International Journal of Modern Physics E

The neutron skin thickness is calculated for spherically symmetric even–even lead and tin isotopes, and $N=126$ and $N=82$ isotones, with known experimental masses. A relation correlating the neutron skin thickness with the asymmetry parameter is determined, which may be used to constrain the nuclear equation of state.

The nucleus can be considered a relativistic system, In particular, we focus on heavy nuclei with zero spin and utilize the relativistic core-cluster model to investigate their structure properties. A zero-spin nucleus is assumed to consist of a core and a cluster, core and cluster spins are zero. We will solve the Klein–Gordon equation, which is a relativistic equation optimized for studying zero-spin systems, with the new phenomenological potential. Then, we will calculate the binding energy and charge radius of the zero-spin heavy nuclei by employing the wave function obtained from the Klein–Gordon equation.

The experimentally available angular distributions (ADs) for ${}^{6,7}$Li and ${}^{20}$Ne ions elastically scattered from a ${}^{24}$Mg target are reanalyzed using various nuclear potentials based on phenomenological as well as microscopic approaches. The considered data are ${}^6\mathrm{\text{Li}}+{}^{24}\mathrm{\text{Mg}}$ ADs at $E_{\mathrm{\text{lab}}}=20$, 88 and 240MeV; ${}^7\mathrm{\text{Li}}+{}^{24}\mathrm{\text{Mg}}$ ADs at $E_{\mathrm{\text{lab}}}=20$, 34 and 88MeV; and ${}^{20}\mathrm{\text{Ne}}+{}^{24}\mathrm{\text{Mg}}$ ADs at $E_{\mathrm{\text{lab}}}=50$, 60, 80, 90 and 100MeV. Special emphasis is given on the ($d+\alpha$) and ($t+\alpha$) cluster structures of the ⁶Li and ⁷Li weakly bound projectiles, which appear at relatively low energies of $\sim 1.4737$ and 2.468MeV, respectively. Furthermore, the ${}^{20}$Ne stable nucleus is a candidate to reveal the $\alpha +{}^{16}$O cluster structure at an energy of 4.73MeV. These systems are analyzed within the framework of the cluster folding model by taking into consideration the aforementioned cluster nature of the ⁶Li, ⁷Li and ${}^{20}$Ne projectiles. The adopted approaches fairly reproduced the experimental ADs.

Neutron detection using gadolinium (Gd) and its prompt gamma-rays is vital because of the high cross-section of Gd on thermal neutrons, thereby leading to significant interest in neutron detection with Gd-converted or Gd-loaded detector. However, simultaneous detection of neutron and gamma-rays with a Gd-loaded scintillator has been given less attention. In this study, we explored the feasibility of the GdI₃:Ce detector for simultaneous detection with Monte Carlo N-Particle transport extended simulation. Furthermore, we examined the physical properties of Gd for application in the radiation field mixed with neutron and gamma-rays. Similarly, we simulated the geometry of the GdI₃:Ce scintillator and its spectra obtained under various conditions. The results showed that GdI₃:Ce with a thickness of 1cm is enough to absorb 90$\%$ of photons with energy under 81keV. A shorter source-to-detector distance and larger detector size were superior to detecting prompt gamma-rays emitted from neutron capture, not only the gamma-rays from isomeric transition (named as general gamma-ray in this paper). Ultimately, spectra taken with the Gd₃:Ce scintillator under the radiation field mixed with neutrons and gamma-ray showed gamma-ray peaks from both radio-isotopes and Gd$(n\gamma )$Gd reaction, indicating the feasibility of the application of simultaneous detection.

In this research, the alpha decay fine structure for odd–odd nuclei has been investigated considering the effects of incompressibility of nuclear matter density in the range of $83\le Z\le 92$. In our calculations, transitions from the parent nuclei’s ground state to the daughter nuclei’s excited states have been considered. In these calculations, the double-folding model with effective finite-range nucleon–nucleon interactions was used in the framework of BDM3Y1, CDM3Y2, CDM3Y4, CDM3Y6 and BDM3Y1 configurations to calculate alpha-daughter nucleus interaction. These different versions of nucleon–nucleon interaction apply values of 176MeV to 270MeV for the incompressibility term of nuclear matter in calculations. WKB approximation along with the Cluster formation model has been used to calculate partial half-lives and branching ratio. The results of these calculations regarding partial half-lives in the framework of CDM3Y6 ($K=252$MeV) interactions indicate a better agreement with the corresponding experimental data than density-dependent interactions. It has also shown that by decreasing the values of incompressibility, the partial half-lives increase compared to the experimental data.

Event-by-event (ebe) multiplicity fluctuations and correlations amongst the charged particles emitted in the forward–backward symmetric pseudorapidity ($\eta$) windows of varying widths and positions are investigated by analyzing the experimental data on ${}^{197}$Au–AgBr collisions at 11.6AGeV/$c$. The findings are compared with the predictions of relativistic transport model, urqmd and independent particle emission (or mixed event) model. It is observed that the fluctuations in ebe mean pseudorapidity values and those reflected from the fluctuations strength measure, $\mathrm{\Phi }$ are relatively higher as compared to those expected from the statistically independent particle emission model. The study of the variance, ${\sigma }_c^2$ of a suitably defined forward–backward asymmetry variable $C$ as a function of $\eta$ window width and position indicates the presence of strong short-range correlations, which might arise due to isotropic decay of cluster-like objects either in forward or backward $\eta$ region. Furthermore, analyses of events having ring-like and jet-like substructures, carried out separately, suggest that the major contribution to the observed fluctuations in the data sample are due to ring-like events, while the contributions from the jet-like events appear to be rather small. The observed difference in the behavior of correlation strengths from the two types of events might be due to the enhanced emission of Cherenkov gluons, giving rise to the ring-like substructure. The mixed event analysis further confirms that the observed fluctuations are the distinct feature of the data, which disappear after event mixing.

In this work, the nuclear electromagnetic moments for the ground and low-lying excited states for sd shell nuclei have been calculated, resulting in a revised database with 56 magnetic dipole moments and 41 electric quadrupole moments. The shell model calculations are performed for each sd isotope chain, considering the sensitivity of changing the sd two-body effective interactions USDA, USDE, CWH and HBMUSD in the calculation of the one-body transition density matrix elements. The calculations incorporate the single-particle wave functions of the Skyrme interaction to generate a one-body potential in Hartree–Fock theory to calculate the single-particle matrix elements. For most sd shell nuclei, the experimental data are well reproduced, except for those spans near the island of inversion. In order to interpret the structure of low-lying excited states, the electric quadrupole and magnetic dipole transition form factors and the corresponding reduced transition probabilities in the sd shell nuclei have also been calculated, for which the experimental data are available. The present results demonstrate the nuclear electromagnetic moments’ sensitivity to many forms of the understanding of nucleon–nucleon interactions and provide a crucial baseline for future improvements in conceptual calculations.