28 research outputs found
Universal light quark mass dependence and heavy-light meson spectroscopy
Clean predictions are presented for all the spin-averaged heavy-light meson
spectroscopies. A new symmetry is identified wherein the energy eigenstates
have a universal dependence on both the light and heavy quark masses. This
universality is used in an efficient analysis of these mesons within the QCD
string/flux tube picture. Unique predictions for all the D, D_s, B, and B_s
type mesons in terms of just four measured quantities.Comment: REVTeX4, 6 pages, 9 eps figure
Reduction of the QCD string to a time component vector potential
We demonstrate the equivalence of the relativistic flux tube model of mesons
to a simple potential model in the regime of large radial excitation. We make
no restriction on the quark masses; either quark may have a zero or finite
mass. Our primary result shows that for fixed angular momentum and large radial
excitation, the flux tube/QCD string meson with a short-range Coulomb
interaction is described by a spinless Salpeter equation with a time component
vector potential V(r) = ar - k/r.Comment: RevTeX4, 10 pages, 3 eps figure
Nonperturbative QCD Vacuum Effects in Nonlocal Quark Dynamics
A straightforward calculation reveals the essentially nonlocal character of
the leading heavy interaction arising from nonperturbative gluon
field correlations in the model of a fluctuating QCD vacuum. In light of this
quarkonium spin splitting ratio predictions which have supported the scalar
confinement ansatz are reconsidered as a specific example of possible
consequences for spectroscopy.Comment: Latex, 9 page
Hadronic Regge Trajectories: Problems and Approaches
We scrutinized hadronic Regge trajectories in a framework of two different
models --- string and potential. Our results are compared with broad spectrum
of existing theoretical quark models and all experimental data from PDG98. It
was recognized that Regge trajectories for mesons and baryons are not straight
and parallel lines in general in the current resonance region both
experimentally and theoretically, but very often have appreciable curvature,
which is flavor-dependent. For a set of baryon Regge trajectories this fact is
well described in the considered potential model. The standard string models
predict linear trajectories at high angular momenta J with some form of
nonlinearity at low J.Comment: 15 pages, 9 figures, LaTe
Glueball spectrum and the Pomeron in the Wilson loop approach
Using a nonperturbative method based on asymptotic behaviour of Wilson loops
we calculate masses of glueballs and corresponding Regge-trajectories. The only
input is string tension fixed by meson Regge slope, while perturbative
contributions to spin splittings are defined by standard alpha_s values. The
masses of lowest glueball states are in a perfect agreement with lattice
results. The leading glueball trajectory which is associated with Pomeron is
discussed in details and its mixing with f and f' trajectories is taken into
account.Comment: LaTeX2e, 49 pages, 2 figure
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.
Characterisation of a novel glycosylated glutathione transferase of Onchocerca ochengi, closest relative of the human river blindness parasite.
Heavy Quarkonia: Wilson Area Law, Stochastic Vacuum Model and Dual QCD
The semirelativistic interaction in QCD can be simply expressed
in terms of the Wilson loop and its functional derivatives. In this approach we
present the potential up to order using the expressions for
the Wilson loop given by the Wilson Minimal Area Law (MAL), the Stochastic
Vacuum Model (SVM) and Dual QCD (DQCD). We confirm the original results given
in the different frameworks and obtain new contributions. In particular we
calculate up to order the complete velocity dependent potential in the
SVM. This allows us to show that the MAL model is entirely contained in the
SVM. We compare and discuss also the SVM and the DQCD potentials. It turns out
that in these two very different models the spin-orbit potentials show up the
same leading non-perturbative contributions and 1/r corrections in the
long-range limit.Comment: 29 pages, revtex, 1 figure(fig1.ps); replaced with the last version
that will appear in Phys. Rev. D (1March 1997); few misprints correcte