International Journal of Modern Physics E

We have investigated the threshold anomaly observed in ⁷Li + ${}^{208}$Pb nuclear system by analyzing the available ⁷Li+${}^{208}$Pb experimental angular distribution measurements. The experimental data for the weakly bound ⁷Li ions elastically scattered from ${}^{208}$Pb target at 13 energy sets ranging from 25.67 and up to 68MeV are subjected to detailed analysis using different interaction potentials created either based on phenomenological, semimicroscopic and microscopic models. The loosely bound nucleus ⁷Li, possessing a predominant $\alpha +t$ cluster structure at 2.468MeV, is a good candidate as its break-up reaction studies would help to understand the break-up of the weakly bound unstable radioactive isotopes. In order to observe the break-up effect, reaction cross-sections are extracted and compared with the previously reported ones.

Employing Coulomb and proximity potentials, cluster-decay half-lives ($T_{1/2}^{c,\mathrm{\text{th}}}(s)$) of even–even nuclei had been calculated and, the obtained results are compared with the experimental ones. To investigate cluster radioactivity in superheavy nuclei (SHN), we determine the required disintegration energies ($Q_c$-values) utilizing periodic-orbit theory within microscopic-macroscopic formalism and hence, predict the logarithmic values of $T_{1/2}^{c,\mathrm{\text{th}}}(s)$ for even–even SHN with $Z=122$, 124 and 126. Among various isotopes of daughter nuclei, products produced with minimum value of Gibbs free energy are chosen for our investigation. Moreover, study of the branching ratios would make us to find the dominant mode of decay among $\alpha$-decay, spontaneous fission (SF) and cluster-decay in these SHN. Mostly, the emissions of Kr-, Sr-, Zr- and Mo-clusters from these superheavy nuclei are found to be the dominant modes of decay which can be attributed to strong shell effects in the neighborhood of $Z=82$ region. Our results are in agreement with those obtained using UDL method except for few cases. We believe that this work can play a significant role in the study of decay properties of superheavy nuclei.

Spin correlation coefficients in elastic scattering of leptons on the deuteron are studied in the one-photon-exchange Born approximation within the limit of zero lepton mass. Numerical estimations for the spin correlation coefficients caused by a polarized beam and a vector polarized target are presented and analyzed at various beam energies and scattering angles in two coordinate systems which are relevant for experiment. The influence of the obtained results on the nucleon structure is investigated, and a considerable dependence at incident beam energies greater than 1fm${}^{-1}$ and backward scattering angles is found. The estimated results are of particular interest for encouragement of experimental measurements of lepton-deuteron scattering which aim for accurate calculation of the charge radius of the proton to a high degree of precision. These results may also stimulate new generation of measurements of different physical observables very sensitive to the spin structure of the nucleon and light nuclei.

Neutrinos play an important role in core-collapse supernova events since they are a key piece to understanding the explosion mechanisms. The analysis of the neutrino fluxes can bring answers to neutrino’s related problems e.g., mass hierarchy, spectral splitting, sterile neutrinos, etc. In this work, we study the impact of neutrino oscillations and the possible existence of eV sterile neutrinos upon the supernova neutrino flux ($F_{\nu }(E)$). We have calculated the energy distribution of the neutrino flux from a supernova and the total number of events that would be detected in a liquid scintillator. We also present an analysis for the conversion probabilities as a function of the active-sterile neutrino mixing parameters. Finally, we have carried out a statistical analysis to extract values for the mixing parameters of the model.

Experimental results on the search and investigation of the possible pp$\pi$ resonance states in inelastic ${}^{12}$C${}^{12}$C collisions at 3.37 $A$ GeV are presented. The statistically significant peak structure with mass $M(pp{\pi }^{+})=2117.8\pm 1.2$MeV and Breit–Wigner width $\mathrm{\Gamma }=4.1\pm 1.1$MeV has been observed for the first time in the spectrum of invariant masses of pp${\pi }^{+}$ system in ${}^{12}$C${}^{12}$C collisions at 3.37 $A$ GeV. The inclusive cross-section of the formation of this possible eight quark pp${\pi }^{+}$ resonance state has been estimated to be ${\sigma }_{\mathrm{\text{incl}}}=4.93\pm 0.86$mb. The significant maximum structure with the center estimated at $M(pp)\approx 1930\pm 5$MeV, and having a narrow width ($<10$MeV), has been observed in the spectrum of the invariant masses of two protons in ${}^{12}$C${}^{12}$C collisions at 3.37 $A$ GeV when the value of the invariant mass $M(pp{\pi }^{+})$ of the pp${\pi }^{+}$ system falls inside the region of the observed pp${\pi }^{+}$ resonance structure: $2110\le M(pp{\pi }^{+})\le 2126$MeV.

Breakup reactions involving heavy targets are known to be dominated by the Coulomb breakup, and this is understood as due to the long-range nature of Coulomb forces and a large charge of the target nucleus. In this paper, we intended to find out whether these two factors alone can justify the large importance of the Coulomb breakup over its nuclear counterpart. To this end, we considered the ${}^{15}\mathrm{\text{C}}+{}^{208}\mathrm{\text{Pb}}$ breakup reaction at an incident energy of $E_{\mathrm{\text{lab}}}=68\mathrm{\text{MeV/nucleon}}$. By analyzing this reaction, it is found that the continuum–continuum couplings and higher-order multipole transitions, which are characteristic of nuclear reactions induced by loosely bound projectiles, strongly suppress the nuclear breakup cross-section and have a negligible effect on the Coulomb breakup cross-section. When these reaction dynamics are removed, the nuclear breakup cross-section becomes more important than the Coulomb breakup cross-section at large incident angles.

In conclusion, these results infer that the predominance of the Coulomb breakup over the nuclear breakup in reactions involving heavy targets can be explained by three main factors: the large target charge and the long-range nature of Coulomb, as well as the prevailing reaction dynamics such as continuum–continuum couplings and higher-order multipole transitions. These results could motivate further improvements on the theoretical approaches used in pure Coulomb breakup calculations.

The available experimental data for the elastic scattering of isobar nuclei ⁶Li and ⁶He on ${}^{12}$C nuclei have been reanalyzed in a wide energy range of energy from 5.8MeV to 600MeV using the optical model with Distorted Wave Born Approximation (DWBA), and coupled reaction channel method (CRC) where inelastic scattering and transfer have been involved during calculations. A semi-microscopic potential, namely double-folding cluster model (DFC) has been used to investigate the cluster structure for both projectiles and target which was folded with Distorted Wave Born Approximation (DWBA) as a real part of potential where the imaginary part was taken in Woods–Saxon (WS) shape. The crystal model method has been applied to ⁶Li, ⁶He elastically scattered by ${}^{12}$C, and reliable analysis of the considered experimental data has been obtained.

The study of neutron-deficient Kr isotopes in mass range $A=70$–80, which is in the transitional region, is quite interesting. These isotopes show different structures, particularly in ${}^{76}\mathrm{\text{Kr}}$ shape coexistence near ground state has been observed. In this work, the multi-quasiparticle triaxial projected shell model (TPSM) is employed to study the high spin band structures and to depict $\gamma$ deformation in ${}^{76}\mathrm{\text{Kr}}$ nucleus. A triaxial configuration is a superposition of several K-states and the projected states result in various bands originating from the same intrinsic configuration. The yrast-, $\gamma$- and 2$\gamma$ bands are studied and explained in the framework of TPSM approach.

This paper investigates the predictive power of the macroscopic and microscopic models in alpha-decay of actinide nuclei. Macroscopic theoretical models such as Coulomb and Proximity potential model (CPPM), Modified generalized liquid drop model (MGLDM) and Effective liquid drop model (ELDM) are applied in predicting the alpha-decay half-lives of actinide nuclei. The half-lives produced by these macroscopic models are compared with that of microscopic models such as Cluster model with two-potential approach (CM), Microscopic cluster model (MCM), Multichannel cluster model (MCCM) and that of experiments. The deviation of these models with the experiments is quantified using statistical treatment such as root mean square deviation $\sigma$ (RMSD), mean deviation ($\bar{\delta }$), index $\bar{f}$ and root mean square error (RMSE). It is found that among the microscopic and macroscopic models, ELDM and MCCM are, respectively, found to be accurate than that of other models. The microscopic model MCCM produces alpha-decay half-lives close to the experiments in the actinide region. The appropriate mass excess values have been identified to predict the exact alpha-decay half-lives in the actinide region.

For the activation of the target nucleus, bremsstrahlung photons generated in a medical linear accelerator can be used. Due to particle separation energy limitations for low photon energies in the giant resonance region ($\sim$18MeV), the reaction exit channels are restricted to the ejection of one or two particles only. Thus, the gamma spectrum is relatively clear, and the use of ancillary detectors coupled to HPGe is not highly needed. In this study, the bremsstrahlung photons have been used for the activation of the titanium target. ${}^{46-48}$Sc isotopes are observed from the natural titanium target via photo-proton reactions. Decay radiations from the isotopes and half-life of ${}^{47}$Sc which is from the most abundant natural titanium have been determined consistent with the literature values.

L. Y. Jia recently proposed an algorithm that applies the variational method directly to coherent-pair condensates (VDPC) [L. Jia, Phys. Rev. C (2019).] Now I’ll make changes to the VDPC algorithm that applies it to the Constraint Hatree–Fock theory. I derived expressions of the mean energy extremum with linear constraints and the analytic form of the Lagrangian multiplier. In addition, I acquire an angle through the inverse tangent of the energy minimum to the electric quadrupole moment in Fig. 3, which describes the unconstrained energy under an equivalent rotating system. I demonstrate the new algorithm in a semirealistic example using the realistic $V_{\mathrm{\text{low}}-k}$ interaction in the large model spaces (up to 15 harmonic-oscillator major shells). In this work, I am interested in a wave function $|\psi (Q)〉$, which minimizes the total energy under the constraint that has a fixed expectation $Q=〈\psi \left|\widehat{Q}\right|\psi 〉$. I graphed the results as just an energy extreme versus electric quadrupole moment graph. The result shows that Fig. 3 is similar to Fig. 7.2 in [P. Ring and P. Schuck, The Nuclear Many-body Problem (Springer Science & Business Media, 2004)].

The $\nu 1h_{11/2}$ band in ¹⁰⁰Pd is investigated by the cranking covariant density functional theory (CDFT) with the particle-number-conservation shell-model-like approach (SLAP) to treat the pairing correlations. The experimental $B(E2)$, moments of inertia, and the total angular momentum are well reproduced by our calculation. The deformations for neutrons, protons, and the whole nucleus behave in a similar way with the decreasing of $\beta$ and the tiny change of $\gamma$ with increasing rotational frequency $\hslash \omega$ from 0.2 to 0.6MeV. The features of the antimagnetic rotation (AMR) are identified by above calculation results. To conclude, the configuration of AMR for ${}^{100}$Pd given by the cranking CDFT-SLAP is $\pi$($1g_{9/2}$)${}^{-4}\otimes \nu [1h_{11/2}{(1g_{7/2})}^3]$. Furthermore, the configuration of $\pi$($1g_{9/2}$)${}^{-4}\otimes \nu [1h_{11/2}{(1g_{7/2})}^{2}2d_{5/2}]$, which presents the experimental result of low spins, is also presented.