Multi-particle Production and Thermalization in High-Energy QCD

We argue that multi-particle production in high energy hadron and nuclear collisions can be considered as proceeding through the production of gluons in the background classical field. In this approach we derive the gluon spectrum immediately after the collision and find that at high energies it is parametrically enhanced by ln(1/x) with respect to the quasi-classical result (x is the Bjorken variable). We show that the produced gluon spectrum becomes thermal (in three dimensions) with an effective temperature determined by the saturation momentum Qs, T= c Qs/2pi during the time ~1/T; we estimate c=sqrt{2pi}/2 ~ 1.2. Although this result by itself does not imply that the gluon spectrum will remain thermal at later times, it has an interesting applications to heavy ion collisions. In particular, we discuss the possibility of Bose-Einstein condensation of the produced gluon pairs and estimate the viscosity of the produced gluon system.Comment: 25 pages, 4 figures; typos fixed; discussions expanded; we added a new section IV in which we argue that at high energies the production mechanism discussed in the paper is parametrically enhanced by ln(1/x) with respect to the quasi-classical resul

New Outlook on the Possible Existence of Superheavy Elements in Nature

A consistent interpretation is given to some previously unexplained phenomena seen in nature in terms of the recently discovered long-lived high spin super- and hyper-deformed isomeric states. The Po halos seen in mica are interpreted as due to the existence of such isomeric states in corresponding Po or nearby nuclei which eventually decay by gamma- or beta-decay to the ground states of 210Po, 214Po and 218Po nuclei. The low-energy 4.5 MeV alpha-particle group observed in several minerals is interpreted as due to a very enhanced alpha transition from the third minimum of the potential-energy surface in a superheavy nucleus with atomic number Z=108 (Hs) and atomic mass number around 271 to the corresponding minimum in the daughter.Comment: 8 pages, 8 figures, 5 tables. Paper presented at VII Int. School-Seminar on Heavy Ion Physics, May 27 - June 1, 2002, Dubna, Russi

Pair creation in transport equations using the equal-time Wigner function

Based on the equal-time Wigner function for the Klein-Gordon field, we discuss analytically the mechanism of pair creation in a classical electromagnetic field including back-reaction. It is shown that the equations of motion for the Wigner function can be reduced to a variable-frequency oscillator. The pair-creation rate results then from a calculation analogous to barrier penetration in nonrelativistic quantum mechanics. The Wigner function allows one to utilize this treatment for the formulation of an effective transport theory for the back-reaction problem with a pair-creation source term including Bose enhancement.Comment: 19 pages, LaTeX, UFTP 316/199

Exact Evolution Operator on Non-compact Group Manifolds

Free quantal motion on group manifolds is considered. The Hamiltonian is given by the Laplace -- Beltrami operator on the group manifold, and the purpose is to get the (Feynman's) evolution kernel. The spectral expansion, which produced a series of the representation characters for the evolution kernel in the compact case, does not exist for non-compact group, where the spectrum is not bounded. In this work real analytical groups are investigated, some of which are of interest for physics. An integral representation for the evolution operator is obtained in terms of the Green function, i.e. the solution to the Helmholz equation on the group manifold. The alternative series expressions for the evolution operator are reconstructed from the same integral representation, the spectral expansion (when exists) and the sum over classical paths. For non-compact groups, the latter can be interpreted as the (exact) semi-classical approximation, like in the compact case. The explicit form of the evolution operator is obtained for a number of non-compact groups.Comment: 32 pages, 5 postscript figures, LaTe

INTRAMURAL VESSELS, ACID MUCOPOLYSACCHARIDES AND LIPIDES IN THE WALL OF AORTA ABDOMINALIS AND ITS VISCERAL BRANCHES

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STRUCTURE AND VACSULARIZATION OF THE VENA CAVA INFERIOR WALL IN MAN

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Super- and Hyperdeformed Isomeric States and Long-Lived Superheavy Elements

The recent discoveries of the long-lived high spin super- and hyperdeformed isomeric states and their unusual radioactive decay properties are described. Based on their existence a consistent interpretation is given to the production of the long-lived superheavy element with Z = 112, via secondary reactions in CERN W targets, and to the low energy and very enhanced alpha-particle groups seen in various actinide fractions separated from the same W target. In addition, consistent interpretations are suggested for previously unexplained phenomena seen in nature. These are the Po halos, the low-energy enhanced 4.5 MeV alpha-particle group proposed to be due to an isotope of a superheavy element with Z = 108, and the giant halos.Comment: 4 pages. Contribution to the 2nd Int. Conf. on the Chemistry and Physics of the Transactinide Elements (TAN 03) Napa California, November 200

VASCULARIZATION OF THE WALL OF THE VISCERAL AFFLUENT BRANCHES OF VENA CAVA INFERIOR IN MAN

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Pair production by boost-invariant fields in comoving coordinates

We derive the pair-production probability in a constant electric field in Rindler coordinates in a quasi-classical approximation. Our result is different from the pair-production probability in an inertial frame (Schwinger formula). In particular, it exhibits non-trivial dependence on rapidity and deviation from Gaussian behavior at small transverse momenta. Our results can be important for analysis of particle production in heavy-ion collisions.Comment: 12 pages, 2 figures. Discussion added and typos fixe

Damping of electromagnetic waves due to electron-positron pair production

The problem of the backreaction during the process of electron-positron pair production by a circularly polarized electromagnetic wave propagating in a plasma is investigated. A model based on the relativistic Boltzmann-Vlasov equation with a source term corresponding to the Schwinger formula for the pair creation rate is used. The damping of the wave, the nonlinear up-shift of its frequency due to the plasma density increase and the effect of the damping on the wave polarization and on the background plasma acceleration are investigated as a function of the wave amplitude.Comment: 11 pages, 5 figures; revtex