The recently observed weakly-bound 39Na provides a stringent theoretical constraint on the neutron drip-line. We studied the properties of drip-line nuclei around 39Na with the Hartree-Fock-Bogoliubov method and various Skyrme interactions. We adopted the extended SkM*-ext1 parameterization which can properly describe two-neutron separation energies of oxygen and fluorine isotopes and deformations at the center of the "island of inversion". Systematic calculations of drip lines of O, F, Ne, Na, Mg, and Al isotopes have been performed. We infer that 42Mg is weakly bound and 45Al is less weakly bound. 44Mg and 47Al could be barely existed. We also demonstrated the deformed halo properties of 39Na. Our studies could be valuable for experimental explorations of drip-line nuclei in the forthcoming FRIB and other rare-isotope beam facilities .
Two new mechanisms active in rotating nuclei located in the vicinity of neutron drip line have been discovered. Strong Coriolis interaction acting on high-$j$ orbitals transforms particle-unbound (resonance) nucleonic configurations into particle-bound ones with increasing angular momentum. The point of the transition manifests the birth of particle-bound rotational bands. Alternative possibility of the transition from particle-bound to resonance rotational band (the death of particle-bound rotational bands) with increasing spin also exists but it is less frequent in the calculations. The birt…
In the present paper we explore the neutron-drip region of cold non-rotating isolated neutron stars. We have performed extended nuclear-structure calculations for nuclei embedded in the electron gas. For modeling the outer crust we use a set of Wigner-Seitz cells, where every cell contains one nucleus surrounded by a cloud of relativistic electrons. Above the drip point a non-relativistic neutron gas occurs in the cell. These calculations are carried out within the Hartree-Fock approach in combination with Skyrme effective interactions. For every baryon density we have determined the configura…
Proton and neutron separation energies have been calculated using the extended Bethe-Weizsacker mass formula. This modified Bethe-Weizsacker mass formula describes minutely the positions of all the old and the new magic numbers. It accounts for the disappearance of some traditional magic numbers for neutrons and provides extra stability for some new neutron numbers. The neutron and proton drip lines have been predicted using this extended Bethe-Weizsacker mass formula. The implications of the proton drip line on the astrophysical rp-process and of the neutron drip line on the astrophysical r-p…
The structure of Ne, Na, Mg, Al, Si and S nuclei near the neutron drip-line region is investigated in the frame-work of relativistic meannfield (RMF) and non-relativistic Skyrme Hartree-Fock formalisms. The drip-line of these nuclei are pointed out. We analysed the large deformation structures and many of these neutron rich nuclei are quite deformed. New magic number are seen for these deformed nuclei.
Exotic and drip-line nuclei as well as nuclei immersed in a low density gas of neutrons in the outer crust of neutron stars are systematically investigated with respect to their neutron pairing properties. This is done using Skyrme density-functional and different pairing forces such as a density-dependent contact interaction and a separable form of a finite-range Gogny interaction. Hartree-Fock-Bogoliubov and BCS theories are compared. It is found that neutron pairing is reduced towards the drip line while overcast by strong shell effects. Furthermore resonances in the continuum can have an i…
We investigate how the neutron drip line is related to the density dependence of the symmetry energy, by using a macroscopic nuclear model that allows us to calculate nuclear masses in a way dependent on the equation of state of asymmetric nuclear matter. The neutron drip line obtained from these masses is shown to appreciably shift to a neutron-rich side in a nuclear chart as the density derivative of the symmetry energy increases. Such shift is clearly seen for light nuclei, a feature coming mainly from the surface property of neutron-rich nuclei.
A semi-microscopic self-consistent quantum approach developed recently to describe the inner crust structure of neutron stars within the Wigner-Seitz method with the explicit inclusion of neutron and proton pairing correlations is used for finding the neutron drip point which separates the outer and inner crusts. The equilibrium configurations of the crust are examined in vicinity of the drip point and in the upper part of the inner crust, for the density region corresponding to average Fermi momenta $k_{\rm F}{=}0.2 ÷0.5 $fm$^{-1}$.
Using HF+BCS method with Skyrme forces we analyze the neutron drip line. It is shown that around magic and new magic numbers the drip line may form stability peninsulas. It is shown the location of these peninsulas does not depend on the choice of Skyrme forces. It is found that the size of the peninsulas is sensitive to the choice of Skyrme forces and the most extended peninsulas appear with the SkI2 set.
We studied the charge radius ($r_{c}$), neutron radius ($r_n$), and neutron skin-thickness ($Δr=r_n-r_p$) over a chain of isotopes from C to Zr with the stable region to the neutron drip line. Theoretical calculations are done with axially deformed self-consistent relativistic mean-field theory (RMF) with effective nonlinear NL3 and NL3* interactions. The theoretically estimated values are compared with available experimental data and a reasonable agreement are noted. We additionally assessed the two-neutron separation energy ($S_{2n}$) to mark the drip line nuclei of the considered isotopic s…
Relativistic Hartree-Bogoliubov (RHB) theory in coordinate space is used to describe the chain of even-even Zirconium isotopes reaching from Zr116 to the drip line nucleus Zr140. Pairing correlations are taken into account by a density dependent force of zero range. For neutron numbers larger than the magic number N=82 a giant neutron halo outside the core of Zr122 is observed. It is formed by up to six neutrons.
Shell effects in nuclei close to the neutron-drip lines have been investigated. It has been demonstrated in the relativistic mean-field theory that nuclei very far from stability manifest the shell effects strongly. This behaviour is in accord with the predictions of nuclear masses in the finite-range droplet model including shell corrections. As a consequence we find a large neutron halo in nuclei near the neutron-drip line. The shell effects predicted in the existing Skyrme mean-field theory in comparison are significantly weaker than those of the other approaches.
The sources of theoretical uncertainties in the prediction of the two-neutron drip line are analyzed in the framework of covariant density functional theory. We concentrate on single-particle and pairing properties as potential sources of these uncertainties. The major source of these uncertainties can be traced back to the differences in the underlying single-particle structure of the various covariant energy density functionals (CEDF). It is found that the uncertainties in the description of single-particle energies at the two-neutron drip line are dominated by those existing already in know…
We look for collective excitations originating from the strong surface pairing in unstable nuclei near the neutron drip-line. The soft dipole excitation is such a pairing mode as it exhibits a character of core-vs-dineutron motion. Possibility of the hydrodynamic phonon mode (the Anderson-Bogoliubov mode) is also discussed.
Neutron rich He nuclei have been investigated using relativistic mean field approach in co-ordinate space. Elastic partial scattering cross sections for proton scattering in inverse kinematics have been calculated using the theoretically obtained density for $^{6,8}$He and compared with experiment. The energies of the low-lying resonance states in the neutron unstable nuclei $^{5,7}$He have also been calculated and compared with experimental observations.
We investigate unbound single-particle states in pair-correlated drip-line nuclei by describing a low-energy elastic scattering of a neutron in the $s$-wave within the framework of the coordinate space Hartree-Fock-Bogolibov (Bogoliubov-de Genne) equation. Numerical study is performed for a neutron drip-line carbon isotope where the neutron $2s_{1/2}$ orbit is located close to zero energy. Analyzing the S-matrix poles of the elastic scattering, we discuss properties of the $s$-wave quasiparticle resonance and, in particular, behaviors characteristic to drip-line nuclei. It is found that the S-…
We introduce a local-scaling point transformation to allow for modifying the asymptotic properties of the deformed three-dimensional Cartesian harmonic oscillator wave functions. The resulting single-particle bases are very well suited for solving the Hartree-Fock-Bogoliubov equations for deformed drip-line nuclei. We then present results of self-consistent calculations performed for the Mg isotopes and for light nuclei located near the two-neutron drip line. The results suggest that for all even-even elements with $Z$=10--18 the most weakly-bound nucleus has an oblate ground-state shape.
Role of pairing correlation for emergence of low-frequency vibrational excitations in neutron drip line nuclei is discussed paying special attention to neutrons with small orbital angular momentum l. Self-consistent pairing correlation in the Hartree-Fock-Bogoliubov (HFB) theory causes the change of the spatial structure of the quasiparticle wave functions; "the pairing anti-halo effect" in the lower component and "the broadening effect" in the upper component. The resultant spatial distribution of the two-quasiparticle states among low-l neutrons, "the broad localization", brings about qualit…
The relativistic mean field theory is applied to study some exotic properties of neutron rich nuclei as recently observed, namely, extension of the drip-line for $F$ nuclei from $^{29}F$ to $^{31}F$ and the appearence of a new shell closure at neutron number N=16. We find $^{31}F$ to be bound against one-neutron dripping but unbound only marginally for two neutron separation. The calculated functional dependence of one-neutron separation energy with neutron number for different values of $T_Z = (N-Z)/2$ signals a new shell closure at N=16 for neutron rich nuclei with $T_Z\ge 3$. This is furthe…
Based on the Relativistic continuum Hartree-Bogoliubov (RCHB) theory, the pseudo-spin approximation in exotic nuclei is investigated in Zr and Sn isotopes from the proton drip line to the neutron drip line. The quality of the pseudo-spin approximation is shown to be connected with the competition between the centrifugal barrier (CB) and the pseudo-spin orbital potential (PSOP). The PSOP depends on the derivative of the difference between the scalar and vector potentials $dV/dr$. If $dV/dr = 0$, the pseudo-spin symmetry is exact. The pseudo-spin symmetry is found to be a good approximation for …
We present predictions of the binding energy per nucleon and the neutron skin thickness in highly neutron-rich isotopes of Oxygen, Magnesium, and Aluminum. The calculations are carried out at and below the neutron drip line as predicted by our model. The nuclear properties are obtained via an energy functional whose input is the equation of state of isospin-asymmetric infinite matter. The latter is based on a microscopic derivation of the energy per particle in neutron matter applying chiral few-nucleon forces together with a phenomenological model for the equation of state of symmetric nuclea…
The transition density and current provide valuable insight into the nature of nuclear vibrations. Nuclear vorticity is a quantity related to the transverse transition current. In this work, we study the evolution of the strength distribution, related to density fluctuations, and the vorticity strength distribution, as the neutron drip line is approached. Our results on the isoscalar, natural-parity multipole response of Ni isotopes, obtained by using a self-consistent Skyrme-Hartree-Fock + Continuum RPA model, indicate that, close to the drip line, the low-energy response is dominated by L>1 …
The Relativistic Hartree Bogoliubov theory is applied in the mean-field approximation to the description of properties of light nuclei with large neutron excess. Pairing correlations and the coupling to particle continuum states are described by finite range two-body forces. Using standard parameter sets for the mean-field Lagrangian and the pairing interaction of Gogny-type, self-consistent solutions in coordinate space are calculated for the ground states of a number of neutron-rich nuclei. The model predicts the location of the neutron drip-line, reduction of the spin-orbit interaction, $rm…
The location of the neutron drip line, currently known for only the lightest elements, remains a fundamental question in nuclear physics. Its description is a challenge for microscopic nuclear energy density functionals, as it must take into account in a realistic way not only the nuclear potential, but also pairing correlations, deformation effects and coupling to the continuum. The recently developed deformed relativistic Hartree-Bogoliubov theory in continuum (DRHBc) aims to provide a unified description of even-even nuclei throughout the nuclear chart. Here, the DRHBc with the successful d…
Applications of configuration mixing methods for nuclei near the proton and neutron drip lines are discussed. A short review of magic numbers is presented. Prospects for advances in the regions of four new "outposts" are highlighted: $^{28}$O, $^{42}$Si, $^{60}$Ca and $^{78}$Ni. Topics include: shell gaps, single-particle properties, islands-of-inversion, collectivity, neutron decay, neutron halos, two-proton decay, effective charge, and quenching in knockout reactions.
The structure of Ne, Na, Mg, Al, Si, P and S nuclei near the neutron drip-line region is investigated in the frame-work of relativistic mean field theory and non-relativistic Skyrme Hartree-Fock formalism. The recently discovered nuclei $^{40}$Mg and $^{42}$Al, which are beyond the drip-line predicted by various mass formulae are located within these models. We find many largely deformed neutron-rich nuclei, whose structures are analyzed. From the structure anatomy, we find that at large deformation, low $Ω$ orbits of opposite parities (e.g. $\frac{1}{2}^+$ and $\frac{1}{2}^-$) occur close to …
The evolution of the N=28 neutron shell closure is studied in the N=28 isotones from neutron drip line's $^{40}$Mg to N=Z doubly magic $^{56}$Ni. It is found that the N=28 closure vanishes at Z=12 in favor of a deformed ground state. For Z=14 and Z=16 closed shell and intruder configurations are almost degenerate, leading to highly mixed ground states and to very low lying excited 0$^+$ states. For Z$>$20 the intruder states are always above the closed shell ground states. We examine their structure and their possible existence as collective yrare bands of well defined particle-hole character.
The neutron and proton drip lines represent the limits of the nuclear landscape. While the proton drip line is measured experimentally up to rather high $Z$-values, the location of the neutron drip line for absolute majority of elements is based on theoretical predictions which involve extreme extrapolations. The first ever systematic investigation of the location of the proton and neutron drip lines in the covariant density functional theory has been performed by employing a set of the state-of-the-art parametrizations. Calculated theoretical uncertainties in the position of two-neutron drip …
The canonical-basis HFB method provides an efficient way to describe pairing correlations involving the continuum part of the single-particle spectrum in coordinate-space representations. It can be applied to super-conducting deformed drip-line nuclei as easily as to stable or spherical nuclei. This method is applied to a simulation of the approach to the neutron drip line. It turns out that the HFB solution has a stronger pairing and a smaller deformation as the Fermi level is raised. However, such changes are smooth and finite. No divergences or discontinuities of the radius or other quantit…
For axially symmetric even-even nuclei, we solve the Hartree-Fock-Bogoliubov (HFB) equations on a 2-D grid in cylindrical coordinates. The Skyrme SLy4 interaction is used for the mean field and a zero-range interaction for the pairing field. After decoupling the HFB lattice equations, we obtain quasiparticle states with equivalent single-particle energies up to 100 MeV or more. We present results for the Krypton isotope chain up to the two-neutron dripline, including two-neutron separation energies, pairing gaps, and quadrupole deformations for the ground states and isomeric minima.
We discuss effects of pairing correlation on quasi-particle resonance. We analyze in detail how the width of low-lying quasi-particle resonance is governed by the pairing correlation in the neutron drip-line nuclei. We consider the 46Si + n system to discuss low-lying p wave quasi-particle resonance. Solving the Hartree-Fock-Bogoliubov equation in the coordinate space with scattering boundary condition, we calculate the phase shift, the elastic cross section, the resonance width and the resonance energy. We found that the pairing correlation has an effect to reduce the width of quasi-particle …
We solve the Hartree-Fock-Bogoliubov (HFB) equations for deformed, axially symmetric even-even nuclei in coordinate space on a 2-D lattice utilizing the Basis-Spline expansion method. Results are presented for the neutron-rich zirconium isotopes up to the two-neutron dripline. In particular, we calculate binding energies, two-neutron separation energies, normal densities and pairing densities, mean square radii, quadrupole moments, and pairing gaps. Very large prolate quadrupole deformations (beta2=0.42,0.43,0.47) are found for the (102,104,112)Zr isotopes, in agreement with recent experimenta…
Examples of the change of neutron shell-structure in both weakly-bound and resonant neutron one-particle levels in nuclei towards the neutron drip line are exhibited. It is shown that the shell-structure change due to the weak binding may lead to the deformation of those nuclei with the neutron numbers $N \approx$ 8, 20, 28 and 40, which are known to be magic numbers in stable nuclei. Nuclei in the "island of inversion" are most easily and in a simple manner understood in terms of deformation. As an example of spectroscopic properties other than single-particle energies, magnetic moments of so…
We investigate the microscopic structure of the low-lying isovector-dipole excitation mode in neutron-rich $^{36,38,40}$Mg close to the drip line by means of the deformed quasiparticle-random-phase-approximation employing the Skyrme and the local pairing energy-density functionals. It is found that the low-lying bump structure above the neutron emission-threshold energy develops when the drip line is approached, and that the isovector dipole strength at $E_{x} < 10$ MeV exhausts about $6.0 %$ of the classical Thomas-Reiche-Kuhn dipole sum rule in $^{40}$Mg. We obtained the collective dipole mo…
Low-frequency quadrupole vibrations in deformed ${}^{36,38,40}$Mg are studied by means of the deformed Quasiparticle-RPA based on the coordinate-space Hartree-Fock-Bogoliubov formalism. Strongly collective $K^π=0^{+}$ and $2^{+}$ excitation modes (carrying 10-20 W.u.) are obtained at about 3 MeV. It is found that dynamical pairing effects play an essential role in generating these modes. It implies that the lowest $K^π=0^{+}$ excitation modes are particularly sensitive indicators of dynamical pairing correlations in deformed nuclei near the neutron drip line.
The neutron-drip transition in the dense matter constituting the interior of neutron stars generally refers to the appearance of unbound neutrons as the matter density reaches some threshold density $ρ_\textrm{drip}$. This transition has been mainly studied under the cold catalyzed matter hypothesis. However, this assumption is unrealistic for accreting neutron stars. After examining the physical processes that are thought to be allowed in both accreting and nonaccreting neutron stars, suitable conditions for the onset of neutron drip are derived and general analytical expressions for the neut…
The neutron pairing correlation and the soft dipole excitation in medium-mass nuclei near drip-line are investigated from a viewpoint of the di-neutron correlation. Numerical analyses by means of the coordinate-space HFB and the continuum QRPA methods are performed for even-even $^{18-24}$O, $^{50-58}$Ca and $^{80-86}$Ni. A clear signature of the di-neutron correlation is found in the HFB ground state; two neutrons are correlated at short relative distances $\lesim 2$ fm with large probability $\sim 50%$. The soft dipole excitation is influenced strongly by the neutron pairing correlation, and…
Possible bound nuclei beyond the two-neutron drip line in the $50\leqslant Z \leqslant 70$ region are investigated by using the deformed relativistic Hartree-Bogoliubov theory in continuum with density functional PC-PK1. Bound nuclei beyond the drip lines of $_{56}$Ba, $_{58}$Ce, $_{62}$Sm, $_{64}$Gd and $_{66}$Dy are predicted, forming peninsulas of stability in nuclear landscape. Near these peninsulas, several multi-neutron emitters are predicted. The underlying mechanism of the peninsulas of stability is investigated by studying the total energy, Fermi surface, quadrupole deformation and th…
We perform the Hartree-Fock-Bogoliubov (HFB) calculations for ground states of even Mg isotopes using the Skyrme force and a density-dependent zero-range pairing force. The HFB equation is solved in a three-dimensional cartesian mesh, and a convergence of deformation is carefully examined with respect to a cut-off radius for a check of the calculations. We discuss systematics of the two-neutron separation energy, deformation and root-mean-square radius. We have found that 36,38,40Mg have appreciable static deformation, where 40Mg is a two-neutron drip-line nucleus in our calculation, and the d…
We investigate the two-neutron transfer modes induced by (t,p) reactions in neutron-rich oxygen isotopes. The nuclear response to the pair transfer is calculated in the framework of continuum-Quasiparticle Random Phase Approximation (cQRPA). The cQRPA allows a consistent determination of the residual interaction and an exact treatment of the continuum coupling. The (t,p) cross sections are calculated within the DWBA approach and the form factors are evaluated by different methods : macroscopically, following the Bayman and Kallio method, and fully microscopically. The largest cross section cor…
Low-frequency quadrupole vibrational modes in deformed $^{36,38,40}$Mg close to the neutron drip line are studied by means of the quasiparticle-random-phase approximation based on the coordinate-space Hartree-Fock-Bogoliubov formalism. Strongly collective $K^π=0^{+}$ and $2^{+}$ excitation modes carrying 10-20 Weisskopf units in the intrinsic isoscalar quadrupole transition strengths are obtained at about 3 MeV. There are two reasons for the enhancement of the transition strengths. First, the quasiparticle wave functions generating these modes possess spatially very extended structure. The asy…
Encouraged by the success of RMF+BCS approach for the description of the ground state properties of the chains of isotopes of proton magic nuclei with proton number Z=8, 20, 28, 50 and 82 as well as those of proton sub-magic nuclei with Z=40, we have further employed it, in an analogous manner, for a detailed calculations of the ground state properties of the neutron magic isotones with neutron number N = 8, 20, 28, 50, 82 and 126 as well as those of neutron sub-magic isotones with N = 40 using the TMA force parameterizations in order to explore low lying resonance and other exotic phenomenon …
We calculate positions of one- and two-particle, proton and neutron drip lines within the Hartree-Fock-Bogoliubov theory using Skyrme interaction. We also determine an approximate $r$-process path defined as a line where the neutron binding energy is equal to 2~MeV. A weakening of the nuclear shell structure at drip lines is found and interpreted as resulting from a coupling with continuum states.
Neutron drip line in calcium isotopes from a chiral interaction
Peking University（北京大学）；Texas A&M University（德克萨斯农工大学）；Oak Ridge National Laboratory（橡树岭国家实验室）；Chalmers University of Technology（查尔姆斯理工大学）；University of Tennessee, Knoxville（田纳西大学诺克斯维尔分校）；Johannes Gutenberg-Universität（约翰内斯·古腾堡大学）；University of Tsukuba（筑波大学）
We study the effects of the symmetry energy on the neutron drip density and properties of nuclei in neutron star crusts. The nonuniform matter around the neutron drip point is calculated by using the Thomas--Fermi approximation with the relativistic mean-field model. The neutron drip density and the composition of the crust are found to be correlated with the symmetry energy and its slope. We compare the self-consistent Thomas--Fermi approximation with other treatments of surface and Coulomb energies and find that these finite-size effects play an essential role in determining the equilibrium …
We have made a detailed study of the ground-state properties of nuclei in the light mass region with atomic numbers Z=10-22 in the framework of the relativistic mean-field (RMF) theory. The nonlinear $σω$ model with scalar self-interaction has been employed. The RMF calculations have been performed in an axially deformed configuration using the force NL-SH. We have considered nuclei about the stability line as well as those close to proton and neutron drip lines. It is shown that the RMF results provide a good agreement with the available empirical data. The RMF predictions also show a reasona…
We discuss the two-neutron emission decay of $^{26}$O nucleus from a viewpoint of dineutron correlations between the valence neutrons. We first discuss how the dineutron correlation is realized both in the coordinate space and in the momentum space by employing a three-body model. We then discuss the decay energy spectrum as well as the angular distribution of emitted neutrons. We show that an emission of two neutrons in back-to-back directions is enhanced, which we interpret as a clear manifestation of the dineutron correlation between the valence neutrons.
Neutron shell-structure and the resulting possible deformation in the neighborhood of neutron-drip-line nuclei are systematically discussed, based on both bound and resonant neutron one-particle energies obtained from spherical and deformed Woods-Saxon potentials. Due to the unique behavior of weakly-bound and resonant neutron one-particle levels with smaller orbital angular-momenta $\ell$, a systematic change of the shell structure and thereby the change of neutron magic-numbers are pointed out, compared with those of stable nuclei expected from the conventional j-j shell-model. For spherical…
We have done systematic Hartree-Fock-Bogoliubov calculations in coordinate space on the one-quasi-particle energies and binding energy odd-even staggering (OES) in semi-magic nuclei with the zero-range volume, mixed and surface pairing forces in order to explore the influence of their density dependence. The odd-$N$ isotopes are calculated within the blocking scheme. The strengths for the pairing forces are determined in two schemes by fitting locally to reproduce pairing gap in $^{120}$Sn and globally to all available data on the OES of semi-magic nuclei with $Z\geq8$. In the former calculati…
The predictive power of the deformed relativistic Hartree-Bogoliubov theory in continuum (DRHBc) for nuclear mass is examined in the superheavy region, $102 \le Z \le 120$. The accuracy of predicting the 10 (56) measured (measured and empirical) masses is $0.635$ ($0.642$) MeV, in comparison with $0.515$ ($1.360$) MeV by WS4 and $0.910$ ($2.831$) MeV by FRDM. Possible stability against multineutron emission beyond the two-neutron drip line is explored by the DRHBc theory, which takes into account simultaneously the deformation effects, the pairing correlations, and the continuum effects. Nucle…
We present a review of recent applications of the relativistic mean-field theory to the structure of nuclei close to the drip-lines. For systems with extreme isospin values, the relativistic Hartree-Bogoliubov model provides a unified and self-consistent description of mean-field and pairing correlations. The model has been applied in studies of structure phenomena that include: formation of neutron skin and of neutron halos in light nuclei in the mass region above the s-d neutron shell, the strong isospin dependence of the effective spin-orbit interaction and the resulting modification of sur…
It can be found that with the adequate measure, the beta stability line is equidistant from neutron and proton drip lines. We explore this fact and its predictive potentiality in the simplest case, the classic liquid drop formula.
The outer layers of a neutron star are supposed to be formed of a solid Coulomb lattice of neutron rich nuclei. At densities above neutron drip density (about one thousandth of nuclear saturation density), this lattice is immersed in a neutron fluid. Bragg scattering of those dripped neutrons by the nuclei which has been usually neglected is investigated, within a simple mean field model with Bloch type boundary conditions. The main purpose of this work is to provide some estimates for the entrainment coefficients, as required for hydrodynamical two fluid simulations of neutron star crust, whi…
An improved prescription for choosing a transformed harmonic oscillator (THO) basis for use in configuration-space Hartree-Fock-Bogoliubov (HFB) calculations is presented. The new HFB+THO framework that follows accurately reproduces the results of coordinate-space HFB calculations for spherical nuclei, including those that are weakly bound. Furthermore, it is fully automated, facilitating its use in systematic investigations of large sets of nuclei throughout the periodic table. As a first application, we have carried out calculations using the Skyrme Force SLy4 and volume pairing, with exact …
The systematics of the local energies and the two-neutron separation energies obtained in the mass predictions of infinite nuclear matter model of atomic nuclei show strong evidence of new neutron magic numbers 100,152,164, new proton magic number 78 and new islands of stability around N=100, Z $\simeq$ 62; N=152,Z=78; and N=164,Z$\simeq$90 in the drip line regions of nuclear chart,where the usual magic numbers are found to be no more valid.
We discuss a decay of unbound nuclei beyond the neutron drip-line using a three-body model with a core nucleus and two valence neutrons. We particularly discuss the role of dineutron correlation between the valence neutrons in the two-neutron emission from the ground state of $^{26}$O and $^{10}$He nuclei. Our calculations clearly indicate that the emission of the two neutrons in the back-to-back direction is enhanced due to the dineutron correlation.
Based on the relativistic calculations of the nuclear masses in the transfermium region from No $(Z=102)$ to Ds $(Z=110)$ by the deformed relativistic Hartree-Bogoliubov theory in continuum, the possible existence of the bound nuclei beyond the neutron drip lines is studied. The two-neutron and multi-neutron emission bound nuclei beyond the primary neutron drip line of $N=258$ are predicted in $Z=106,108$ and $110$ isotopes. Detailed microscopic mechanism investigation reveals that nuclear deformation plays a vital role in the existence of the bound nuclei beyond the drip line. Furthermore, no…
We have developed a new Hartree-Fock-Bogoliubov (HFB) code which has been specifically designed to study ground state properties of nuclei near the neutron and proton drip lines. The unique feature of our code is that it takes into account the strong coupling to high-energy continuum states, up to an equivalent single-particle energy of 60 MeV. We solve the HFB equations for deformed, axially symmetric even-even nuclei in coordinate space on a 2-D lattice with Basis-Spline methods. For the p-h channel, the Skyrme (SLy4) effective N-N interaction is utilized, and for the p-p and h-h channel we …
The effects of an additional $K^-$ meson on the neutron and proton drip lines are investigated within Skyrme-Hartree-Fock approach combined with a Skyrme-type kaon-nucleon interaction. While an extension of the proton drip line is observed due to the strongly attractive $K^-p$ interaction, contrasting effects (extension and reduction) on the neutron drip line of Be, O, and Ne isotopes are found. The origin of these differences is attributed to the behavior of the highest-occupied neutron single-particle levels near the neutron drip line.
