International Journal of Modern Physics E

In a terminating band, the nucleon number changes in a specific orbital not only lead to deformation changes of the band but also the type of the band termination is impressed. In this work, we consider the role of the orbitals near the Fermi surface in some of the nuclei with $A\sim 160$; such as Dy ($Z=66$), Ho ($Z=67$) and Er ($Z=68$) isotopes. Our results show that the contribution of the number of the proton holes in the core is very effective to energy cost at the end of the rotational bands and then, termination type. Change the number of the protons on high-$j$ orbitals ($h_{11/2}$) in $N=88$ isotones and also, the neutrons on high-$j$ $i_{13/2}$ and low-$j$ $f_{7/2}{h}_{9/2}$ neutron orbitals do not affect in the type of termination. They cause only to move up or down the terminating bands in energy.

In this paper, we employ the density-dependent relativistic mean-field theory to study how the triaxiality and pairing interaction affect the inner fission barriers of actinide nuclei. It was found that the triaxiality reduced the inner barriers and improved agreement with experimental values for many actinides. However, about 1–2 MeV discrepancy to the experimental values still remained for some of the considered nuclei. Such a discrepancy could be made further smaller by increasing the BCS pairing strength parameter. In this work, we demonstrated that adjusting the paring strength was effective in reproducing the experimental inner fission barriers as well as “pairing rotational energy” and binding energy in a consistent manner for nuclei where the effect of the triaxiality on the inner barriers was significant.

In this work, we study the interaction between a complex neutral scalar boson, the axion and neutrinos, as a possible channel for the generation of the neutrino mass. We calculate one-loop corrections to the neutrino propagator and determine the value of the neutrino mass induced by the interactions with axions. We have obtained a set of relationships between the axion mass, the electron–neutrino mass and the strength of the coupling using current experimental limits on the nonobservation of the neutrinoless double beta decay.

The masses of open bottom mesons ($B$($B^{+}$,$B^0$), $\bar{B}$($B^{-}$,$\overline{B^0}$), $B_s$(${B_s}^0$, $\overline{{B_s}^0}$)) and upsilon states ($\mathrm{{\rm Y}}(1S)$, $\mathrm{{\rm Y}}(2S)$, $\mathrm{{\rm Y}}(3S)$, $\mathrm{{\rm Y}}(4S)$ and $\mathrm{{\rm Y}}(1D)$) are investigated in the isospin asymmetric strange hadronic medium at finite temperature in the presence of strong magnetic fields using a chiral effective Lagrangian approach. Here the chiral SU(3) Lagrangian is generalized to include the bottom sector to incorporate the interactions of the open bottom mesons with the magnetized medium. At finite temperature, the number density and scalar density of baryons are expressed in terms of thermal distribution functions. For charged baryons, the magnetic field introduces contribution from Landau energy levels. The masses of the open bottom mesons get modified through their interactions with the baryons and the scalar mesons, which undergo modifications in a magnetized medium. The charged $B^{+}$, $B^{-}$ mesons have additional positive mass shifts due to Landau quantization in the presence of the magnetic field. The medium mass shift of the upsilon states originates from the modification of the gluon condensates simulated by the variation of dilaton field ($\chi$) and a quark mass term in the magnetized medium. The open bottom mesons and upsilon states experience a mass drop in the magnetized medium. The masses of these mesons initially increase with a rise in temperature, and beyond a high value of temperature, their masses are observed to drop. When the temperature is below 90MeV, the in-medium masses of the mesons increase with an increase in the magnetic field. However, at high temperatures (T > 90 MeV), the masses are observed to drop with an increase in the magnetic field. These in-medium modifications can have observable effects in asymmetric heavy-ion collisions experiments.

In this paper, we investigate the effect of simultaneous variation of surface diffuseness and central depression, in case of model-dependent Fermi matter density distributions, on the estimation of survival probability, Coulomb excitation cross-section and absorption effects for ${}^{80}\text{Kr}{+}^{197}$ Au system. Further, the role of model-dependent Fermi matter density distribution and model independent $\text{D}1\text{S}$ matter density distribution has also been investigated in the estimation of the above-mentioned quantities. The simultaneous variation of the parameters of the model-dependent density distribution and choice of the density distribution are found to be affecting all the above-mentioned quantities significantly and hence plays a crucial role in the analysis of the Coulomb excitation experiments also.

In this work, we study the collective Bohr Hamiltonian of triaxial nuclei within deformation-dependent mass formalism (DDM) using the new Anharmonic potential. The Schrödinger equation with Bohr Hamiltonian is separated into two parts and the $\beta$-part is solved by mean of Nikiforov–Uvarov method to obtain the energy spectra. The $\gamma$-part is defined by a ring shape potential and solved with the same method. The energies and the $B(E2)$ transition rates for nuclide ${}^{192,194,196}$Pt are calculated and compared with the experimental data and with some others models in the same formalism.

Short range effects on inelastic C2 form factors in some open fp nuclei (${}^{46-50}$Ti, ${}^{50-54}$Cr, ${}^{54-56}$Fe and ${}^{64-68}$Zn) have been researched. The charge densities in these isotopes have been also researched by the one and two particle components of cluster series using single-particle wavefunctions of the harmonic oscillator potential. The short range effects have been inserted into the two particle components of cluster series employing the Jastrow form correlation. The total form factors of isotopes under consideration arise from the model space and core-polarization participations. The one-body density matrix elements (which are needed for computing the model space transition charge density) of valence nucleons for the transition $0^{+}\to 2^{+}$ have been computed by accomplishment of shell model calculations using the OXBASH code with various interactions. The shape of Tassie model has been adopted for computing the core-polarization transition charge density. The present computations are reliant on b (oscillator parameter) and $\beta$ (correlation parameter), where these parameters have been created independently for each individual nucleus by fitting the computed elastic form factors to those of experimental ones. This study provides a proof for strong ascendancy of short range effects on the present calculations, where inclusion of short range correlations on computations seems to be required for performing a notable modification in the computed outcomes which sequentially causes to elucidate the experimental data astoundingly in the momentum transfer under consideration.

The new experimental data on breakup of oxygen-16 nucleus on four doubly charged ($Z=+2$) fragments in ${}^{16}$O$+p$ interactions at 3.25 GeV/$c$ per nucleon are presented. The number of such interaction events (with the formation of four doubly charged fragments) with simultaneous production of ${\pi }^{+}+{\pi }^{-}+p_{\mathrm{\text{fr}}}$ with no recoil proton has proved to be equal to the number of events with simultaneous production of ${\pi }^{+}+{\pi }^{-}$ as well as $p_{\mathrm{\text{fr}}}+{\pi }^{-}$ in events with a recoil proton. For the first time, the experimental cross-section of the diffractive dissociation of the oxygen-16 nucleus on four $\alpha$-particles in ${}^{16}$O$+p$ interactions at 3.25 GeV/$c$ per nucleon has been determined to be $\sigma$ (diffr.)$=1.42\pm 0.25$ mb. The temperature of the diffractive breakup of oxygen nucleus on four $\alpha$-particles has been calculated to be $7.6\pm 0.7$ MeV within the framework of the statistical model of fast fragmentation of Feshbach–Huang–Goldhaber. Using the obtained slope of the integral distribution on the square of a transverse momentum of a recoil proton in the laboratory system for the events of diffractive breakup of an oxygen nucleus on four $\alpha$-particles, we have calculated the radius of a target proton to be $0.84\pm 0.05$ fm, which agrees very well with the corresponding radius, $0.831\pm 0.007\pm 0.012$ fm, determined a few years ago in the Jefferson Lab Proton Radius (PRad) experiment.

Boltzmann–Gibbs blast-wave model was used to analyze the transverse momentum distributions of strange hadrons ($K^{+}$, $K^{-}$, $K_S^0$, $\mathrm{\Lambda }$, $\overline{\mathrm{\Lambda }}$, ${\mathrm{\Xi }}^{-}$, ${\overline{\mathrm{\Xi }}}^{+}$, $\mathrm{\varphi }$, ${\mathrm{\Omega }}^{-}$, and ${\overline{\mathrm{\Omega }}}^{+}$) produced in most central Au+Au collisions at RHIC-BES energies. The kinetic freeze-out parameters for energies $\sqrt{s_{\text{NN}}}$$=7.7,11.5,19.6,27\text{ and }39\text{ GeV}$ are presented and discussed as a function of collision energy. The $K^{+}$, $K^{-}$, $K_S^0$, $\mathrm{\Lambda }$, $\overline{\mathrm{\Lambda }}$, ${\mathrm{\Xi }}^{-}$, ${\overline{\mathrm{\Xi }}}^{+}$, $\mathrm{\varphi }$, ${\mathrm{\Omega }}^{-}$, and ${\overline{\mathrm{\Omega }}}^{+}$ BGBW fit results are similar within errors with the kinetic freeze-out parameters of bulk hadrons (${\pi }^{\pm }$, $K^{\pm }$, p and $\overline{p}$). The multi-strange kinetic freeze-out parameters indicate that these hadrons tend to decouple earlier from the system than the bulk hadrons, having a smaller average transverse flow velocity.

The well-known statistical distribution function, Weibull distribution function, has been employed to study the multiplicity distribution and multiplicity moments for the backward shower particles produced in case of total disintegrated events of ${}^{16}$O–AgBr, ${}^{22}$Ne–AgBr and ${}^{28}$Si–AgBr interactions at (4.1–4.5) AGeV/c. Multiplicity fluctuation of backward shower particles in case of total disintegrated events by the method of scaled variance and the forward–backward asymmetry parameter had also been investigated.