3,845 research outputs found
Mass generation with adjoint fermions
The QCD-like gauge theory with adjoint fermions is considered in the field
correlator formalism and the total spectrum of mesons and glueballs is obtained
in agreement with available lattice data. A new state of a white fermion
appears, as a bound state of the adjoint fermion and gluon with the mass close
to that of glueball. It is shown, that the main features of spectra and
thermodynamics of adjoint fermions can be explained by this new bound state.Comment: 19 page
Nonperturbative equation of state of quark-gluon plasma. Applications
The vacuum-driven nonperturbative factors for quark and gluon Green's
functions are shown to define the nonperturbative dynamics of QGP in the
leading approximation. EoS obtained recently in the framework of this approach
is compared in detail with known lattice data for including ,
, . The basic role in the dynamics at
T\la 3T_c is played by the factors which are approximately equal to the
modulus of Polyakov line for quark and gluon . The
properties of are derived from field correlators and compared to lattice
data, in particular the Casimir scaling property follows in the Gaussian approximation
valid for small vacuum correlation lengths. Resulting curves for ,
, are in a reasonable agreement with
lattice data, the remaining difference points out to an effective attraction
among QGP constituents.Comment: 20 pages, 6 figure
Nonperturbative corrections to the quark self-energy
Nonperturbative self-energy of a bound quark is computed gauge-invariantly in
the framework of background perturbation theory. The resulting Delta m^2_q is
negative and is a universal function of string tension and current quark mass.
The shift of hadron mass squared, M^2, due to Delta m^2_q is negative, large
for light quarks, and solves the long-standing problem of Regge intercepts in
relativistic quark models.Comment: LaTeX2e, 13 pages, minor differences are don
Strong decays and dipion transitions of Upsilon(5S)
Dipion transitions of with are studied using
the Field Correlator Method, applied previously to dipion transitions with
The only two parameters of effective Lagrangian were fixed in that
earlier study, and total widths as well as pionless
decay widths and
were calculated and are in a reasonable agreement with
experiment. The experimental spectra for and (5,2) transitions
are well reproduced taking into account FSI in the .Comment: 16 pages, 6 figure
Heavy-light mesons spectrum from the nonperturbative QCD in the einbein field formalism
The spectrum of B and D mesons (including the low lying orbitally and
radially excited states) is calculated using the quark-antiquark Hamiltonian
derived from QCD in the einbein field formalism. Spin-spin and spin-orbit terms
due to the confinement and OGE interactions are taken into account as
perturbations. Results for the masses and splittings are confronted to the
experimental and recent lattice data and are demonstrated to be in a reasonable
agreement with both. We find that the orbital excitations with l=2 and l=3 for
D meson lie approximately in the same region as its first radial excitation
that might solve the mystery of the extremely narrow D(2637) state recently
claimed by DELPHI Collaboration.Comment: 9 pages, LaTeX2e, no figures, 3 tables, typos in formulae and one
reference correcte
Gluelump spectrum in the QCD string model
Spectrum of gluons in the adjoint source field is computed analytically using
the QCD string Hamiltonian, containing only one parameter - string tension,
fixed by meson and glueball spectrum. Spin splitting is shown to be small. A
good agreement is observed with spatially generated gluelump states measured on
the lattice. Important role of gluelumps defining the behaviour of
field-strength correlators is stressed and correspondence with earlier
computations of the latter is established.Comment: LaTeX, 18 pages, no figures, references and comments adde
Deconfinement transition for nonzero baryon density in the Field Correlator Method
Deconfinement phase transition due to disappearance of confining
colorelectric field correlators is described using nonperturbative equation of
state. The resulting transition temperature at any chemical
potential is expressed in terms of the change of gluonic condensate
and absolute value of Polyakov loop , known from
lattice and analytic data, and is in good agreement with lattice data for
GeV. E.g. GeV for
respectively.Comment: 8 pages, 1 figure, LaTeX2e; some typos correcte
Gauge--invariant field correlators in QCD at finite temperature
We study by numerical simulations on a lattice the behaviour of the
gauge--invariant two--point correlation functions of the gauge field strengths
across the deconfinement phase transition.Comment: 12 pages, LaTeX file, + 5 PS figures, uuencoded-tar-compresse
The matrix Hamiltonian for hadrons and the role of negative-energy components
The world-line (Fock-Feynman-Schwinger) representation is used for quarks in
arbitrary (vacuum and valence gluon) field to construct the relativistic
Hamiltonian. After averaging the Green's function of the white system
over gluon fields one obtains the relativistic Hamiltonian, which is matrix in
spin indices and contains both positive and negative quark energies. The role
of the latter is studied in the example of the heavy-light meson and the
standard einbein technic is extended to the case of the matrix Hamiltonian.
Comparison with the Dirac equation shows a good agreement of the results. For
arbitrary system the nondiagonal matrix Hamiltonian components are
calculated through hyperfine interaction terms. A general discussion of the
role of negative energy components is given in conclusion.Comment: 29 pages, no figure
Weyl-Titchmarsh type formula for Hermite operator with small perturbation
Small perturbations of the Jacobi matrix with weights \sqrt n and zero
diagonal are considered. A formula relating the asymptotics of polynomials of
the first kind to the spectral density is obtained, which is analogue of the
classical Weyl-Titchmarsh formula for the Schroedinger operator on the
half-line with summable potential. Additionally a base of generalized
eigenvectors for "free" Hermite operator is studied and asymptotics of
Plancherel-Rotach type are obtained
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