14,689 research outputs found
Nonlinearity of vacuum reggeons and exclusive diffractive production of vector mesons at HERA
The processes of exclusive photo- and electroproduction of vector mesons
(770), (1020) and (3096) at collision energies and transferred momenta squared are considered in
the framework of a phenomenological Regge-eikonal scheme with nonlinear Regge
trajectories in which their QCD asymptotic behavior is taken into account
explicitly. By comparison of available experimental data from ZEUS and H1
Collaborations with the model predictions it is demonstrated that corresponding
angular distributions and integrated cross-sections in the above-mentioned
kinematical range can be quantitatively described with use of two -even
vacuum Regge trajectories. These are the "soft" pomeron dominating the high
energy reactions without a hard scale and the "hard" pomeron giving an
essential contribution to photo- and electroproduction of heavy vector mesons
and deeply virtual electroproduction of light vector mesons.Comment: 25 pages, 12 figure
Z(3) Symmetric Dimensional Reduction of (2+1)D QCD
Here we present a candidate for a Z(3)-symmetric reduced action for the
description of the (2+1)D SU(3) gauge theoryComment: 2 pages, Statistical QCD pro
Maeda-Dadhich Solutions as Real Black Holes
A four-dimensional static Schwarzschild-like solution obtained in [3]-[6] in
the frames of the Einstein-Gauss-Bonnet gravity at the Kaluza-Klein split is
analyzed. The matter in these solutions is created by auxiliary dimensions. The
main goal of our work is to study physically sensible characteristics, which
could be observable. Study of the perturbed equations demonstrates their
stability under linear perturbations. The specific combinations of the
parameters, permitting to construct black hole-like objects with one or two
horizons or naked singularities are determined. Stable orbits of test particles
around these black holes are presented. We show the exotic thermodynamical
properties of the solution, when the Hawking evaporation law has the behavior
opposite to usual one in General Relativity
QCD with Adjoint Scalars in 2D: Properties in the Colourless Scalar Sector
We present a numerical study of an SU(3) gauged 2D model for adjoint scalar
fields, defined by dimensional reduction of pure gauge QCD in (2+1)D at high
temperature. In the symmetric phase of its global Z_2 symmetry, two colourless
boundstates, even and odd under Z_2, are identified. Their respective
contributions (poles) in correlation functions of local composite operators A_n
of degree n=2p and 2p+1 in the scalar fields (p=1,2) fulfill factorization. The
contributions of two particle states (cuts) are detected. Their size agrees
with estimates based on a meanfield-like decomposition of the p=2 operators
into polynomials in p=1 operators. No sizable signal in any A_n correlation can
be attributed to 1/n times a Debye screening length associated with n
elementary fields. These results are quantitatively consistent with the picture
of scalar ``matter'' fields confined within colourless boundstates whose
residual ``strong'' interactions are very weak.Comment: 27 pages, improved presentation of results and some references added,
as accepted by Nucl. Phys.
Gravireggeons and transplanckian scattering in models with one extra dimension
The inelastic scattering of the brane fields induced by -channel
gravireggeons exchanges in the RS model with a small curvature is
considered, and the imaginary part of the eikonal is analytically calculated.
It is demonstrated that the results can be obtained from the corresponding
formulae previously derived in the ADD model with one extra dimension of the
size by formal replacement . The inelastic
cross section for the scattering of ultra-high neutrino off the nucleon is
numerically estimated for the case TeV, where
is a reduced Planck scale in five warped dimensions.Comment: 17 pages, LaTeX2e, 3 eps figure
Screening Masses in Dimensionally Reduced (2+1)D Gauge Theory
We discuss the screening masses and residue factorisation of the SU(3) (2+1)D
theory in the dimensional reduction formalism. The phase structure of the
reduced model is also investigated.Comment: 3 pages, Lattice 2001(gaugetheories
The Schwarzschild black hole as a point particle
The description of a point mass in general relativity (GR) is given in the
framework of the field formulation of GR where all the dynamical fields,
including the gravitational field, are considered in a fixed background
spacetime. With the use of stationary (not static) coordinates non-singular at
the horizon, the Schwarzschild solution is presented as a point-like field
configuration in a whole background Minkowski space. The requirement of a
stable -causality stated recently in [J.B.Pitts and W.C.Schieve, Found.
Phys., v. 34, 211 (2004)] is used essentially as a criterion for testing
configurations.Comment: LATEX, 8 pages, no figure
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