4,139 research outputs found
Confining strings in the Abelian-projected SU(3)-gluodynamics II. 4D-case with -term
The generalization of 4D confining string theory to the SU(3)-inspired case
is derived. It describes string representation of the Wilson loop in the
SU(3)-analogue of compact QED extended by the -term. It is shown that
although the obtained theory of confining strings differs from that of compact
QED, their low-energy limits have the same functional form. This fact leads to
the appearance of the string -term in the low-energy limit of the
SU(3)-inspired confining string theory. In particular, it is shown that in the
extreme strong coupling regime, the crumpling of string world sheets could
disappear owing to the string -term at . Finally, some
characteristic features of the SU(N)-case are pointed out.Comment: 8 pages, LaTeX2e, no figures, to appear in Europhys. Letter
Confining Strings in the Abelian-Projected SU(3)-Gluodynamics
String representation of the Wilson loop in 3D Abelian-projected
SU(3)-gluodynamics is constructed in the approximation that Abelian-projected
monopoles form a gas. Such an assumption is much weaker than the standard one,
demanding the monopole condensation. It is demonstrated that the summation over
world sheets, bounded by the contour of the Wilson loop, is realized by the
summation over branches of a certain effective multivalued potential of the
monopole densities. Finally, by virtue of the so-constructed representation of
the Wilson loop in terms of the monopole densities, this quantity is evaluated
in the approximation of a dilute monopole gas, which makes confinement in the
model under study manifest.Comment: 7 pages, new results are adde
SUSY 3D Georgi-Glashow model at finite temperature
We study the finite-temperature properties of the supersymmetric version of
(2+1)D Georgi-Glashow model. As opposed to its nonsupersymmetric counterpart,
the parity symmetry in this theory at zero temperature is spontaneously broken
by the bilinear photino condensate. We find that as the temperature is raised,
the deconfinement and the parity restoration occur in this model at the same
point . The transition is continuous, but is not of the Ising
type as in nonsupersymmetric Georgi-Glashow model, but rather of the
Berezinsky-Kosterlitz-Thouless type as in -invariant spin model.Comment: 8 pages, LaTeX2e, no figure
String breaking in QCD: dual superconductor vs. stochastic vacuum model
Effects of dispersion of the chromoelectric field of the flux tube on the
string-breaking distance are studied. The leading-order correction is shown to
slightly diminish the result following from the Schwinger formula. Instead,
accounting for corrections of all orders might result, at certain values of the
Landau-Ginzburg parameter, in an increase of the string-breaking distance up to
one order of magnitude. An alternative formula for this distance is obtained
when produced pairs are treated as holes in a confining pellicle, which spans
over the contour of an external quark-antiquark pair. Generalizations of the
obtained results to the cases of small temperatures, as well as temperatures
close to the critical one are also discussed.Comment: 21 pages, no figures, uses JHEP3.cl
Curvature expansion for the background-induced gluodynamics string
Using cumulant expansion for an averaged Wilson loop we derive an action of
the gluodynamics string in the form of a series in powers of the correlation
length of the vacuum. In the lowest orders it contains the Nambu-Goto term and
the rigidity term with the coupling constants computed from the bilocal
correlator of gluonic fields. Some higher derivative corrections are
calculated.Comment: 10 page
Superscaling in Nuclei: A Search for Scaling Function Beyond the Relativistic Fermi Gas Model
We construct a scaling function for inclusive electron
scattering from nuclei within the Coherent Density Fluctuation Model (CDFM).
The latter is a natural extension to finite nuclei of the Relativistic Fermi
Gas (RFG) model within which the scaling variable was
introduced by Donnelly and collaborators. The calculations show that the
high-momentum components of the nucleon momentum distribution in the CDFM and
their similarity for different nuclei lead to quantitative description of the
superscaling in nuclei. The results are in good agreement with the experimental
data for different transfer momenta showing superscaling for negative values of
, including those smaller than -1.Comment: 16 pages, 5 figures, submitted for publication to Phys. Rev.
String Nature of Confinement in (Non-)Abelian Gauge Theories
Recent progress achieved in the solution of the problem of confinement in
various (non-)Abelian gauge theories by virtue of a derivation of their string
representation is reviewed. The theories under study include QCD within the
so-called Method of Field Correlators, QCD-inspired Abelian-projected theories,
and compact QED in three and four space-time dimensions. Various
nonperturbative properties of the vacua of the above mentioned theories are
discussed. The relevance of the Method of Field Correlators to the study of
confinement in Abelian models, allowing for an analytical description of this
phenomenon, is illustrated by an evaluation of field correlators in these
models.Comment: 100 pages, LaTeX2e, no figures, 1 table, based on the Ph.D. thesises
at the Humboldt University of Berlin (1999) (available under
http://dochost.rz.hu-berlin.de) and the Institute of Theoretical and
Experimental Physics, Moscow (2000), new results are included, extended with
respect to the journal versio
Superscaling and Neutral Current Quasielastic Neutrino-Nucleus Scattering beyond the Relativistic Fermi Gas Model
The superscaling analysis is extended to include quasielastic (QE) scattering
via the weak neutral current of neutrinos and antineutrinos from nuclei. The
scaling function obtained within the coherent density fluctuation model (used
previously in calculations of QE inclusive electron and charge-changing (CC)
neutrino scattering) is applied to neutral current neutrino and antineutrino
scattering with energies of 1 GeV from C with a proton and neutron
knockout (u-channel inclusive processes). The results are compared with those
obtained using the scaling function from the relativistic Fermi gas model and
the scaling function as determined from the superscaling analysis (SuSA) of QE
electron scattering.Comment: 10 pages, 6 figures, published in Phys. Rev.
Breaking of ergodicity and long relaxation times in systems with long-range interactions
The thermodynamic and dynamical properties of an Ising model with both short
range and long range, mean field like, interactions are studied within the
microcanonical ensemble. It is found that the relaxation time of
thermodynamically unstable states diverges logarithmically with system size.
This is in contrast with the case of short range interactions where this time
is finite. Moreover, at sufficiently low energies, gaps in the magnetization
interval may develop to which no microscopic configuration corresponds. As a
result, in local microcanonical dynamics the system cannot move across the gap,
leading to breaking of ergodicity even in finite systems. These are general
features of systems with long range interactions and are expected to be valid
even when the interaction is slowly decaying with distance.Comment: 4 pages, 5 figure
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