Narrow Results

Energies and widths for single-particle resonant states in the continuum in ¹²⁰Sn, as the necessary input quantities of relativistic random phase approximation for the investigation of isoscalar giant octupole resonance, are determined by analytic continuation in the coupling constant (ACCC) method within the framework of self-consistent relativistic mean field (RMF) theory for the first time. For the effective interaction NL3, the results in this scheme agree well with those of scattering phase shift method on the basis of RMF. Similar calculations are carried out in neutron-rich nucleus ⁸⁴Ni.

The effects of the presence of weakly interacting light boson (WILB) in neutron star matter have been revisited. Direct checking based on the experimental range of symmetric nuclear matter binding energy¹ and the fact that the presence of this boson should give no observed effect on the crust properties of neutron star matter, shows that the characteristic scale of WILB should be ≤2 GeV^-2. The recent observational data with significant low neutron stars radii² and the recent largest pulsar which has been precisely measured, i.e. J1903+0327 (Ref. 3) indicate that in-medium modification of WILB mass in neutron stars cannot be neglected.

The Q-values and half-lives of several heavy α decaying systems are calculated using the relativistic mean field (RMF) theory-based microscopic α-daughter nucleus potential. A unified procedure is adopted, using analytic S-matrix method and treating α-decay as the decay of the resonance state of the α-daughter nucleus system. The resonance parameters are obtained from the pole positions of the S-matrix in the complex k-plane and using these Q-values and half widths are evaluated. The calculation reproduces the experimental results well. We find that the present unified approach gives a good description of the data and compare well with those obtained by empirical formulae.

The structure of ^16-26O is investigated within the relativistic mean field (RMF) as well as high-energy nuclear collisions. The reaction cross-sections of ^16-24O+¹²C around 1 GeV are calculated within the multiple scattering theory, where the multiple integrals are evaluated by Monte Carlo method as well as by the optical limit approximation of the Glauber model. In-medium effects are investigated within the optical limit, where it is found to be important in order to get reliable information about nuclear radii and density distributions. The reaction cross-sections indicate to a halo structure for ²³O. This neutron halo is also found in the rms matter radii and nuclear densities especially when Fermi shape is used in the optical limit, including in-medium effects, in extracting the parameters of the density distributions from the experimental reaction cross-sections.

We calculate the ground state properties of recently synthesized superheavy elements (SHEs) from Z = 105–118 along with the predicted proton magic Z = 120. The relativistic and nonrelativistic mean field formalisms are used to evaluate the binding energy (BE), charge radius, quadrupole deformation parameter and the density distribution of nucleons. We analyzed the stability of the nuclei based on BE and neutron to proton ratio. We also studied the bubble structure which reveals the special features of the superheavy nuclei.

Neutron and proton driplines of single-Λ and double-Λ hypernuclei, Ξ^- hypernuclei as well as normal nuclei are studied within a relativistic mean field approach using an extended form of the FSU Gold Lagrangian density. Hyperons are found to produce bound nuclei beyond the normal nuclear driplines. Radii are found to decrease in hypernuclei near the driplines, in line with observations in light Λ hypernuclei near the stability valley. The inclusion of a Ξ^- introduces a much larger change in radii than one or more Λ's.

We calculate the ground, first intrinsic excited states and density distribution for neutron-rich thorium and uranium isotopes, within the framework of relativistic mean field (RMF) approach using axially deformed basis. The total nucleon densities are calculated, from which the cluster-structures inside the parent nuclei are determined. The possible modes of decay, like $\alpha$-decay and $\beta$-decay are analyzed. We find the neutron-rich isotopes are stable against $\alpha$-decay, however they are very much unstable against $\beta$-decay. The life time of these nuclei predicted to be tens of second against $\beta$-decay.

$Q$-value and half-life of elements in alpha decay chain of ${}^{294}$117, ${}^{293}$117, ${}^{291}$116 and ${}^{290}$116 were calculated using the Nuclear potential generated by double folding procedure and using the WKB method treating the alpha decay as a tunneling problem. The nuclear potential was parameterized using Woods–Saxon potential. Using this approach, the $Q$-value and half-life of next heaviest element in the alpha decay chain of element ${}^{290}$116 is predicted. It is proposed to use this to predict the $Q$-value and half-life of other higher elements in different alpha decay chains.

We performed calculations of nuclear systems composed solely of Λ^* hyperons, aiming at exploring the possibility of existence of absolutely stable Λ^* matter. We considered Λ^* interaction strengths compatible with the Λ^*Λ^* binding energy B_Λ^*Λ^* given by the $\overline{K}$N interaction model by Yamazaki and Akaishi. We found that the binding energy per Λ^* saturates at values well below 100 MeV for mass number A ≥ 120. The Λ^* matter is thus highly unstable against strong interaction decay.