Study of Neutron-Rich Λ Hypernuclei

We discuss neutron-rich hypernuclei based on the first observation of \({^{10}_\Lambda{\rm Li}}\) in the KEK-E521 experiment as well as theoretical analyses. We also discuss recent experimental results on the production of an extremely neutron-rich hypernucleus, \({^{6}_\Lambda {\rm H}}\) .     

Investigation of A^＋c- and Ab-Hypernuclei in Relativistic Mean-Field Model

We investigate the properties of A^ c- and Ab-hypernuclei within the framework of the relativistic mean-field model (RMF). It is found that no A^ c bound states can exist if the A^ c potential well depth |UA^ c| in nuclear matter is less than 10 MeV. If |UA^ c|is less than 20 MeV, A^ c cannot bind to the heavier nuclei with atomic number larger than 100. We suggest it is preferable to search the A^ c-hypernuclei from medium-heavy nuclear systems in experiment. Very small spin-orbit splitting for the A^ c in hypernuclei is a/so observed, and for the Ab it is nearly zero.     

A Reliability Analysis of Calculated Results for Odd-Even and Odd-Odd Nuclei in Relativistic Mean-Field Theory

We calculate the binding energies of Ni, Cu, Xe, Cs, Pt, Au, Np, Pu isotope chains using two interaction parameter sets NL-3 and NL-Z, and compared the relative errors of the even-even nuclei with those of odd-even nuclei and odd-odd nuclei. We find that the errors of binding energy of odd-even and odd-odd nuclei are not bigger than the one of even-even nuclei. The result shows that comparing with even-even nuclei, there is no systematic error and approximation in the calculations of the binding energy of odd-even and odd-odd nuclei with relativistic mean-field theory. In addition, the result is explained theoretically.     

Hyperon Haloes in A Hypernuclei in the Relativistic Continuum Hartree—Bogoliubov Theory

We investigate the existence of a single-Α hyperon halo in 3Α^15C and a two-Α hyperon halo in 4Α^16C.Ground-state properties of hyperon carbon isotopes,such as density distributions,single particle levels in the canonical basis,the binding energy,Α separation energy and radii,are calcuated and discussed by using the relativistic continuum Hartree-Bogoliubov theory.The hyperon halo phenomenon in 3Α^15C and 4Α^16C is supported by the discussion of the weakly bound state 1p3/2,extended density distribution and small separation energy of the Α hyperon.     

The Importance of Anisotropy for Relativistic Fluids with Spherical Symmetry

It is shown that an effective anisotropic spherically symmetric fluid model with heat flow can absorb the addition to a perfect fluid of pressure anisotropy, heat flow, bulk and shear viscosity, electric field and null fluid. In most cases the induction of effective heat flow can be avoided.     

Theoretical Investigation into Production of Double-Λ Hypernuclei from Stopped Ξ − on 6Li

We have investigated theoretically a feasible nuclear reaction to produce light double-Λ hypernuclei by choosing a suitable target. In the reaction from stopped Ξ ^? on ⁶Li target light doubly-strange nuclei, ${^5_{\Lambda\Lambda}{\rm H}}$ and ${^6_{\Lambda\Lambda}{\rm He}}$ , are produced: we have calculated the formation ratio of ${^5_{\Lambda\Lambda}{\rm H}}$ to ${^6_{\Lambda\Lambda}{\rm He}}$ for Ξ ^? absorptions from 2S, 2P and 3D orbitals of Ξ ^?–⁶Li atom by assuming a d?α cluster model for ⁶Li. From this cluster model the d?α relative wave functions has a node due to Pauli exclusion among nucleons belonging to d and α clusters. Two kinds of d?α wave functions, namely 1s relative wave function with a phenomenological one-range Gaussian (ORG) potential and that of an orthogonality-condition model (OCM) are used. It is found that the probability of ${^5_{\Lambda\Lambda}{\rm H}}$ formation is larger than that of ${^6_{\Lambda\Lambda}{\rm He}}$ for all absorption orbitals: in the case of the major 3D absorption their ratio is 1.08 for ORG and 1.96 for OCM. The dominant low momentum component of the d?α relative wave function favors the ${^5_{\Lambda\Lambda}{\rm H}}$ formation with a low Q value compared to the ${^6_{\Lambda\Lambda}{\rm He}}$ formation with a high Q value. We have also calculated momentum distributions of emitted particles, d and n, displaying continuum spectra for single-Λ hypernuclei, ${^4_{\Lambda}{\rm H}}$ and ${^5_{\Lambda}{\rm He}}$ , and line spectra for the ${^5_{\Lambda\Lambda}{\rm H}}$ and ${^6_{\Lambda\Lambda}{\rm He}}$ nuclei. Thus, our present theoretical analysis would be a significant contribution to experiments in the strangeness ?2 sector of hypernuclear physics.     

Dynamical Structure of A≤4 Λ Hypernuclei

Based on variational method,we systematically studied the dynamical structures of A≤4 S shell Λ hypernuclei with the aid of the harmonic oscillator product expansions and the generalized Talmi-Moshinsiky transformation.We also made investigations on structures of the osdinary nuclei for A=2 and 3. By comparis on,we can see that the root mean distances between nucleons are shorten due to the presence Λ hyperon which compresses the core. Λ hyperon acts as the adhesive. The studies on internal structures of nuclear system show that the relative motions between particles are mainly in 0s orbits.     

A Schematic Calculation of the ββ-Decay Matrix Element Within the Green Function Approach

The time integral representation of the many-body Green function describing the two-neutrino double-beta-decay (2-decay) matrix element is used in schematic calculations within the proton-neutron Lipkin model. The two-body Hamiltonian considered includes a quadratic polynomial in bosons to describe the motion of the selected degrees of freedom. The beta-transition operators also include higher-order terms in the boson expansion. They have been shown to be of crucial importance in the determination of the 2-decay matrix element M _F. We have found that in the standard QRPA approach, which exploits the form of M _F with denominator, there is a dominant unphysical contribution to M _F arising from the non-orthogonality of the initial and final quasiparticle ground states. The physical part of M _F is negligible for small values of the particle-particle interaction strength, i.e., it exhibits a different behavior as that known from the QRPA approaches.     

Study of Neutron-Rich Hypernuclei by the (π −, K +) Reaction at J-PARC

We are planning to perform an experiment at J-PARC and produce new neutron-rich Λ hypernuclei by using the (π ^?, K ⁺) reaction (J-PARC E10). As the first step, we are planning to produce ${^6_{\Lambda}{\rm H}}$ hypernuclei with a ⁶Li target. To conduct this experiment, we are developing new detectors, those are scintillating fiber tracker, and silicon strip detector, for high rate operation to aim at increasing beam intensity up to 10⁷/spill. As a result of beam test in Jun 2012, we are going to use high-rate beam at least 10⁷/spill.     

Relativistic Multichannel Theory：Theoretical Study of C^＋ Autoionization States

Based on relativistic multichannel theory,the autoionization states of C are studied.We calculate all the autoionization states in the energy region of 193900-231700cm^-1,and the results are in good agreement with the experimental data.The energy structure we obtain will be important in the dielectronic recombination processes,which plays a key role in determining the abundance of carbon in a nebula.     

Study of Light Hypernuclei by the (e,e′K +) Reaction

We have been performing Λ hypernuclear spectroscopic experiments by the (e,e′K ⁺) reaction since 2000 at Thomas Jefferson National Accelerator Facility (JLab). The (e,e′K ⁺) experiment can achieve a few 100 keV (FWHM) energy resolution compared to a few MeV (FWHM) by the (K ^?, π ^?) and (π ⁺, K ⁺) experiments. Therefore, more precise Λ hypernuclear structures can be investigated by the (e,e′K ⁺) experiment. ${^{7}_{\Lambda}{\rm He}}$ , ${^{9}_{\Lambda}{\rm Li}}$ , ${^{10}_{\Lambda}{\rm Be}}$ , ${^{12}_{\Lambda}{\rm B}}$ , ${^{28}_{\Lambda}{\rm Al}}$ , and ${^{52}_{\Lambda}{\rm V}}$ were measured in the experiment at JLab Hall-C. In addition, ${^{9}_{\Lambda}{\rm Li}}$ , ${^{12}_{\Lambda}{\rm B}}$ , and ${^{16}_{\Lambda}{\rm N}}$ were measured in the experiment at JLab Hall-A.     

Structure of A=11 double-Λ hypernuclei studied withthree-body forces

The energy levels and ΛΛ bond energy of the double-Λ hypernucleus ¹¹Be are calculated considering two- and three-nucleon forces. The interactions between the constituent particles are contact interactions that reproduce the low-energy binding energy of the nuclei. Effective action is constructed to involve the three-body forces. In this paper, we compare the binding energy result that is obtained with the experimental and other modern nucleon-nucleon potentials. The results of all the schemes agree very well, showing the high accuracy of our present ability to calculate the many-nucleon bound state with three-body forces. The experimental value of B_{Λ Λ}(_ΛΛ¹¹Be)=20.83 MeV seems to be more compatible with our calculated value of B_ΛΛ(_ΛΛ¹¹Be)=19.31 MeV in comparison with the calculated result of 18.23 MeV by Hiyama et al.     

Theoretical Study of Relativistic Retardation Effects： the Abnormal Fine Structure of OⅡ

Using multi-configuration Dirac-Fock and relativistic configuration interaction methods with high-order corrections, we report our precise calculation results of the fine-structure energy levels of the ground-state configuration of OⅡ（1s^22s^22p^3）. Our calculated fine-structure splittings of ^2D3/2,5/2 and ^2p1/2,3/2 are abnormal We elucidate that the transverse （Breit） interaction, i.e. relativistic retardation effect, plays an important role for the abnormal fine-structure splittings. Our calculation results are in good agreement with experimental measurements.     

Refined Study of ECR Wave Propagation and Absorption in the Weakly Relativistic Plasma

The ECR wave heating is now a routine method for plasma heating and profile control in fusion devices and also in plasma applications. Theoretical study of ECR wave propagation and absorption began very early in 1950‘s. Basic theoretical work had accomplished in 1970～1980. For toroidal devices like the tokamak, the fundamental O-mode and X-mode with nearly perpendicular propagation were used very often. For pure O-mode and X-mode with kx=O,     

A New Approach to the Relativistic Schrödinger Equation with Central Potential: Ansatz Method

Applying an ansatz to the eigenfunction, we obtain the exact closed-form solutions of the relativistic Schrödinger equation with the potential V(r) = –a/r + b/r^1/2 both in three dimensions and in two dimensions. The restrictions on the parameters of the given potential and the angular momentum quantum number are also presented.     

Study of the Impact of Relativistic Double Star Systems on the Earth’s Electric Field

Russian Physics Journal - Dependences of the effective amplitudes of the Earth's electric field (EEF) components spectrally localized at double rotation frequencies of relativistic double...     

α Decay Properties of Even-Even Nuclei~(296-308)120 Within the Two-Potential Approach

In the present work,we predict the α decay half-lives of unknown even-even nuclei ~(296-308)120 within the two-potential approach,whose α decay energy Qa is calculated using WS3+mass model.To reduce the deviations between the predictions and experimental data due to nuclear shell effect,the analytic formula of α decay hindrance factor is introduced to the two-potential approach,whose parameters had been extracted from even-even nuclei in the region of 82 Z 126 and 152 N 184 in our previous work [Deng et al.,Chin.Phys.C 42(2018) 044102].In addition,for comparing,we use a type of α decay general formula Universal Decay Law(UDL) and a semi-empirical formula in the superheavy nucleus(SEMFLS) to calculate the half-lives of even-even nuclei ~(296-308)120.The results indicate that our predicted values and the calculated values of the above two empirical formulas are mutually confirmed.Meanwhile,we systematically study α decay chains of ~(296-308)120 and predict the decay modes for superheavy nuclei to help to identify new superheavy isotopes.     

A Re-interpretation of the Concept of Mass and of the Relativistic Mass-Energy Relation

For over a century the definitions of mass and derivations of its relation with energy continue to be elaborated, demonstrating that the concept of mass is still not satisfactorily understood. The aim of this study is to show that, starting from the properties of Minkowski spacetime and from the principle of least action, energy expresses the property of inertia of a body. This implies that inertial mass can only be the object of a definition—the so called mass-energy relation—aimed at measuring energy in different units, more suitable to describe the huge amount of it enclosed in what we call the “rest-energy” of a body. Likewise, the concept of gravitational mass becomes unnecessary, being replaceable by energy, thus making the weak equivalence principle intrinsically verified. In dealing with mass, a new unit of measurement is foretold for it, which relies on the de Broglie frequency of atoms, the value of which can today be measured with an accuracy of a few parts in 10⁹.     

Application of Doppler Backscattering for Alfvén Mode Study on the Globus-M Spherical Tokamak

Physics of Atomic Nuclei - The Alfvén oscillations were studied using the multifrequency Doppler backscattering (DBS) method on the Globus-M spherical tokamak during the neutral deuterium...