1,497 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
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
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
Diquark and triquark correlations in the deconfined phase of QCD
We use the non-perturbative Q\bar Q potential at finite temperatures derived
in the Field Correlator Method to obtain binding energies for the lowest
eigenstates in the Q\bar Q and QQQ systems (Q=c,b). The three--quark problem is
solved by the hyperspherical method. The solution provides an estimate of the
melting temperature and the radii for the different diquark and triquark bound
states. In particular we find that J/\psi and ground states survive up to
T \sim 1.3 T_c, where T_c is the critical temperature, while the corresponding
bottomonium states survive even up to higher temperature, T \sim 2.2 T_c.Comment: 11 pages, 1 figure; published versio
Analytic Methods in Nonperturbative QCD
Recently developed analytic methods in the framework of the Field Correlator
Method are reviewed in this series of four lectures and results of calculations
are compared to lattice data and experiment. Recent lattice data demonstrating
the Casimir scaling of static quark interaction strongly support the FCM and
leave very little space for all other theoretical models, e.g. instanton
gas/liquid model. Results of calculations for mesons, baryons, quark-gluon
plasma and phase transition temperature demonstrate that new analytic methods
are a powerful tool of nonperturbative QCD along with lattice simulations.Comment: LaTeX, 34 pages; Lectures given at the 13th Indian-Summer School
"Understanding the Structure of Hadrons", August 28 - September 1, 2000,
Prague, Czech Republi
Current correlators in QCD: OPE versus large distance dynamics
We analyse the structure of current-current correlators in coordinate space
in large limit when the corresponding spectral density takes the form of
an infinite sum over hadron poles. The latter are computed in the QCD string
model with quarks at the ends, including the lowest states, for all channels.
The corresponding correlators demonstrate reasonable qualitative agreement with
the lattice data without any additional fits. Different issues concerning the
structure of the short distance OPE are discussed.Comment: LaTeX, 25 pages, 13 figure
The static interaction at small distances and OPE violating terms
Nonperturbative contribution to the one-gluon exchange produces a universal
linear term in the static potential at small distances . Its role in the resolution of long--standing
discrepancies in the fine splitting of heavy quarkonia and improved agreement
with lattice data for static potentials is discussed, as well as implications
for OPE violating terms in other processes.Comment: Latex, 5 pages, to be published in JETP Let
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