International Journal of Modern Physics E

The survey of cluster models used for the description of the properties of nuclei was carried out. The interaction of intermediate protons with various odd and even nuclei is reviewed. The influence of the clusterization effects on the behavior of the elastic and inelastic scattering observables are demonstrated by using multiple diffraction scattering theory (MDST) and the α-cluster model with dispersion. The comparison of the calculations, based on two- and four-nucleon correlation models, have been performed. The elastic scattering of light nuclei from α-cluster nuclei is analyzed. The results given in this review suggest that the MDST variants based on cluster models seem to be rather attractive as compared with those based on the single-nucleon approximation. Such approaches, considering nucleon and light-nuclei scattering on α-clusters, are among the best examples of using Glauber's MDST, since they automatically include the internal nucleon–nucleon correlations both in the incident and target nuclei. Besides, α-clusters have zero spin and, in this case, the scattering amplitude does not involve explicit consideration of spin–spin effects. Moreover, these models often permit an accurate analytical calculation of the MDST series.

We suggest the diffuse approach to the relaxation processes within the kinetic theory for the Wigner distribution function. The diffusion and drift coefficients are evaluated taking into consideration the interparticle collisions on the distorted Fermi surface. Using the finite range interaction, we show that the momentum dependence of the diffuse coefficient D_p(p) has a maximum at Fermi momentum p = p_F whereas the drift coefficient K_p(p) is negative and reaches a minimum at p ≈ p_F. For a cold Fermi system the diffusion coefficient takes the nonzero value which is caused by the relaxation on the distorted Fermi surface at temperature T = 0. The numerical solution of the diffusion equation was performed for the particle-hole excitation in a nucleus with A = 16. The evaluated relaxation time τ_r ≈ 8.3 ⋅ 10^-23s is close to the corresponding result in a nuclear Fermi-liquid obtained within the kinetic theory.

Though the concept of a dark energy driven accelerating universe was introduced by the author in 1997, to date dark energy itself, as described below has remained a paradigm. We quickly review these and find a second cosmological signature of the 1997 model, consistent with latest observations.

In the mean-field approximation, we have studied the soliton which is embedded in a thermal medium within the chiral soliton model. The energy of the soliton or the baryon mass in the thermal medium has been carefully evaluated, in which we emphasize that the thermal effective potential in the soliton energy should be properly treated in order to derive a finite and well-defined baryon mass out of the thermal background. The result of the baryon mass at finite temperatures and densities in chiral soliton model are clearly presented.

The ejection of particles with energy up to 20 MeV u^-1 was reported previously from laser-induced processes in ultra-dense deuterium D(0). Studies of the kinetics of particle formation and decay, and of particle penetration through thick plates are now reported. Magnetic deflection is used to remove charged particles like electrons formed at the target. The signals at a collector in the beam at 0.9 m distance and a shadowed loop collector behind a 1.5–4.5 mm thick steel plate at 0.6 m are compared. The signal at the distant collector matches an intermediate particle B in a decay chain A → B → C with formation and decay time constants of 5–15 ns. The signal at the loop collector is delayed relative to the more distant collector, thus showing a delay of the particles penetrating through the steel plate. The signal at this collector is due to pair production with charge cancellation. Compton electrons from gamma radiation are observed at peak current densities of 1 mA cm^-2 at the distant collector.

Elliptic flow parameter, v₂ is considered as a sensitive probe for early dynamics of the heavy-ion collision. In this work, we have discussed the effect of detector efficiency, procedure of centrality determination, effect of resonance decay and the procedure to correct event plane resolution on the measured v₂ by standard event plane method within the framework of a transport model. The measured value of v₂ depends on the efficiency in particle number counting by the detector. The effect of centrality determination is found to be negligible. The new method of event plane resolution correction for wide centrality bin yields results in v₂ values closer to the true value of the v₂. The contributions from the resonance decay seems to decrease the value of v₂ of π and K within the Ultra relativistic Quantum Molecular Dynamics (UrQMD) model based calculation. We also propose a procedure to correct for an event bias effect on v₂ arising while comparing the minimum bias collision centrality v₂ values for different multi-strange hadrons. Finally, we have presented a model based confirmation of the recently proposed relation between v₂ obtained using event plane method and scalar product method to the true value of v₂.

We study the bulk properties such as binding energy (BE), root-mean-square (RMS) charge radius, quadrupole deformation etc. for Francium (Fr) isotopes having mass number A = 180–240 within the framework of relativistic mean field (RMF) theory. Systematic comparisons are made between the calculated results from RMF theory, Finite Range Droplet Model (FRDM) and the experimental data. Most of the nuclei in the isotopic chain shows prolate configuration in their ground state. The α-decay properties like α-decay energy and the decay half-life are also estimated for three different chains of ¹⁹⁸Fr, ¹⁹⁹Fr and ²⁰⁰Fr. The calculation for the decay half-life are carried out by taking two different empirical formulae and the results are compared with the experimental data.

Folding potentials of the elastic scattering drip-line nuclei at various incident energies is one method to study nuclear matter density distributions and nuclear radii. The nuclei with density distributions consisting of a bulk (core) and an outer layer (halo), dilute and spatially extended are called the halo nuclei caused for the weak particle binding. Several halo nuclei are studied and many potential candidates are identified. All the cross-sections of the elastic scattering for the drip-line nuclei ¹¹Be and ⁶He, are calculated to understand the exotic properties of these nuclei starting from its structure, extended radius, nuclear size till the large total reaction cross-sections for these nuclei when it interact with a stable target ¹²C.

In this paper, we study the mass spectrum and decay constants of ground state (1S) and radially excited states (2S and 3S) of heavy equal mass pseudoscalar mesons, η_c and η_b. We have employed the framework of Bethe–Salpeter equation (BSE) under Covariant Instantaneous Ansatz (CIA). Our predictions are in reasonable agreement with the data on available states and results of other models.

The scattering of spin-1 bosons in a nonminimal vector double-step potential is described in terms of eigenstates of the helicity operator and it is shown that the transmission coefficient is insensitive to the choice of the polarization of the incident beam. Poles of the transmission amplitude reveal the existence of a two-fold degenerate spectrum. The results are interpreted in terms of solutions of two coupled effective Schrödinger equations for a finite square well with additional δ-functions situated at the borders.