126372642
Logarithmic and Power Scaling Violation in Lepton Deep Inelastic Scattering. Data {QCD} Analysis
119138207
Lepton flavor violating photoleptonic effect
We study lepton flavor violating analogs of the photoelectric effect, with a final μ or T instead of an electron: γe → μ and γe → T. On the basis of the general parametrization of the matrix element of the electromagnetic current we estimate the upper limits for the cross sections and event rates of these processes, imposed by the current experimental bounds on μ → ey and T → eγ decays.
117509698
QCD NUCLEON MODEL WITH RELATIVISTIC OSCILLATOR INTERACTION BETWEEN CONSTITUENT QUARK
182432079
SPECTRALITY OF GELL-MANN-LOW FUNCTION
896237
Electroproduction of charmonia off nuclei
In a recent publication we have calculated elastic charmonium production in ep collisions employing realistic charmonia wave functions and dipole cross sections and have found good agreement with the data in a wide range of s and Q^2. Using the ingredients from those calculations we calculate exclusive electroproduction of charmonia off nuclei. Here new effects become important, (i) color filtering of the c-cbar pair on its trajectory through nuclear matter, (ii) dependence on the finite lifetime of the c-cbar fluctuation (coherence length) and (iii) gluon shadowing in a nucleus compared to the one in a nucleon. Total coherent and incoherent cross sections for C, Cu and Pb as functions of s and Q^2 are presented together with some differential cross sections. The results can be tested with future electron-nucleus colliders or in peripheral collisions of ultrarelativistic heavy ions.
118014393
QCD analysis of deep inelastic lepton-scattering data
We have carried out a QCD analysis of data on deep inelastic lepton-scattering (using data of the collaborations BCDMS, EMC, and CDHS) in the leading and next-to-leading orders in the coupling constant ..cap alpha../sub s/. We have considered the effect of the sea quarks and gluons. We discuss the dependence of our results for ..lambda.. on effects of twist corrections, nuclear target effects, and heavy-quark production thresholds.
117037776
Dynamical instabilities in hadron plasma:: Filamentation
Abstract In the framework of a relativistic kinetic model with mean σ- and ω-fields possible instabilities of hadron plasma are studied under the conditions arising in heavy nucleus collisions at energies of tens GeV/nucleon. A general dispersion equation is derived. It is shown that in a two-flux regime the filamentation mode resulting in the system stratification into separate current filaments turns out to be most unstable. Time scale estimates suggest that this instability should be expected in heavy nucleus collisions. A collective filamentation deceleration mechanism which can considerably increase the stopping power of nuclear matter is discussed. A method of detecting the filamentation instability by a characteristic angular distribution of hard electromagnetic radiation is proposed.
123021094
Analysis of intermediate-energy heavy-ion collisions within relativistic mean-field two-fluid model
A three-dimensional realization of the relativistic mean-field two-fluid model is described. First results of analyzing the inclusive data on the yield of nuclear fragments and pions, as well as the Plastic-Ball rapidity distributions of nuclear fragments are presented. For comparison, calculations within the conventional relativistic hydrodynamical model with the same mean fields are also performed. In spite of a pronounced sensitivity of the nuclear dynamics to the nuclear equation of state (more precisely, to the form of the mean fields), it is found that all the analyzed observables, except the pion spectra, appear to be fairly insensitive to it. The sensitivity to the nuclear stopping power is slightly higher. The original sensitivity of the rapidity distributions to the stopping power is smeared out by the Plastic-Ball filter and selection criterion. Nevertheless, one can conclude that the stopping power induced by the Cugnon parametrization of the nucleon-nucleon cross sections is not quite sufficient for a more adequate reproduction of the experimental data.
120525462
Stochastic multi-fluid models for intermediate-energy heavy-ion collisions☆
Abstract The relativistic Boltzmann-Langevin equation is reduced to a stochastic multi-fluid model and the corresponding transport coefficients, i.e. the interflow friction force and the interflow diffusion tensor, are extracted. The model is applied to fluctuation phenomena in the equilibration process for two counter-streaming nuclear fluids.
122934808
Relativistic mean field kinetic approach to hadron plasma and three-fluid dynamics
Abstract Proceeding from the Walecka mean field theory, a system of relativistic kinetic equations has been derived for the description of hadron plasma formation and evolution in nucleus-nucleus collisions at high energies. These equations comprise the dynamics of relativistic self-consistent σ and ω fields and, in particular, satisfactorily described ground states of nuclei. The constructed collision integrals are expressed via inclusive hadron-hadron cross sections and allow one to describe inelastic production of new particles in the process of the nucleus-nucleus collision. A method of solving these kinetic equations, based on a model representation of distribution functions, is proposed. An ansatz for the distribution functions is constructed proceeding from the assumption of incomplete stopping of nuclei in the collision process. This ansatz make it possible to reduce the set of kinetic equations to a set of equations of the three-fluid dynamics type for the parameters of the distribution functions.
18452734
What we have learned from 3-fluid hydrodynamics up to now
A possibility to interpret available data from AGS and SPS within purely hadronic scenario is analyzed. This is based on analysis of problems met in simulations of heavy-ion collisions within 3-fluid dynamics with purely hadronic equation of state. The only exception has been done for success of the model in reproduction of transverse-mass spectra of various hadrons, since the excitation functions of inverse slopes of kaon spectra are interpreted as an indication of a phase transition. In particular, we try to indicate those data which apparently require assumption of a phase transition into quark-gluon phase for their reproduction. What we have learned from 3-fluid hydrodynamics up to now