16 research outputs found
Multiple addition theorem for discrete and continuous nonlinear problems
The addition relation for the Riemann theta functions and for its limits,
which lead to the appearance of exponential functions in soliton type equations
is discussed. The presented form of addition property resolves itself to the
factorization of N-tuple product of the shifted functions and it seems to be
useful for analysis of soliton type continuous and discrete processes in the
N+1 space-time. A close relation with the natural generalization of bi- and
tri-linear operators into multiple linear operators concludes the paper.Comment: 9 page
Electroweak jet cascading in the decay of superheavy particles
We study decays of superheavy particles into leptons. We show that they
initiate cascades similar to QCD parton jets, if m_X\gsim 10^6 GeV.
Electroweak cascading is studied and the energy spectra of the produced leptons
are calculated in the framework of a broken SU(2) model of weak interactions.
As application, important for the Z-burst model for ultrahigh energy cosmic
rays, we consider decays of superheavy particles coupled on tree-level only to
neutrinos and derive stringent limit for these decays from the observed diffuse
extragalactic -ray flux.Comment: 4 pages, 1 eps figur
Duality for Exotic Bialgebras
In the classification of Hietarinta, three triangular
-matrices lead, via the FRT formalism, to matrix bialgebras which are not
deformations of the trivial one. In this paper, we find the bialgebras which
are in duality with these three exotic matrix bialgebras. We note that the
duality of FRT is not sufficient for the construction of the bialgebras
in duality. We find also the quantum planes corresponding to these bialgebras
both by the Wess-Zumino R-matrix method and by Manin's method.Comment: 25 pages, LaTeX2e, using packages: cite, amsfonts, amsmath, subeq
Color coherent phenomena on nuclei and the QCD evolution equation
We review the phenomenon of color coherence in quantum chromodynamics (QCD),
its implications for hard and soft processes with nuclei, and its experimental
manifestations. The relation of factorization theorems in QCD with color
coherence phenomena in deep inelastic scattering (DIS) and color coherence
phenomena in hard exclusive processes is emphasized. Analyzing numerically the
QCD evolution equation for conventional and skewed parton densities in nuclei,
we study the onset of generalized color transparency and nuclear shadowing of
the sea quark and gluon distributions in nuclei as well as related phenomena.
Such novel results as the dependence of the effective coherence length on
and general trends of the QCD evolution are discussed. The limits of the
applicability of the QCD evolution equation at small Bjorken are estimated
by comparing the inelastic quark-antiquark- and two gluon-nucleon (nucleus)
cross sections, calculated within the DGLAP approximation, with the dynamical
boundaries, which follow from the unitarity of the matrix for purely QCD
interactions. We also demonstrate that principles of color coherence play an
important role in the processes of soft diffraction off nuclei.Comment: 58 pages, 19 figures, Revtex. Minor editor's changes, final version
published in J.Phys. G27 (2001) R23-6
Ultra-High Energy Neutrino Fluxes: New Constraints and Implications
We apply new upper limits on neutrino fluxes and the diffuse extragalactic
component of the GeV gamma-ray flux to various scenarios for ultra high energy
cosmic rays and neutrinos. As a result we find that extra-galactic top-down
sources can not contribute significantly to the observed flux of highest energy
cosmic rays. The Z-burst mechanism where ultra-high energy neutrinos produce
cosmic rays via interactions with relic neutrinos is practically ruled out if
cosmological limits on neutrino mass and clustering apply.Comment: 10 revtex pages, 9 postscript figure