D. J. Millener
Information on Lambda-7Li, Lambda-9Be, Lambda-10B, Lambda-11B, Lambda-12C, Lambda-15N, and Lambda-16O from the Ge detector array Hyperball is interpreted in terms of shell-model calculations that include both Lambda and Sigma configurations with p-shell cores. It is shown that the data puts strong constraints on the effective Lambda-N interaction.
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A large number of hypernuclei, where a considerable fraction of nucleons is replaced by strange baryons, and even pure hyperonic species are expected to be bound. Though, the hypernuclear landscape remains largely unknown because of scarce constraints on the $NY$ and $YY$ interactions. We want to estimate the number of potentially bound hypernuclei. In order to evaluate realistic error bars within the theoretical uncertainties associated to the spherical mean-field approach, and the present information from already synthetized hypernuclei on the $N-Y$ and $Y-Y$ channels, we limit ourselves to …
We study strangeness dynamics in reactions relevant for the formation of multi-strange hypernuclei. In particular, we discuss the in-medium effects on elementary hyperon-nucleon ($YN$) channels, which are relevant for the production of hypernuclei at PANDA. The results indicate strong in-medium effects on $YN$-scattering, which might be important for hypernuclear studies at PANDA.
We present a simultaneous calculation of heavy single-$Λ$ hypernuclei and compact stars containing hypernuclear core within a relativistic density functional theory based on a Lagrangian which includes the hyperon octet and lightest isoscalar-isovector mesons which couple to baryons with density-dependent couplings. The corresponding density functional allows for SU(6) symmetry breaking and mixing in the isoscalar sector, whereby the departures in the $σ$-$Λ$ and $σ$-$Σ$ couplings away from their values implied by the SU(3) symmetric model are used to adjust the theory to the laboratory and as…
We describe full-coupled-channel ab initio calculations among the octet baryons for S=-2 s-shell hypernuclei,_{LambdaLambda}^4H,_{LambdaLambda}^5H and_{LambdaLambda}^6He. The wave function includes Lambda Lambda, Lambda Sigma, N Xi, and Sigma Sigma channels. Minnesota NN, D2^\prime YN and Nijmegen model D simulated YY interactions are used. This is the first attempt to explore the few-body problem of the full-coupled channel scheme for A=4-6, S=-2 multistrangeness hypernuclear systems. Bound state solutions of the Lambda Lambda hypernuclei,_{LambdaLambda}^4H,_{LambdaLambda}^5H and _{LambdaLamb…
We report the recent progress in relativistic mean-field (RMF) and beyond approaches for the low-energy structure of deformed hypernuclei. We show that the $Λ$ hyperon with orbital angular momentum $\ell=0$ (or $\ell>1$) generally reduces (enhances) nuclear quadrupole collectivity. The beyond mean-field studies of hypernuclear low-lying states demonstrate that there is generally a large configuration mixing between the two components $[^{A-1}Z (I^+) \otimes Λp_{1/2}]^J$ and $[^{A-1}Z (I\pm2 ^+) \otimes Λp_{3/2}]^J$ in the hypernuclear $1/2^-_1, 3/2^-_1$ states. The mixing weight increases as t…
The interpretation of hypernuclear gamma-ray data for p-shell hypernuclei in terms of shell-model calculations that include the coupling of Lambda- and Sigma-hypernuclear states is briefly reviewed. Next, Lambda 8Li, Lambda 8Be, and Lambda 9Li are considered, both to exhibit features of Lambda-Sigma coupling and as possible source of observed, but unassigned, hypernuclear gamma rays. Then, the feasibility of measuring the ground-state doublet spacing of Lambda 10Be, which, like Lambda 9Li, could be studied via the (K-,pi0 gamma) reaction, is investigated. Structural information relevant to the…
The $A$-dependence of the bond energy $ΔB_{ΛΛ}$ of the ${ΛΛ}$ hypernuclear ground states is calculated in a three-body ${Λ+ Λ+ {^{A}Z}}$ model and in the Skyrme-Hartree-Fock approach. Various ${ΛΛ}$ and $Λ$-nucleus or ${ΛN}$ potentials are used and the sensitivity of $ΔB_{ΛΛ}$ to the interactions is discussed. It is shown that in medium and heavy ${ΛΛ}$ hypernuclei, $ΔB_{ΛΛ}$ is a linear function of $r_Λ^{-3}$, where $r_Λ$ is rms radius of the hyperon orbital. It looks unlikely that it will be possible to extract ${ΛΛ}$ interaction from the double-$Λ$ hypernuclear energies only, the additional…
We present an overview of a fully covariant formulation of describing the hypernuclear production with hadronic and electromagnetic probes. This theory is based on an effective Lagrangian picture and it focuses on production amplitudes that are described via creation, propagation and decay into relevant channel of N*(1650), N*(1710) and N*(1720) intermediate baryonic resonance states in the initial collision of the projectile with one of the target nucleons. The bound state nucleon and hyperon wave functions are obtained by solving the Dirac equation with appropriate scalar and vector potentia…
Because of Pauli suppression effects the $Nπ$ decay of the free $Λ$ is not of importance in hypernuclei with $A\geq 10$. Rather the decay of such hypernuclei proceeds via the nucleon-stimulated mode $ΛN\rightarrow NN$, analysis of which presents a considerable theoretical challenge and about which there exists only a limited amount of experimental information. Herein we confront existing data wih various theoretical analyses which have been developed.
Hyperon-Nucleon Interaction Constrained by Light Hypernuclei
针对超子-核子相互作用低能常数约束不足的问题，提出利用p壳超核实验数据优化相互作用，解决了超子分离能高估问题并改进了$_Λ$He同位素链描述，还通过机器学习工具量化了多体层面的不确定性。
Unitary transformations of a Hamiltonian generally induce interaction terms beyond the particle rank present in the untransformed Hamiltonian that have to be captured and included in a many-body calculation. In systems with strangeness such as hypernuclei, the three-body terms induced by the hyperon-nucleon interaction are strong, so their inclusion is crucial. We present in detail a procedure for computing hyperon-nucleon-nucleon interaction terms that are induced during a similarity renormalization group (SRG) flow. The SRG is carried out in a basis spanned by antisymmetric harmonic-oscillat…
Several aspects about $Λ$-hypernuclei in the relativistic mean field theory, including the effective $Λ$-nucleon coupling strengths based on the successful effective nucleon-nucleon interaction PK1, hypernuclear magnetic moment and $\barΛ$-hypernuclei, have been presented. The effect of tensor coupling in $Λ$-hypernuclei and the impurity effect of $\barΛ$ to nuclear structure have been discussed in detail.
Variational study of Light Hypernuclei
该研究通过变分蒙特卡洛方法，利用现实及唯象相互作用计算轻Λ超核，揭示ΛN和ΛNN相互作用对超核稳定性的关键作用。
We apply the generator coordinate method (GCM) to single-$Λ$ hypernuclei in order to discuss the spectra of hypernuclear low-lying states. To this end, we use the same relativistic point-coupling energy functional both for the mean-field and the beyond-mean-field calculations. This relativistic GCM approach provides a unified description of low-lying states in ordinary nuclei and in hypernuclei, and is thus suitable for studying the $Λ$ impurity effect. We carry out an illustrative calculation for the low-lying spectrum of $^{21}_Λ$Ne, in which the interplay between the hypernuclear collective…
Charmed hypernuclei within density-dependent relativistic mean-field theory
本文基于DDRMF理论导出两套$Λ_c N$有效相互作用，系统研究了粲$Λ_{c}^{+}$超核的存在性及体性质，发现重排项与库仑排斥分别主导轻、重超核稳定性，强调有限密度下相互作用约束的重要性。
Neural-network excited states of $A=4$ nuclei and hypernuclei
利用神经网络量子态框架，通过重叠惩罚和自然激发态方法计算低激发谱，并引入量子数定位技术处理超核自旋污染，首次从头计算了$^{4}_\Lambda\mathrm{H}$的$M1$跃迁强度。
We extend the recently developed Jacobi no-core shell model to hypernuclei. Based on the coefficients of fractional parentage for ordinary nuclei, we define a basis where the hyperon is the spectator particle. We then formulate transition coefficients to states that single out a hyperon-nucleon pair which allow us to implement a hypernuclear many-baryon Hamiltonian for $p$-shell hypernuclei. As a first application, we use the basis states and the transition coefficients to calculate the ground states of $^{4}_Λ$He, $^{4}_Λ$H, $^{5}_Λ$He, $^{6}_Λ$He, $^{6}_Λ$Li, and $^{7}_Λ$Li and, additionally…
The density dependent relativistic hadron field theory is used to describe single particle properties of Lambda hypernuclei. The discussion focuses on the spin-orbit systematics in the relativistic mean-field formalism by discussing general effects of the Lambda continuum threshold and the delocalization of the Lambda wave function. Theoretical predictions for the hypernuclear Auger effect are presented.
In nuclear reactions of high energy one can simultaneously produce a lot of hypernuclei after the capture of hyperons by nuclear residues. We consider statistical disintegration of such hypernuclear systems and the connection of fragment production with the binding energies of hyperons. It is demonstrated that the hyperon binding energies can be effectively evaluated from the yields of different isotopes of hypernuclei. The double ratio method is suggested for this purpose. The advantage of this procedure is its universality and the possibility to involve many different isotopes. This method c…
The weak nonmesonic decay of Lambda-hypernuclei is studied in the context of a one-meson-exchange model. Predictions are made for the decay rate, p/n stimulation ratio and the asymmetry in polarized hypernuclear decay.
We address the $Λ$-hypernuclear `overbinding problem' in light hypernuclei which stands for a 1--3 MeV excessive $Λ$ separation energy calculated in $_Λ^5$He. This problem arises in most few-body calculations that reproduce ground-state $Λ$ separation energies in the lighter $Λ$ hypernuclei within various hyperon-nucleon interaction models. Recent pionless effective field theory nuclear few-body calculations are extended in this work to $Λ$ hypernuclei. At leading order, the $ΛN$ low-energy constants are associated with $ΛN$ scattering lengths and the $ΛNN$ low-energy constants are fitted to $…
Faddev calculations are reported for Lambda-Lambda-5H, Lambda-Lambda-5He and Lambda-Lambda-6He in terms of two Lambda hyperons plus the respective nuclear clusters, using Lambda-Lambda central potentials considered in past non-Faddeev calculations of Lambda-Lambda-6He. The convergence with respect to the partial-wave expansion is studied, and comparison is made with some of these Lambda-Lambda hypernuclear calculations. The Lambda-Lambda <--> Xi-N mixing effect is briefly discussed.
The production and structure of Λ hypernuclei are investigated in field theoretical models. The production in coherent p+A reactions is investigated by means of a resonance model. Results of exploratory calculations for associated strangeness production are presented for proton reactions on 40Ca. The target single particle wave functions are obtained from DDRH theory with density dependent Dirac-Brueckner meson-baryon vertices. The dependence of the in-medium vertices on density is discussed.
We study strangeness-changing response functions as an alternative description of hypernuclear structure. Hypernuclear states are treated in the same manner as any other conventional nuclear excitation that emerges from the response of the nuclear ground state to an external probe. The nuclear response is calculated using a random-phase approximation to an effective relativistic mean-field model that reproduces bulk properties of normal nuclei. The relevant meson-baryon vertices are constrained by imposing SU(3)-flavor symmetry, while the residual hyperon-particle - nucleon-hole interaction is…
A previously derived relativistic energy density functional for nuclei, based on low-energy in-medium chiral dynamics, is generalized to implement constraints from chiral SU(3) effective field theory and applied to $Λ$ hypernuclei. Density-dependent central and spin-orbit mean fields are calculated for a $Λ$ hyperon using the SU(3) extension of in-medium chiral perturbation theory to two-loop order. Long range $ΛN$ interactions arise from kaon-exchange and from two-pion-exchange with a $Σ$ hyperon in the intermediate state. Short-distance dynamics is encoded in contact interactions. They inclu…
In the last years auxiliary field diffusion Monte Carlo has been used to assess the properties of hypernuclear systems, from light- to medium-heavy hypernuclei and hyper-neutron matter. One of the main findings is the key role played by the three-body hyperon-nucleon-nucleon interaction in the determination of the hyperon separation energy of hypernuclei and as a possible solution to the hyperon puzzle. However, there are still aspects of the employed hypernuclear potential that remain to be carefully investigated. In this paper we show that the isospin dependence of the Lambda-NN force, which…
Precision Hypernuclear Structure from Interaction Cross Sections
利用耦合道Glauber理论和三体波函数，理论证明相互作用截面测量可高灵敏度地确定超氚核的物质半径和Λ分离能。
New Faddeev-Yakubovsky calculations for light Lambda-Lambda hypernuclei are presented in order to assess the self consistency of the Lambda-Lambda hypernuclear binding-energy world data and the implied strength of the Lambda-Lambda interaction, in the wake of recent experimental reports on Lambda-Lambda-4H and Lambda-Lambda-6He. Using Gaussian soft-core simulations of Nijmegen one-boson-exchange model interactions, the Nijmegen soft-core model NSC97 simulations are found close to reproducing the recently reported binding energy of Lambda-Lambda-6He, but not those of other species. For stranger…
Single- and Double-$Λ$ Hypernuclear Correlations Calibrate $ΛΛ$ Interaction Energies
利用单Λ和双Λ超核的结合能线性关联，通过统计评估方法校准ΛΛ相互作用能，发现直接相对论密度泛函预测可能低估ΛΛ关联。
The work presents the recent developments in Quantum Monte Carlo calculations for nuclear systems including strange degrees of freedom. The Auxiliary Field Diffusion Monte Carlo algorithm has been extended to the strange sector by the inclusion of the lightest among the hyperons, the $Λ$ particle. This allows to perform detailed calculations for $Λ$ hypernuclei, providing a microscopic framework for the study of the hyperon-nucleon interaction in connection with the available experimental information. The extension of the method for strange neutron matter, put the basis for the first Diffusion…
We employ a feed-forward artificial neural network to extrapolate at large model spaces the results of {\it ab-initio} hypernuclear No-Core Shell Model calculations for the $Λ$ separation energy $B_Λ$ of the lightest hypernuclei, $^3_Λ$H, $^4_Λ$H and $^4_Λ$He, obtained in computationally accessible harmonic oscillator basis spaces using chiral nucleon-nucleon, nucleon-nucleon-nucleon and hyperon-nucleon interactions. The overfitting problem is avoided by enlarging the size of the input dataset and by introducing a Gaussian noise during the training process of the neural network. We find that a…
We present a detailed formalism of the microscopic particle-rotor model for hypernuclear low-lying states based on a covariant density functional theory. In this method, the hypernuclear states are constructed by coupling a hyperon to low-lying states of the core nucleus, which are described by the generator coordinate method (GCM) with the particle number and angular momentum projections. We apply this method to study in detail the low-lying spectrum of $^{13}_{~Λ}$C and $^{21}_{~Λ}$Ne hypernuclei. We also briefly discuss the structure of $^{155}_{~~Λ}$Sm as an example of heavy deformed hyper…
We have systematically investigated the excitation spectra of $p$-shell hypernuclei within the shell model based on the nucleon-nucleon and hyperon-nucleon interactions. For the effective nucleon-nucleon interaction, we adopt the Gogny force instead of the widely-used empirical $p$-shell Cohen-Kurath interaction, while the hyperon-nucleon interaction takes the $ΛN$ interaction including the $ΛN$-$ΣN$ coupling effect. We find that the shell model with the Gogny force can give reasonable descriptions of both spectra and binding energies of the $p$-shell nuclei. With this confidence, combined wit…
The characteristic and selective nature of the electro-magnetic production of Lambda-hypernuclei in exciting states is demonstrated assuming the medium-mass targets 28Si, 40Ca, and 52Cr. Formalism of DWIA is used adopting the Saclay-Lyon, Kaon-MAID, Adelseck-Saghai, and Williams-Ji-Cotanch models for the elementary amplitudes and various nuclear and hypernuclear wave functions. The elementary amplitudes are discussed in detail presenting their basic properties and comparison with data. The unique features of the electro-magnetic production of Lambda-hypernuclei shown on examples are the slecti…
We introduce a mean field model based on realistic 2-body baryon interactions and calculate spectra of a set of p-shell and sd-shell Λ hypernuclei - 13ΛC, 17ΛO, 21ΛNe, 29ΛSi and 41ΛCa. The hypernuclear spectra are compared with the results of a relativistic mean field (RMF) model and available experimental data. The sensitivity of Λ single-particle energies to the nuclear core structure is explored. Special attention is paid to the effect of spin-orbit ΛN interaction on the energy splitting of the Λ single particle levels 0p3/2 and 0p1/2. In particular, we analyze the contribution of the symme…
Halo Structures in p-Shell Hypernuclei with Natural Orbitals
本文利用自然轨道方法研究p壳超核中的核子和超子晕结构，通过无芯壳模型计算揭示了ΛHe5中的超子晕特征。
Two different approaches have been employed for the evaluation of the decay widths of Lambda-hypernuclei (ranging from $^5_Λ$He to $^{208}_Λ$Pb) with the polarization propagator method. In ref.[1], the two-nucleon stimulated non-mesonic decay, $ΛNN\to NNN$, has been parameterized phenomenologically by means of data on the pion-nucleus optical potential. The other approach [2] consisted in a fully microscopic description of the non-mesonic decays through the first order approximation of the so-called bosonic-loop-expansion. Both calculations reproduce, with approximately the same accuracy, the …
We develop a method for calculating the doublet splittings of select ground-state single $Λ$-hypernuclei. This hypernuclear spectroscopy is conducted by supplementing the self-consistent single-particle equations with an effective interaction, which follows directly from the underlying lagrangian,to simulate the residual particle-hole interaction. Our previous investigation, performed using only the leading-order contributions to the particle-hole interaction, was inadequate. In the present work, this method is improved upon by increasing the level of truncation in the residual interaction to …
Hypernuclear structure with the new leading order covariant chiral hyperon-nucleon force
本文利用次领头阶协变手征超子-核子力构建微观Λ-N相互作用，在无自由参数条件下成功重现轻到重质量单Λ超核的结合能，验证了该势的有效性并为Skyrme-Hartree-Fock框架提供了实用微观相互作用。
The contribution of Pauli exchange terms to the two--nucleon induced non--mesonic weak decay of $^{12}_Λ$C hypernuclei, $ΛNN\to nNN$ ($N=n$ or $p$), is studied within a nuclear matter formalism implemented in a local density approximation. We have adopted a weak transition potential including the exchange of the complete octets of pseudoscalar and vector mesons as well as a residual strong interaction modeled on the Bonn potential. The introduction of exchange terms turns out to reduce the two--nucleon induced non--mesonic rate by 18% and, jointly with an increase in the one--nucleon induced r…
The energies of p-shell hypernuclear gamma rays obtained from recent experiments using the Hyperball at BNL and KEK are used to constrain the YN interaction which enters into shell-model calculations that include both Lambda and Sigma configurations.
Empirical data on the spectra of light hypernuclei, especially the data from recent gamma-ray experiments, is used to constrain the parameters which govern the p(nucleon)s(Lambda) and p(nucleon)p(Lambda) two-body matrix elements that enter into shell-model calculations.
$Λ$ and $Σ$ potentials in neutron stars, hypernuclei, and heavy-ion collisions
该研究基于手征有效场论的超子力，验证了高密度下呈强排斥性的$Λ$势与超核、重离子碰撞数据的一致性，并证明可通过调节$YNN$力低能常数同时抑制中子星中$Λ$的出现与重现$Σ$势经验值，为解决中子星超子疑难提供支持。
New Faddeev-Yakubovsky calculations are reported for Lambda-Lambda-6He and Lambda-Lambda-10Be in terms of clusters of alpha's and Lambda's, using Lambda-Lambda s-wave potentials motivated by several of the Nijmegen model interactions. The self consistency of the Lambda-Lambda hypernuclear world data for these species is discussed. The newly reported Lambda-Lambda-6He event is found to be compatible with Lambda-Lambda interaction strengths provided by the Nijmegen soft-core one-boson-exchange model NSC97. Faddeev calculations for Lambda-Lambda-5H and Lambda-Lambda-5He suggest that these Lambda-…
The hypernuclear systems $NNΞ$ and $ΞΞN$ are considered as an analogue of $nnp$ ($^3$H) nuclear system (with the notation as $AAB$ system). We use the recently proposed modification for the $s$-wave Malfliet-Tjon potential. The modification simulates the Extended-Soft-Core model (ESC08c) for baryon-baryon interactions. The $ΞN$ spin/isospin triplet $(S, I)=(1, 1)$ potential generates a bound state with the energy $B_2(AB)$=1.56~MeV. Three-body binding energy $B_3$ for the states with maximal total isospin is calculated employing the configuration-space Faddeev equations. Comparison with the re…
A previously introduced relativistic energy density functional, successfully applied to ordinary nuclei, is extended to hypernuclei. The density-dependent mean field and the spin-orbit potential are consistently calculated for a $Λ$ hyperon in the nucleus using the SU(3) extension of in-medium chiral perturbation theory. The leading long range $ΛN$ interaction arises from kaon-exchange and $2π$-exchange with $Σ$ hyperon in the intermediate state. Scalar and vector mean fields reflecting in-medium changes of the quark condensates are constrained by QCD sum rules. The model, applied to oxygen as…
A consistent microscopic diagrammatic approach is applied for the first time to the calculation of the nucleon emission spectra in the non-mesonic weak decay of Lambda-hypernuclei. We adopt a nuclear matter formalism extended to finite nuclei via the local density approximation, a one--meson exchange weak transition potential and a Bonn nucleon-nucleon strong potential. Ground state correlations and final state interactions, at second order in the nucleon--nucleon interaction, are introduced on the same footing for all the isospin channels of one- and two-nucleon induced decays. Single and dou…
The Density Dependent Relativistic Hadron Field (DDRH) theory, previously introduced and applied to isospin nuclei, is extended to hypernuclei by including the octet hyperons. Infinite matter Dirac-Brueckner theory for octet baryons and the derivation of in-medium DDRH baryon-meson vertices is discussed. From the properties of Dirac-Brueckner interactions it is found that hyperon and nucleon self-energies and vertices are related by the ratios of free space coupling constants. This leads to simple scaling laws for the in-medium hyperon and nucleon vertices. The model is applied in relativistic…
We evaluate pionic decay widths of Lambda hypernuclei using a shell model for, both the nuclear bound and the continuum nucleon wave functions in the final state, and distorted waves for the outgoing pion. An excellent agreement with the recent KEK measurement of $π^-$-decay widths of $^{12}_Λ$C and $^{28}_Λ$Si is found. Besides, results for $^{56}_Λ$Fe are consistent with the existing upper bound.
We study the photoproduction of the ^12{_Lambda}B hypernucleus within a fully covariant effective Lagrangian based model, employing Lambda bound state spinors derived from the latest quark-meson coupling model. The kaon production vertex is described via creation, propagation and decay of N*(1650), N*(1710), and N*(1720) intermediate baryonic resonant states in the initial collision of the photon with a target proton in the incident channel. The parameters of the resonance vertices are fixed by describing the total and differential cross section data on the elementary gamma (p, K+) Lambda reac…
In this work we outline a program for lattice QCD that would provide a first step toward understanding the strong and weak interactions of strange baryons. The study of hypernuclear physics has provided a significant amount of information regarding the structure and weak decays of light nuclei containing one or two Lambda's, and Sigma's. From a theoretical standpoint, little is known about the hyperon-nucleon interaction, which is required input for systematic calculations of hypernuclear structure. Furthermore, the long-standing discrepancies in the P-wave amplitudes for nonleptonic hyperon d…
Energy spectra of $0s$-orbit $Λ$ states in $p$-shell $Λ$ hypernuclei ($^{A}_ΛZ$) and those in $^{19}_Λ\textrm{F}$ are studied with the microscopic cluster model and antisymmetrized molecular dynamics using the $G$-matrix effective $ΛN$ ($ΛNG$) interactions. Spin-dependent terms of the ESC08a version of the $ΛNG$ interactions are tested and phenomenologically tuned to reproduce observed energy spectra in $p$-shell $^{A}_ΛZ$. Spin-dependent contributions of the $ΛN$ interactions to spin-doublet splitting and excitation energies are discussed. Energy spectra for unobserved excited states in $p$-s…
We compute for the first time the decay width of lambda-hypernuclei in a relativistic mean-field approximation to the Walecka model. Due to the small mass difference between the lambda-hyperon and its decay products---a nucleon and a pion---the mesonic component of the decay is strongly Pauli blocked in the nuclear medium. Thus, the in-medium decay becomes dominated by the non-mesonic, or two-body, component of the decay. For this mode, the lambda-hyperon decays into a nucleon and a spacelike nuclear excitation. In this work we concentrate exclusively on the pion-like modes. By relying on the …
Variational calculations for s-shell hypernuclei are performed by explicitly including $Σ$ degrees of freedom. Four sets of YN interactions (SC97d(S), SC97e(S), SC97f(S) and SC89(S)) are used. The bound-state solution of $_Λ^5$He is obtained and a large energy expectation value of the tensor $ΛN-ΣN$ transition part is found. The internal energy of the $^4$He subsystem is strongly affected by the presence of a $Λ$ particle with the strong tensor $ΛN-ΣN$ transition potential.
Variational study of s-shell lambda hypernuclear system
针对超子-核子、超子-超子相互作用实验数据匮乏的问题，采用变分蒙特卡洛技术分析不同两体、三体相互作用及λ-λ势对s壳层超核系统结合能的影响，为相关相互作用研究提供理论支撑。
Few-body $Λ$ hypernuclei provide valuable information towards understanding strange matter. Recent experimental progress by the STAR Collaboration at the RHIC facility and by the ALICE Collaboration at the LHC has been matched by theoretical progress reviewed here: (i) lifetimes of the hypertriton $_Λ^3$H, $_Λ^3$n if particle-stable, $_Λ^4$H and $_Λ^4$He and their charge symmetry breaking, and (ii) the onset of $ΛΛ$ hypernuclear binding.
We investigate the production of a cascade hyperon ($Ξ$) and bound $Ξ^-$ hypernuclei in the $(K^-,K^+)$ reaction on proton and nuclear targets, respectively, within a covariant effective Lagrangian model. The $K^+Ξ^-$ production vertex is described by excitation, propagation and decay of $Λ$ and $Σ$ resonance states in the initial collision of a $K^-$ meson with a free or bound proton in the incident channel. The parameters of the resonance vertices are taken from previous studies and SU(3) symmetry considerations. The model is able to provide a good description of the available data on total …
$0s$-orbit $Λ$ states in $p$-shell double-$Λ$ hypernuclei ($^{\ \,A}_{ΛΛ}Z$), $^{\ \,8}_{ΛΛ}\textrm{Li}$, $^{\ \,9}_{ΛΛ}\textrm{Li}$, $^{10,11,12}_{\ \ \ \ \ ΛΛ}\textrm{Be}$, $^{12,13}_{\ \ ΛΛ}\textrm{B}$, and $^{\,14}_{ΛΛ}\textrm{C}$ are investigated. Microscopic cluster models are applied to core nuclear part and a potential model is adopted for $Λ$ particles. The $Λ$-core potential is a folding potential obtained with effective $G$-matrix $Λ$-$N$ interactions, which reasonably reproduce energy spectra of $^{A-1}_{\,Λ}Z$. System dependence of the $Λ$-$Λ$ binding energies is understood by the…
In order to clarify the nature of hypernuclear low-lying states, we carry out a comprehensive study for the structure of $^{144-154}_{~~~~~~~~Λ}$Sm-hypernuclei, which exhibit a transition from vibrational to rotational characters as the neutron number increases. To this end, we employ a microscopic particle-core coupling scheme based on a covariant density functional theory. We find that the positive-parity ground-state band in the hypernuclei shares a similar structure to that of the corresponding core nucleus. That is, regardless of whether the core nucleus is spherical or deformed, each hyp…
Multi-strangeness matter from ab initio calculations
本文结合核晶格有效场论与新型辅助场QMC算法，实现无符号问题的多奇异重子系统从头计算，统一解释超核、超核物质状态方程及中子星观测性质。
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