12114990
Pion Observables in the Extended NJL Model with Vector and Axial-Vector Mesons☆
Abstract The momentum-space bosonization method of a Nambu and Jona-Lasinio type model with vector and axial-vector mesons is applied to ππ scattering. Unlike the case in earlier published papers, we obtain the ππ scattering amplitude using the linear and nonlinear realizations of chiral symmetry and fully taking into account the momentum dependence of meson vertices. We show the full physical equivalence between these two approaches. The chiral expansion procedure in this model is discussed in detail. Chiral expansions of the quark mass, pion mass and constant f π are obtained. The low-energy ππ phase shifts are compared to the available data. We also study the scalar form factor of the pion.
182432079
SPECTRALITY OF GELL-MANN-LOW FUNCTION
117509698
QCD NUCLEON MODEL WITH RELATIVISTIC OSCILLATOR INTERACTION BETWEEN CONSTITUENT QUARK
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.
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.
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.
119204441
Color path-integral Monte Carlo simulations of quark–gluon plasma
Abstract Thermodynamic properties of a strongly coupled quark–gluon plasma (QGP) of constituent quasiparticles are studied by a color path-integral Monte Carlo simulations (CPIMC). For our simulations we have presented QGP partition function in the form of color path integral with new relativistic measure instead of Gaussian one used in Feynman and Wiener path integrals. For integration over color variable we have also developed procedure of sampling color variables according to the group SU(3) Haar measure. It is shown that this method is able to reproduce the available quantum lattice chromodynamics (QCD) data.
8806503
Dynamics of resonances in strongly interacting systems
The effects of the propagation of particles which have a finite life-time and an according broad distribution in their mass spectrum are discussed in the context of a transport descriptions. In the first part some example cases of mesonic modes in nuclear matter at finite densities and temperatures are presented. These equilibrium calculations illustrate the dynamical range of spectral distributions to be adequately covered by non-equilibrium description of the dynamics of two nuclei colliding at high energies. The second part addresses the problem of transport descriptions which properly account for the damping width of the particles. A systematic and general gradient approximation is presented in the form of diagrammatic rules which permit to derive a self-consistent transport scheme from the Kadanoff-Baym equation. The scheme is conserving and thermodynamically consistent provided the self-energies are obtained within the phi-derivable two-particle irreducible (2PI) method of Baym. The merits, the limitations and partial cures of the limitations of this transport scheme are discussed in detail.
115321070
On the relationship between Boltzmann-Langevin and Boltzmann-Uehling-Uhlenbeck models
120068071
Partial-transparency effects in heavy-ion collisions at energies of the order of 1 GeV/nucleon
Abstract A model of heavy-ion collisions at energies E lab ∼ 1 GeV/nucleon taking into account the effects of incomplete statistical equilibrium in highly-excited nuclear matter is presented. The collision process is considered as the interaction of two flows of nucleons decelerating each other. This process is described within the framework of a relativistic kinetic approach employing the Fokker-Planck approximation. Assuming two-flow nonequilibrium the momentum distribution function is represented as a sum of two maxwellian distributions displaced by the average relative velocity of flows. Equations for time evolution of space-averaged velocities and internal energies of flows are derived. These equations contain a single model parameter, i.e. the effective deceleration length λ d . Using the firestreak model geometry inclusive cross sections of protons and composite particles (d, t) in the reactions Ne + NaF, Ar + KCl and Ar + Pb are calculated at various values of E lab . In contrast to the firestreak model, a complete stopping of colliding tubes in the centre-of-mass frame was not assumed in the present calculation. Composite particle spectra are calculated on the basis of the coalescence model. The theory is thoroughly compared with the experimental data. The approach suggested allows us to reproduce a two-humped structure in the rapidity distributions of the secondary particles. The experimental data analysis leads to the value λ d = 8 fm for E lab = 0.8 GeV/nucleon, which is in good agreement with the estimation based on experimental NN cross sections.
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