International Journal of Modern Physics E

The theory of confinement and deconfinement is discussed as based on the properties of the QCD vacuum. The latter are described by field correlators of color-electric and color-magnetic fields in the vacuum, which can be calculated analytically and on the lattice. As a result one obtains a self-consistent theory of the confined region in the (μ, T) plane with realistic hadron properties. At the boundary of the confining region, the color-electric confining correlator vanishes, and the remaining correlators describe strong nonperturbative dynamics in the deconfined region with (weakly) bound states. Resulting equation of state for μ = 0, p(T), are in good agreement with lattice data. Phase transition occurs due to evaporation of a part of the color-electric gluon condensate, and the resulting critical temperatures T_c(μ) for different n_f are in good correspondence with available data.

The dynamical cluster-decay model (DCM), with deformations and orientation degrees of freedom of the incoming nuclei and of outging fragments included, is used to study the excitation functions of the "equatorial" compact hot fusion reaction ²⁴⁴Pu+⁴⁸Ca→²⁹²114^* (compact orientation angle θ_c=90° for ²⁴⁴Pu). Considering the higher multipole deformations up to hexadecapole deformation β₄ and configurations with "compact" orientation θ_c, the model is shown to give a good description of the measured individual light-particle decay channels σ_xn, here x=3, 4 and 5, and other decay channels, the fusion-fission σ_ff and quasi-fission σ_qf (equivalently, capture σ_cap) with in one parameter fitting, the neck length ΔR. The quasi-fission is also considered as a cold process with an elongated "polar" configuration. The xn-channel cross-sections for collisions between nuclei with static deformations at their respective compact orientations are shown to be much more than for the case of the nuclei taken to be spherical, signifying the increase in fusion threshold for an intermediate hot fusion reaction to be associated with the static deformation of the target nucleus and its orientation at the point of collision in its path toward the (spherical) compound nucleus. The shell effects in both the potential and kinetic energy (the mass parameters) terms of the Hamiltonian are shown to be important. The free parameter ΔR of the model is shown to depend strongly on limiting angular momentum, which in turn depends on the use of sticking or non-sticking moment of inertia for angular momentum effects. For the sticking moment of inertia, the evaporation residue (neutron emission) is shown to occur almost promptly (largest ΔR), followed by the competing (hot/cold) quasi-fission and ending finally with fusion-fission of hot compound nucleus. Different ΔR's (equivalently, relative separations) for the three processes means to predict that the processes ER, ff and qf happen in different time-scales, in agreement with the indications of experiments.

Evidence for the existence of long-lived isotopes with atomic mass numbers 261 and 265, and abundance of (1-10)×10^-10 relative to Au, has been found in a study of natural Au using inductively coupled plasma-sector field mass spectrometry. The measured masses match the predictions for the masses of ²⁶¹Rg and ²⁶⁵Rg(Z=111), and those of some isobars of nearby elements. Based on chemical arguments, it is proposed that they are most probably isotopes of Rg. It is deduced that long-lived isomeric states exist in these isotopes. The hypothesis that they belong to a new class of long-lived high spin super- and hyperdeformed isomeric states is discussed.

In this work, the analytical solution of the radial Schrödinger equation for the Woods–Saxon potential is presented. In our calculations, we have applied the Nikiforov–Uvarov method by using the Pekeris approximation to the centrifugal potential for arbitrary l states. The bound state energy eigenvalues and corresponding eigenfunctions are obtained for various values of n and l quantum numbers.

For the interactions of p, ³He, ⁴He, and ⁶Li with emulsion at 4.5 A GeV/c, an experimental study has been performed. The type of interactions chosen was central, which enables to analyze a specific interaction mechanism. The selection of the central events has been in the framework of the particles emitted beyond the kinematic limits (θ_Lab≥90°). This selection provides a strict criterion to distinguish the central collisions. For the sake of comparison, an additional criterion is introduced. It deals with interactions that exhibit an absence of projectile fragmentation. A detailed study of the emitted pions multiplicity is presented. The focusing is on the light emulsion target H and CNO in comparison with the heavy AgBr. The analysis reveals that the occultation of light projectile nuclei is possible in CNO targets along with the complete occultation in AgBr.

The nonrelativistic wave functions of ³H and ³He nuclei have been obtained on the basis of the experimentally measured charge form factors. The differential cross section of the elastic ³He-nucleus scattering has been calculated with the help of the wave function derived. This cross section agrees with the experimental data on the elastic scattering of ³He by ⁹⁰Zr, ¹²⁰Sn, and ²⁰⁸Pb nuclei at 130 and 217 MeV. The integrated cross sections of various processes of ³H and ³He interaction with heavy nuclei have also been calculated.

In order to determine the equation of state in the isospin asymmetrical nuclear interactions, we have found the observables for extracting the information of them within the isospin-dependent quantum molecular dynamics in recent years. The several sensitive probes for extracting the information of the in-medium nucleon–nucleon cross section and the symmetry potential have found; meanwhile, their mechanisms are investigated in more details. The main point in this paper gives the summary for above probes and their outlook in the future.

We prove that Nambu–Jona-Lasinio model is an exact description of infrared Quantum ChromoDynamics (QCD) deriving it from QCD Lagrangian. The model we obtain is renormalizable and confining but, taking very small momenta fixes completely all the parameters of the Nambu–Jona-Lasinio model through those of QCD. The choice of the infrared propagator is done consistently with recent numerical results from lattice and Dyson–Schwinger equations for Yang–Mills theory. The model we get coincides, once the ultraviolet contribution is removed, with the one proposed by Langfeld, Kettner and Reinhardt [Nucl. Phys. A608 (1996) 331].

It is shown that the use of a density-dependent effective Pauli potential together with a generic nucleon–nucleon interaction potential plays a crucial role to reproduce not only the binding energies but also the matter root mean square radii of medium mass range spin–isospin saturated nuclei. This study is performed with a semiclassical Monte Carlo many-body simulation within the context of a simplified nucleon–nucleon interaction to focus on the effect of the genuine correlations due to the fermionic nature of nucleons. The procedure obtained is rather robust and it does not depend on the detailed features of the nucleon–nucleon interaction. For nuclei below saturation the density dependence may be represented in terms either of the nucleon number, A, or the associated Fermi momenta. When testing the simulation procedure for idealized "infinite" symmetric nuclear matter within the corresponding range of densities, we find that, beyond the low particle number limit, finite size effects do not affect the Pauli potential strength parametrization.

The effect of muonic molecules complex forming with different spin states (J = 0, 1) in various decay channels on the cycling rate, the effective sticking coefficient, and the neutron yield per muon stopped in mixture was studied. It was shown that the error of the relative neutron yield is decreased in the optimum physical condition of the deuterium in the mixture by considering the effect of various decay channels of the muonic molecule complex.

The Breit interaction contains terms that are singular in nature and cannot be used non-perturbatively for quark–antiquark bound state studies. We regularize the Breit interaction by subtraction such that the interaction is not singular at the origin but the intermediate and long-range parts of the interaction remain unchanged. With the regularized quark–antiquark potential and the confining potential, the solution of bound states are therefore stable possessing wave functions that can be used for future applications in other study of scattering and reaction problems.