Effect Of Tensor Force Research Articles

Effect of tensor force on the shell structure of superheavy nuclei

We study the effect of tensor interaction on the shell structure of superheavy nuclei in the frame of the deformed Skyrme Hartree-Fock+BCS model. To this end, we adopt four different Skyrme interactions; SLy5 without tensor interaction, and SLy5+T, T24 and T44 with tensor interaction. The calculation with SLy5+T interaction reproduce the single particle spectra of protons and neutrons in 249Bk and 251Cf, better than the other calculations with SLy5, T24 or T44 interaction. The large shell gaps of superheavy nuclei (SHE) are found at Z=114 and Z=120 for protons and N=184 for neutrons with the spherical shape irrespective of the tensor correlations. It is also found that Z=114 and N=164 shell gaps are more pronounced by SLy5+T interaction with the tensor correlations.

Delineating effects of tensor force on the density dependence of nuclear symmetry energy

In this talk, we report results of our recent studies to delineate effects of the tensor force on the density dependence of nuclear symmetry energy within phenomenological models. The tensor force active in the isosinglet neutron roton interaction channel leads to appreciable depletion/population of nucleons below/above the Fermi surface in the single-nucleon momentum distribution in cold symmetric nuclear matter (SNM). We found that as a consequence of the high momentum tail in SNM the kinetic part of the symmetry energy Ekinsym(ρ) is significantly below the well-known Fermi gas model prediction of approximately 125(ρ/ρ0)2/3. With about 15% nucleons in the high momentum tail as indicated by the recent experiments at J-Lab by the CLAS Collaboration, the Ekinsym(ρ) is negligibly small. It even becomes negative when more nucleons are in the high momentum tail in SNM. These features have recently been confirmed by three independent studies based on the state-of-the-art microscopic nuclear many-body theories. In addition, we also estimate the second-order tensor force contribution to the potential part of the symmetry energy. Implications of these findings in extracting information about nuclear symmetry energy from nuclear reactions are discussed briefly.

Systematic study of tensor force effect on pseudospin orbital splittings in Sn isotopes

The tensor force effect on the proton pseudospin orbital splittings of the 1 and 1 states in Sn isotopes is systematically analyzed with 36 sets of the TIJ interactions in the framework of the Hartree–Fock–Bogoliubov approach. It is shown that not all tensor parametrizations preserve the pseudospin symmetry.

Semi-realistic nucleon-nucleon interactions with improved neutron-matter properties

New parameter-sets of the semi-realistic nucleon-nucleon interaction are developed, by modifying the M3Y interaction but maintaining the tensor channels and the longest-range central channels. The modification is made so as to reproduce microscopic results of neutron-matter energies, in addition to the measured binding energies of doubly magic nuclei including $^{100}$Sn and the even-odd mass differences of the Z=50 and N=82 nuclei in the self-consistent mean-field calculations. Separation energies of the proton- or neutron-magic nuclei are shown to be in fair agreement with the experimental data. With the new parameter-sets M3Y-P6 and P7, the isotropic spin-saturated symmetric nuclear matter remains stable in the density range as wide as $\rho\lesssim 6\rho_0$, while keeping desirable results of the previous parameter-set on finite nuclei. Isotope shifts of the Pb nuclei and tensor-force effects on shell structure are discussed.

Effects of tensor forces in nuclei

Recent studies of nuclei far from the stability line have revealed drastic changes in nuclear orbitals and reported the appearance of new magic numbers and the disappearance of magic numbers observed at the stability line. One of the important reasons for such changes is considered to be because of the effect of tensor forces on nuclear structure. Although the role of tensor forces in binding very light nuclei such as deuterons and 4He has been known, direct experimental evidence for the effect on nuclear structure is scarce. In this paper, I review known effects of tensor forces in nuclei and then discuss the recently raised question of s–p wave mixing in a halo nucleus of 11Li. Following these reviews, the development of a new experiment to see the high-momentum components due to the tensor forces is discussed and some of the new data are presented.

The effect of the tensor force on the bubble structure in Ar isotopes

The tensor force effect on the proton bubble structure of Ar isotopes is investigated in the framework of the Hartree-Fock-Bogoliubov (HFB) approach with the Skyrme interactions SLy5+T and SLy5+Tw. It is shown that the tensor force effect of the SLy5+Tw interaction favors the bubble structure of 44-56Ar due to the inversion between the proton single-particle states \( 2s_{1/2}\) and \( 1d_{3/2}\) ( \( 2s_{1/2}\) -1d3/2 inversion). However, the SLy5+T interaction cannot lead to any \( 2s_{1/2}\) -1d3/2 inversion of Ar isotopes, consequently, no bubble structure can be found in the isotopes. In addition, taking 46Ar as an example, the competition between the tensor force and pairing interaction on the bubble formation is examined in order to understand the bubble formation mechanism.

26pXB-7 M1遷移のEnergy-weighted sum-ruleに対するテンソル力の影響(26pXB 核構造・中重核・多体基礎論,理論核物理領域)

26pXB-7 M1遷移のEnergy-weighted sum-ruleに対するテンソル力の影響(26pXB 核構造・中重核・多体基礎論,理論核物理領域)

Effect of Tensor Force on the Multipole Resonances of Finite Nuclei

The effect of the tensor force on the properties of finite nuclei is discussed by analyzing the multipole giant resonances in 208 Pb. It is found that the tensor force has a larger effect on the spin-flip magnetic dipole and Gamow-Teller resonances than on the natural parity low-lying isoscalar quadrupole (2 + ) and octupole (3 � ) states. By analyzing the modifications to the Hartree-Fock mean field induced by the tensor terms, and the specific features of the residual particle-hole tensor interaction, we find that the tensor force gives an attractive contribution to the particle-hole matrix elements.

Tensor Force Effects on - Clustering of 8Be

The Brueckner theory is applied to the antisymmetrized molecular dynamics (AMD) of 8 Be with the aim of studying the clustering mechanism on the basis of the realistic nuclear force. The role of the tensor force in the clustering is investigated through the analysis of single-particle energies depending on the single-particle orbits, which change from onecenter atomic orbits to two-center molecular orbits with the development of the α-α cluster structure. The clustering is intensified by the suppression of the attractive tensor force role in the one-center atomic orbits in the shell model structure. Subject Index: 210, 211

Novel Features of Nuclear Forces and Shell Evolution in Exotic Nuclei

Novel simple properties of the monopole component of effective nucleon-nucleon interactions are presented, leading to the so-called monopole-based universal interaction. Shell structures are shown to change as functions of N and Z, consistent with experiments. Some key cases of this shell evolution are discussed, clarifying the effects of central and tensor forces. The validity of the present tensor force is examined in terms of the low-momentum interaction V(lowk) and the Q(box) formalism.

Tensor force effects on nuclei by the mean-field calculation

We studied tensor-force effects on nuclear shell structures by mean-field calculations. We have found that the tensor force affects single-particle energies of nuclei, for example, F and Sb isotopes, in interesting ways different from what the spin-orbit force produces.

Neutron-proton interaction in rare-earth nuclei: Role of tensor force

We investigate the role of the tensor force in the description of doubly odd deformed nuclei within the framework of the particle-rotor model. We study the rare-earth nuclei 174Lu, 180Ta, 182Ta, and 188Re using a finite-range interaction, with and without tensor terms. Attention is focused on the lowest K=0 and K=1 bands, where the effects of the residual neutron-proton interaction are particularly evident. Comparison of the calculated results with experimental data evidences the importance of the tensor-force effects.

Low-momentum nucleon–nucleon interaction and Fermi liquid theory

We use the induced interaction of Babu and Brown to derive two novel relations between the quasiparticle interaction in nuclear matter and the unique low-momentum nucleon–nucleon interaction V low k in vacuum. These relations provide two independent constraints on the Fermi liquid parameters of nuclear matter. We derive the full renormalization group equations in the particle–hole channels from the induced interaction. The new constraints, together with the Pauli principle sum rules, define four combinations of Fermi liquid parameters that are invariant under the renormalization group flow. Using empirical values for the spin-independent Fermi liquid parameters, we are able to compute the major spin-dependent ones by imposing the new constraints and the Pauli principle sum rules. The effects of tensor forces are discussed.

Instanton and Tensor-Force Effects in the Strong Decays of Mesons

The strong decays of mesons are studied in the framework of the 3 P 0 model with a momentum-dependent vertex. The meson wave functions are obtained from quark-antiquark potentials including a finite quark size, instanton effects, spin-orbit and tensor-force effects. Several prescriptions for treating the decays into three mesons are proposed and analyzed. Comparison to experimental data is presented in detail.

Tensor force in doubly odd deformed nuclei

We study the nucleus ${}^{176}\mathrm{Lu}$ within the framework of the particle-rotor model. The aim of this study is to obtain information on the residual neutron-proton interaction in doubly odd deformed nuclei. To this end, both zero-range and finite-range interactions are considered with particular attention focused on the role of the tensor force, which is still a controversial issue. A detailed comparison of the calculated results with experimental data provides clear evidence of the importance of the tensor-force effects.

4He binding energy calculation including full tensor-force effects.

The four-body equations of Alt, Grassberger, and Sandhas are solved in the version where the (2)+(2) subamplitudes are treated exactly by convolution, using one-term separable Yamaguchy nucleon-nucleon potentials in the $^{1}\mathrm{S}_{0}$ and $^{3}\mathrm{S}_{1}$${\mathrm{\ensuremath{-}}}^{3}$${\mathrm{D}}_{1}$ channels. The resulting ${j}^{p}$${=1/2}^{+}$ and ${(3/2}^{+}$ three-body subamplitudes are represented in a separable form using the energy-dependent pole expansion. Converged bound-state results are calculated for the first time using the full interaction, and are compared with those obtained from a simplified treatment of the tensor force. The Tjon line that correlates three-nucleon and four-nucleon binding energies is shown using different nucleon-nucleon potentials. In all calculations the Coulomb force has been neglected.

2H(d

The tensor analyzing power ${A}_{\mathrm{yy}}$(\ensuremath{\theta}), vector analyzing power ${A}_{y}$(\ensuremath{\theta}), and cross section \ensuremath{\sigma}(\ensuremath{\theta}) of the $^{2}\mathrm{H}$(d\ensuremath{\rightarrow},\ensuremath{\gamma}${)}^{4}$He reaction have been measured for the angular range of 55\ifmmode^\circ\else\textdegree\fi{}--149\ifmmode^\circ\else\textdegree\fi{} in the center of mass system at an incident deuteron energy of 95 MeV. The reaction is dominated by the ${〈}^{1}$${D}_{2}$\ensuremath{\Vert}E2${\ensuremath{\Vert}}^{1}$${S}_{0}$〉 transition involving the S-state component of $^{4}\mathrm{He}$, as indicated by the approximately ${\mathrm{sin}}^{2}$2\ensuremath{\theta} angular distribution of the cross section. The observed deviation of \ensuremath{\sigma}(\ensuremath{\theta}) from this shape is due to either M2 strength, tensor force effects, or both. The tensor analyzing power ${A}_{\mathrm{yy}}$(\ensuremath{\theta}) is nearly isotropic, with a typical value of approximately 0.3\ifmmode\pm\else\textpm\fi{}0.1. The vector analyzing power ${A}_{y}$ is zero within the statistical precision (typically \ifmmode\pm\else\textpm\fi{}0.2) of this data set, indicating a reduced contribution from E1 and M2 transitions compared to lower energies. Direct capture calculations in the plane-wave Born approximation do not reproduce even the sign of ${A}_{\mathrm{yy}}$.

Tensor-force effects in the 2H(d

Vector analyzing powers, tensor analyzing powers, and relative differential cross sections have been measured for the $^{2}(\mathrm{d}\ensuremath{\rightarrow}$,\ensuremath{\gamma}${)\mathrm{}}^{4}$He reaction at an incident energy of 10 MeV. Multipole decomposition and partial-wave analysis reveal that about 15% of the cross section involves processes in which the tensor force plays a role, either in the entrance or exit channel. Contrary to earlier claims, the reaction cannot be used to determine the D-state admixture in the $^{4}\mathrm{He}$ wave function unless the D state of the deuteron and other tensor-force effects in the entrance channel are taken into account.

The effect of tensor forces in the three-body calculations

Abstract A three-body model is used in calculating the binding energies of the nuclei 3H, 3He and 6Li. The two-body interactions contain both attraction and repulsion, as well as it include tensor forces. The effect of tensor forces is found to improve the binding energies by about 4.5% – 8.3%.

Recent Progress in Understanding Trinucleon Properties

The traditional approach of nuclear physics describes nuclei by means of a model in which nonrelativistic nucleons interact via two-body or pair-wise forces. In this brief review we concentrate entirely on the three- and four-nucleon systems, with emphasis on three-nucleon calculations using realistic forces. We focus our discussion on advances in three topics that have preoccupied researchers recently: meson-exchange currents and the trinucleon charge and magnetic densities and form factors; three-nucleon forces and their effect on observables, and the effect of the nucleon-nucleon tensor force on observables. Clearly, a comprehensive study of any of these topics is beyond our resources. Fortunately, several related themes recur and unite these disparate topics, and we concentrate on these.