1,017 research outputs found
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
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
Analytic calculation of field-strength correlators
Field correlators are expressed using background field formalism through the
gluelump Green's functions. The latter are obtained in the path integral and
Hamiltonian formalism. As a result behaviour of field correlators is obtained
at small and large distances both for perturbative and nonperturbative parts.
The latter decay exponentially at large distances and are finite at x=0, in
agreement with OPE and lattice data.Comment: 28 pages, no figures; new material added, misprints correcte
Dynamics of confined gluons
Propagation of gluons in the confining vacuum is studied in the framework of
the background perturbation theory, where nonperturbative background contains
confining correlators. Two settings of the problem are considered. In the first
the confined gluon is evolving in time together with static quark and antiquark
forming the one-gluon static hybrid. The hybrid spectrum is calculated in terms
of string tension and is in agreement with earlier analytic and lattice
calculations. In the second setting the confined gluon is exchanged between
quarks and the gluon Green's function is calculated, giving rise to the Coulomb
potential modified at large distances. The resulting screening radius of 0.5 fm
presents a serious problem when confronting with lattice and experimental data.
A possible solution of this discrepancy is discussed.Comment: 17 pages, no figures; v2: minor numerical changes in the tabl
RG solutions for \alpha_s at large N_c in d=3+1 QCD
Solutions of RG equations for and are found in
the class of meromorphic functions satisfying asymptotic conditions at large
(resp. small , and analyticity properties in the plane. The
resulting is finite in the Euclidean region and agrees well
at GeV with the .Comment: 11 pages, no figures, dedicated to the 70th birthday of Professor
Francesco Calogero, subm. to the Journal of Nonlinear Mathematical Physic
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