories for light mesons, and that a
satisfactory agreement with the experimental data can be obtained if the quark
self-energy contribution is added. The consequences of the retardation on the
Coulomb interaction and the wave function are also analyzed.Comment: 4 figure
On two- and three-body descriptions of hybrid mesons
Hybrid mesons are exotic mesons in which the color field is not in its ground
state. Their understanding deserves interest from a theoretical point of view,
because it is intimately related to nonperturbative aspects of QCD. In this
work, we analyze and compare two different descriptions of hybrid mesons,
namely a two-body system with an excited string, or a three-body
system. In particular, we show that the constituent gluon approach
is equivalent to an effective excited string in the heavy hybrid sector.
Instead of a numerical resolution, we use the auxiliary field technique. It
allows to find simplified analytical mass spectra and wave functions, and still
leads to reliable qualitative predictions. We also investigate the light hybrid
sector, and found a mass for the lightest hybrid meson which is in satisfactory
agreement with lattice QCD and other effective models.Comment: 2 figure
A dilemma in representing observables in quantum mechanics
There are self-adjoint operators which determine both spectral and
semispectral measures. These measures have very different commutativity and
covariance properties. This fact poses a serious question on the physical
meaning of such a self-adjoint operator and its associated operator measures.Comment: 10 page
Pseudoscalar mesons and their radial excitations from the Effective Chiral Lagrangian
Effective Chiral Lagrangian is derived from QCD in the framework of Field
Correlator Method. It contains the effects of both confinement and chiral
symmetry breaking due to a special structure of the resulting quark mass
operator. It is shown that this Lagrangian describes light pseudoscalar mesons,
and Gell-Mann-Oakes-Renner relations for pions, eta and K mesons are
reproduced. Spectrum of radial excitations of pions and K mesons is found and
compared to experimentally known masses.Comment: 6 pages; v3: minor corrections, references adde
Preparing for the Improbable: Safety Incentives and the Price-Anderson Act
The Price-Anderson Act requires commercial nuclear power plants to maintain (approximately) $660 million in off-site accident coverage through two forms of insurance: market-provided private insurance and self-insurance in the form of retrospective assessments of reactor owners. We examine how changes in retrospective assessments influence the safety incentives of nuclear reactor owners. As one would expect, increases in self-insurance premiums increase the incentive to install safety systems more quickly. However, a more important conclusion is that self-insurance premiums as a function of reactor riskiness, rather than equal payments by reactor owners, yield a higher level of safety than under the current law
The Pegg-Barnett Formalism and Covariant Phase Observables
We compare the Pegg-Barnett (PB) formalism with the covariant phase
observable approach to the problem of quantum phase and show that PB-formalism
gives essentially the same results as the canonical (covariant) phase
observable. We also show that PB-formalism can be extended to cover all
covariant phase observables including the covariant phase observable arising
from the angle margin of the Husimi Q-function.Comment: 10 page
Collective modes and correlations in one-component plasmas
The static and time-dependent potential and surface charge correlations in a
plasma with a boundary are computed for different shapes of the boundary. The
case of a spheroidal or spherical one-component plasma is studied in detail
because experimental results are available for such systems. Also, since there
is some knowlegde both experimental and theoretical about the electrostatic
collective modes of these plasmas, the time-dependent correlations are computed
using a method involving these modes.Comment: 20 pages, plain TeX, submitted to Phys. Rev.
Static potential in baryon
The baryon static potential is calculated in the framework of field
correlator method and is shown to match the recent lattice results. The effects
of the nonzero value of the gluon correlation length are emphasized.Comment: 7 pages, 4 figures, talk at the NPD-2002 Conference, December 2-6,
ITEP, Mosco
Decay constants of the heavy-light mesons from the field correlator method
Meson Green's functions and decay constants in different
channels are calculated using the Field Correlator Method. Both,
spectrum and , appear to be expressed only through universal
constants: the string tension , , and the pole quark masses.
For the -wave states the calculated masses agree with the experimental
numbers within MeV. For the and mesons the values of are equal to 210(10) and 260(10) MeV, respectively, and their ratio
=1.24(3) agrees with recent CLEO experiment. The values MeV are obtained for the , , and mesons
with the ratio =1.19(2) and =1.14(2). The decay constants
for the first radial excitations as well as the decay constants
in the vector channel are also calculated. The difference of
about 20% between and , and directly follows
from our analytical formulas.Comment: 37 pages, 10 tables, RevTeX
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