393 research outputs found
Structure Of Demand And Equilibrium In Oligopolistic Models With Piecewise Quadratic Cost Functions
In this paper, we consider an oligopolistic model with conjectures concerning the price variations depending upon the agents’ production increase or increase. By introducing the notion of an interior stable equilibrium, we analyze the behavior of groups of consumers with different consumption abilities. The proposed techniques allow us to make a qualitative description of dependence of the market price upon the active demand component
Vibrating the QCD string
The large distance behaviour of the adiabatic hybrid potentials is studied in
the framework of the QCD string model. The calculated spectra are shown to be
the result of interplay between potential-type longitudinal and string-type
transverse vibrations.Comment: LaTeX2e, 9 pages, 2 Postscript figures, final version to appear in
Yad.Fi
A Novel Mechanism of H^0 Di-baryon Production in Proton-Proton Interactions from Parton Based Gribov-Regge Theory
A novel mechanism of H^0 and strangelet production in hadronic interactions
within the Gribov-Regge approach is presented. In contrast to traditional
distillation approaches, here the production of multiple (strange) quark bags
does not require large baryon densities or a QGP. The production cross section
increases with center of mass energy. Rapidity and transverse momentum
distributions of the H^0 are predicted for pp collisions at E_lab = 160 AGeV
(SPS) and \sqrt s = 200 AGeV (RHIC). The predicted total H^0 multiplicities are
of order of the Omega-baryon yield and can be accessed by the NA49 and the STAR
experiments.Comment: 4 page
Spectroscopy of Baryons Containing Two Heavy Quarks in Nonperturbative Quark Dynamics
We have studied the three quark systems in an Effective Hamiltonian approach
in QCD. With only two parameters: the string tension sigma and the strong
coupling constant alpha_s we obtain a good description of the ground state
light and heavy baryons. The prediction of masses of the doubly heavy baryons
not discovered yet are also given. In particular, a mass of 3620 MeV for the
lightest (ccu) baryon is found by employing the hyperspherical formalism to the
three quark confining potential with the string junction.Comment: 8 pages, LaTe
QCD string and the Lorentz nature of confinement
We address the question of the Lorentz nature of the effective long-range
interquark interaction generated by the QCD string with quarks at the ends.
Studying the Dyson-Schwinger equation for a heavy-light quark-antiquark system,
we demonstrate explicitly how a Lorentz-scalar interaction appears in the
Diraclike equation for the light quark, as a consequence of chiral symmetry
breaking. We argue that the effective interquark interaction in the Hamiltonian
of the QCD string with quarks at the ends stems from this effective scalar
interaction.Comment: LaTeX2e, 5 pages, uses jetpl.cls (included), to appear in JETP Let
Ground-state baryons in nonperturbative quark dynamics
We review the results obtained in an Effective Hamiltonian (EH) approach for
the three-quark systems. The EH is derived starting from the Feynman--Schwinger
representation for the gauge-invariant Green function of the three quarks
propagating in the nonperturbative QCD vacuum and assuming the minimal area law
for the asymptotic of the Wilson loop. It furnishes the QCD consistent
framework within which to study baryons. The EH has the form of the
nonrelativistic three-quark Hamiltonian with the perturbative Coulomb-like and
nonperturbative string interactions and the specific mass term. After outlining
the approach, methods of calculations of the baryon eigenenergies and some
simple applications are explained in details. With only two parameters: the
string tension and the strong coupling constant
a unified quantitative description of the ground state light
and heavy baryons is achieved. The prediction of masses of the doubly heavy
baryons not discovered yet are also given. In particular, a mass of
for the lightest baryon is found by employing the hyperspherical
formalism to the three quark confining potential with the string junction.Comment: 25 pages, 4 figures included, LaTeX 2e; to be published in Phys.
Atom. Nuc
QCD string in light-light and heavy-light mesons
The spectra of light-light and heavy-light mesons are calculated within the
framework of the QCD string model, which is derived from QCD in the Wilson loop
approach. Special attention is payed to the proper string dynamics that allows
us to reproduce the straight-line Regge trajectories with the inverse slope
being 2\pi\sigma for light-light and twice as small for heavy-light mesons. We
use the model of the rotating QCD string with quarks at the ends to calculate
the masses of several light-light mesons lying on the lowest Regge trajectories
and compare them with the experimental data as well as with the predictions of
other models. The masses of several low-lying orbitally and radially excited
heavy--light states in the D, D_s, B, and B_s meson spectra are calculated in
the einbein (auxiliary) field approach, which has proven to be rather accurate
in various calculations for relativistic systems. The results for the spectra
are compared with the experimental and recent lattice data. It is demonstrated
that an account of the proper string dynamics encoded in the so-called string
correction to the interquark interaction leads to an extra negative
contribution to the masses of orbitally excited states that resolves the
problem of the identification of the D(2637) state recently claimed by the
DELPHI Collaboration. For the heavy-light system we extract the constants
\bar\Lambda, \lambda_1, and \lambda_2 used in Heavy Quark Effective Theory
(HQET) and find good agreement with the results of other approaches.Comment: RevTeX, 42 pages, 7 tables, 7 EPS figures, uses epsfig.sty, typos
corrected, to appear in Phys.Rev.
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