本文在 chiral effective field theory 中首次一致引入 chiral $Λ$NN 和 $Σ$NN 三体力，基于 no-core shell model 计算了轻 $Λ$ hypernuclei 的分离能，发现考虑 YNN 三体力能较好再现实验值。
摘要：
本文介绍了在 chiral effective field theory 中对轻 $Λ$ hypernuclei 的研究。首次一致地引入了 chiral $Λ$NN 和 $Σ$NN 三体力。计算在 no-core shell model 内进行。给出了 hypernuclei $^3_Λ\mathrm{H}$、$^4_Λ\mathrm{H}$/$^4_Λ\mathrm{He}$、$^5_Λ\mathrm{He}$ 和 $^7_Λ\mathrm{Li}$ 的分离能结果。发现一旦考虑 YNN 三体力，实验值就能被相当好地再现。
英文摘要：
A study of light $Λ$ hypernuclei in chiral effective field theory is presented. For the first time chiral $Λ$NN and $Σ$NN three-body forces are included consistently. The calculations are performed within the no-core shell model. Results for the separation energies of the hypernuclei $^3_Λ\mathrm{H}$, $^4_Λ\mathrm{H}$/$^4_Λ\mathrm{He}$, $^5_Λ\mathrm{He}$, and $^7_Λ\mathrm{Li}$ are given. It is found that the experimental values can be fairly well reproduced once YNN three-body forces are taken into account.
Background: The calculation of the hyperon binding energy in hypernuclei is crucial to understanding the interaction between hyperons and nucleons. Purpose: We assess the relative importance of two- and three-body hyperon-nucleon force by studying the effect of the hyperon-nucleon-nucleon interaction in closed shell Λ-hypernuclei from A=5 to 91. Methods: The Λ-binding energy has been calculated using the auxiliary field diffusion Monte Carlo method for the first time, to study light and heavy hypernuclei within the same model. Results: Our results show that including a three-body component in …
Within the microscopic transport, systematic investigation of the many facets of hyperons and hypernuclei up to strangeness $S = -2$ are carried out for $^{197}$Au + $^{197}$Au and $^{40}$Ca + $^{40}$Ca at the incident energy of $3A$ GeV. The spatial, temporal and density distributions of hyperon production, absorption and freeze-out are thoroughly investigated. The rapidity and kinetic energy spectra of $Ξ$ hyperons and double $Λ$ hypernuclei are analyzed. It is revealed that the chemical balance of hyperon production is established in baryon-baryon channels while the opposite is found in bar…
We report quantum Monte Carlo calculations of single-$Λ$ hypernuclei for $A<50$ based on phenomenological two- and three-body hyperon-nucleon forces. We present results for the $Λ$ separation energy in different hyperon orbits, showing that the accuracy of theoretical predictions exceeds that of currently available experimental data, especially for medium-mass hypernuclei. We show the results of a sensitivity study that indicates the possibility to investigate the nucleon-isospin dependence of the three-body hyperon-nucleon-nucleon force in the medium-mass region of the hypernuclear chart, whe…
The density dependent relativistic hadron (DDRH) theory is introduced as an effective field theory for nuclei and hypernuclei. A Dirac-Brueckner approach to in-medium nucleon-hyperon interactions is presented. Density dependent meson-baryon vertices are determined from DBHF self-energies in infinite matter. Scaling laws for hyperon vertices are derived from a diagrammatic analysis of self-energies. In a local density approximation the DB vertices are applied in relativistic DDRH Hartree calculations to finite hypernuclei. Lambda single particle spectra and spin-orbit splittings are described r…
We investigate the role of two- and three-body $Λ$-nucleon forces by computing the ground state of a few $Λ$-hypernuclei with the Auxiliary Field Diffusion Monte Carlo algorithm. Calculations have been performed for masses up to A=41, including some open-shell hypernuclei. The results show that the use of a bare hyperon-nucleon force fitted on the available scattering data yields a consistent overestimate of the $Λ$-separation energy $B_Λ$. The inclusion of a hyperon-nucleon-nucleon interaction systematically reduces $B_Λ$, leading to a qualitatively good agreement with experimental data over …
The hypernuclei $^4_Λ$He and $^4_Λ$H provide important information on the hyperon-nucleon interaction. We present accurate Faddeev-Yakubovsky calculations for the $Λ$ separation energies of the $0^+$ ground and the $1^+$ excited states based on the Nijmegen SC YN interactions. We explicitly take the $Σ$ admixture into account. Mass differences of the baryons and the charge-dependence of the interaction are considered. The results show that the Nijmegen models cannot predict all separation energies simultaneously hinting to failures of the current interaction models.
The likely presence of $Λ$ baryons in dense hadronic matter tends to soften the equation of state to an extend that the observed heaviest neutron stars are difficult to explain. We analyze this "hyperon problem" with a phenomenological approach. First, we review what can be learned about the interaction of $Λ$ particle with dense matter from the observed hypernuclei and extend this phenomenological analysis to asymmetric matter. We add to this the current knowledge on non-strange dense matter, including its uncertainties, to conclude that the interaction between $Λ$s and dense matter has to be…
Hypernuclei have been studied within the framework of Relativistic Mean Field theory. The force FSU Gold has been extended to include hyperons. The effective hyperon-nucleon and nucleon-nucleon interactions have been obtained by fitting experimental energies in a number of hypernuclei over a wide range of mass. Calculations successfully describe various features including hyperon separation energy and single particle spectra of single-Λhypernuclei throughout the periodic table. We also extend this formalism to double-Λhypernuclei.
The structure of single-$Λ$ hypernuclei is studied using the chiral hyperon-nucleon potentials derived at leading order (LO) and next-to-leading order (NLO) by the Jülich--Bonn--Munich group. Results for the separation energies of $Λ$ single-particle states for various hypernuclei from $^5_Λ$He to $^{209}_{\,\,\,\,\,Λ}$Pb are presented for the LO interaction and the 2013 (NLO13) and 2019 (NLO19) versions of the NLO potentials. It is found that the results based on the LO potential show a clear tendency for overbinding while those for the NLO13 interaction underbind most of the considered hyper…
Properties of hypernuclei $_{ΛΛ}^5$H and $_{ΛΛ}^5$He are studied in a two-channel approach with explicit treatment of coupling of channels ^3\text{Z}+Λ+Λand α+Ξ. Diagonal ΛΛand coupling ΛΛ-ΞN interactions are derived within G-matrix procedure from Nijmegen meson-exchange models. Bond energy ΔB_{ΛΛ} in $_{ΛΛ}^5$He exceeds significantly that in $_{ΛΛ}^5$H due to the channel coupling. Diagonal Ξαattraction amplifies the effect, which is sensitive also to Λ-core interaction. The difference of the ΔB_{ΛΛ} values can be an unambiguous signature of the ΛΛ-ΞN coupling in ΛΛhypernuclei. However, improv…
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 …
Four-body Faddeev-Yakubovsky calculations for Lambda-Lambda-p-n do not produce a bound state for Lambda-Lambda hydrogen 4, although suitably defined three-body Faddeev calculations for Lambda-Lambda-d produce a 1+ bound state for Lambda-Lambda interactions fitted to the Lambda-Lambda helium 6 emulsion event from KEK E373. This is opposite to the normal situation where a four-body Faddeev-Yakubovsky calculation yields stronger binding than that due to a suitably defined three-body Faddeev calculation. For stranger systems, Faddeev calculations using Lambda-Xi interactions which simulate the Nij…
Shapes of light normal nuclei and $Λ$-hypernuclei are investigated using relativistic mean field approach. The FSUGold parametrization is used for this purpose. The addition of a $Λ$ is found to change the shape of the energy surface towards prolate. The deformation in a $Λ$-hypernucleus, when the hyperon is in the first excited state, is also discussed. The effect of the inclusion of the hyperon on the nuclear radius is generally small with one exception.
We study the properties of double-$Λ$ hypernuclei in the relativistic mean-field theory, which has been successfully used for the description of stable and unstable nuclei. With the meson-hyperon couplings determined by the experimental binding energies of single-$Λ$ hypernuclei, we present a self-consistent calculation of double-$Λ$ hypernuclei in the relativistic mean-field theory, and discuss the influence of hyperons on the nuclear core. The contribution of two mesons with dominant strange quark components (scalar $σ^*$ and vector $ϕ$) to the $ΛΛ$ binding energy of double-$Λ$ hypernuclei i…
The relativistic nucleus-nucleus collisions can produce hypernuclei and low-temperature hyper-matter as a result of hyperon capture by nuclear residues and free nucleons. We use the transport, coalescence and statistical models to describe the whole process, and point at the important advantages of such reactions: A broad variety of formed hypernuclei in masses and isospin allows for investigating properties of exotic hypernuclei, as well as the hypermatter both at high and low temperatures. The abundant production of multi-strange nuclei that can give an access to multi-hyperon systems and st…
We extend the relativistic Hartree-Fock (RHF) theory to study the structure of single-$Λ$ hypernuclei. The density dependence is taken in both meson-nucleon and meson-hyperon coupling strengths, and the induced $Λ$-nucleon ($ΛN$) effective interactions are determined by fitting $Λ$ separation energies to the experimental data for several single-$Λ$ hypernuclei. The equilibrium of nuclear dynamics described by the RHF model in normal atomic nuclei, namely, the balance between nuclear attractive and repulsive interactions, is then found to be drastically changed in single-$Λ$ hypernuclei, reveal…
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…
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 decays of hyperons and hypernuclei are studied from the chiral symmetry viewpoint. The soft pion relations are useful in understanding the isospin properties of the weak hyperon decays. Recent development on the short-range part of the $\Lam N\to NN$ weak transitions shows fairly good account of the weak decays of hypernuclei, though it fails to explain the $n/p$ ratio. The $\pip$ decays of light hypernuclei are studied in the soft pion approach. They are related to the $\DI=3/2$ amplitudes of the nonmesonic decay.
The question of the competition between $Λ$ and $Ξ^{0,-}$ in the ground-state of multi-strange hypernuclei is addressed within a non-relativistic density functional approach, partially constrained by ab-initio calculations and experimental data. The exploration of the nuclear chart for $10<Z<120$ as a function of the strangeness number is performed by adding hyperons to a nuclear core imposing either conserved total charge $Q$ or conserved proton number $Z$. We find that almost all $Λ$ hypernuclei present an instability with respect to the strong interaction decay of $Λ$ towards $Ξ^{0,-}$ and …
Single--particle spectra of $Λ$ and $Σ$ hypernuclei are calculated within a relativistic mean--field theory. The hyperon couplings used are compatible with the $Λ$ binding in saturated nuclear matter, neutron-star masses and experimental data on $Λ$ levels in hypernuclei. Special attention is devoted to the spin-orbit potential for the hyperons and the influence of the $ρ$-meson field (isospin dependent interaction).
In this paper, we calculated the binding energy per baryon of the $Λ$ hypernuclei systemically, using the relativistic mean field theory (RMF) in a statistic frame. Some resemble properties are found among most of the hypernuclei found in experiments. The data show that a $Λ$ hypernucleus will be more stable, if it is composed of a $Λ$ hyperon adding to a stable normal nuclear core, or a $Λ$ hyperon replacing a neutron in a stable normal nuclear core. According to our calculations, existences of some new $Λ$ hypernuclei are predicted under the frame of RMF.
In this paper, we presented the ground state energies calculated for some single and double cascade hyperon($Ξ^{-}$) hypernuclei. For hypernuclei of the type $_Ξ^{A_c+1}$X we applied $Ξ+^A_c$X two-body model and for hypernuclei of the type $_{ΞΞ}^{A_c+2}$X we adopted $Ξ+Ξ+^A_c$X three-body model. A two-term Gaussian (Isle type) potential with adjustable parameters is chosen as the $Ξ$-nucleus interaction, while a two-term Yukawa-type potential has been chosen for the $ΞΞ$ pair. In the three-body model calculation, we adopted the hyperspherical harmonics expansion (HHE) formalism. The resulting…
The stiff equation of state (EoS) giving the neutron-star mass of $2M_{\odot}$ suggests the existence of strongly repulsive many-body effect (MBE) not only in nucleon channels but also in hyperonic ones. As a specific model for MBE, the repulsive multi-pomeron exchange potential (MPP) is added to the two-body interaction together with the phenomenological three-body attraction. For various versions of the Nijmegen interaction models, the MBE parts are determined so as to reproduce the observed data of $B_Λ$. The mass dependence of $B_Λ$ values is shown to be reproduced well by adding MBE with …
The relativistic mean-field theory with Green's function method is extended to study $Λ$ hypernuclei. Taking hypernucleus $^{61}_Λ$Ca as an example, the single-particle resonant states for $Λ$ hyperons are investigated by analyzing density of states and the corresponding energies and widths are given. Different behaviors are observed for the resonant states, i.e., the distributions of the very narrow $1f_{5/2}$ and $1f_{7/2}$ states are very similar as bound states while that of the wide $1g_{7/2}$ and $1g_{9/2}$ states are like scattering states. Besides, the impurity effect of $Λ$ hyperons o…
Pairing correlations play a very important role in atomic nuclei. Although several effective pairing interactions have been used in mean field calculations for nucleons, little is known about effective pairing interactions for hyperons. Based on the quark model, we propose a relationship between effective pairing interactions for hyperons and for nucleons; e.g., for $Λ$s, the strength of the pairing interaction is 4/9 of that for nucleons. A separable pairing force of finite range which has been widely applied to describing pairing correlations in normal nuclei is used to investigate pairing e…
A self-consistent description for hot $Λ$ hypernuclei in hypothetical big boxes is developed within the relativistic Thomas-Fermi approximation in order to investigate directly the liquid-gas phase coexistence in strangeness finite nuclear systems. We use the relativistic mean-field model for nuclear interactions. The temperature dependence of $Λ$ hyperon density, $Λ$ hyperon radius, excitation energies, specific heat, and the binding energies of $Λ$ hypernuclei from $^{16}_Λ$O to $^{208}_Λ$Pb in phase transition region are calculated by using the subtraction procedure in order to separate the…
The Non-Symmetrized Hyperspherical Harmonics method (NSHH) is introduced in the hypernuclear sector and benchmarked with three different ab-initio methods, namely the Auxiliary Field Diffusion Monte Carlo method, the Faddeev-Yakubovsky approach and the Gaussian Expansion Method. Binding energies and hyperon separation energies of three- to five-body hypernuclei are calculated by employing the two-body $Λ$N component of the phenomenological Bodmer-Usmani potential, and a hyperon-nucleon interaction simulating the scattering phase shifts given by NSC97f. The range of applicability of the NSHH me…
Simultaneous description of ordinary and hypernuclei masses by a single mass formula has been a great challenge in nuclear physics. Hyperon-separation energies of about forty Lambda($Λ$), three Lambda-Lambda($ΛΛ$), one Sigma($Σ$) and seven Cascade($Ξ$) hypernuclei have been experimentally found. Many of these nuclei are of light masses. We prescribe a new mass formula, called BWMH, which describes the normal and hypernuclei on the same footing. It is based on the modified-Bethe-Weizsäcker mass formula (BWM). BWM is basically an extension of the Bethe-Weizsäcker mass formula (BW) for light nucl…
Properties of $Λ,~Ξ^0$ hypernuclei and neutron stars are investigated in quark mean field model with pion and gluon corrections. Firstly, $u, ~d$, and $s$ quarks are confined by relativistic harmonic oscillator potentials to generate the baryons, like nucleon, $Λ, ~Σ$, and $Ξ$ hyperons. The effects of pion-quark coupling and one-gluon exchange are considered perturbatively. Then, the baryons interact with each other through exchanging $σ, ~ω,$ and $ρ$ mesons between quarks in hypernuclei and nuclear matter. The strengths of confinement potentials for $u, ~d,$ and $s$ quarks are determined by t…
The dynamics of light hypernuclei and nuclear clusters produced in $^{197}$Au+$^{197}$Au collisions has been investigated thoroughly with a microscopic transport model. All possible channels of hyperon production and transportation of hyperons in nuclear medium are implemented into the model. The light complex fragments are recognized with the Wigner density approach at the stage of freeze out in nuclear collisions. The isospin diffusion in the collisions is responsible for the neutron-rich cluster formation. The collective flows of nuclear clusters are consistent with the experimental data fr…
We study the binding energies, radii, single-particle energies, spin-orbit potential and density profile for multi-strange hypernuclei in the range of light mass to superheavy region within the relativistic mean field (RMF) theory. The stability of multi-strange hypernuclei as a function of introduced hyperons ($Λ$ and $Σ$) is investigated. The neutron, lambda and sigma mean potentials are presented for light to superheavy hypernuclei. The inclusion of hyperons affects the nucleon, lambda and sigma spin-orbit potentials significantly. The bubble structure of nuclei and corresponding hypernucle…
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…
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…
The production of strangeness on the nucleon and hyperon and hypernuclear production in heavy ion collisions at relativistic energies and in antiproton annihilation on nuclei is discussed. The reaction process is described by transport theory with focus on $S=-2$ channels and a comparison of different model interactions. The interactions of hyperons in nuclear matter is investigated in a novel SU(3) approach. An outlook to the $S=-3$ sector and $Ω^-$ physics is given.
Machine learning the single-$Λ$ hypernuclei with neural-network quantum states
Key Laboratory of Nuclear Physics and Ion-beam Application (MOE), Institute of Modern Physics, Fudan University（复旦大学现代物理研究所核物理与离子束应用教育部重点实验室）；State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University（北京大学物理学院核物理与技术国家重点实验室）；Graduate School of China Academy of Engineering Physics（中国工程物理研究院研究生部）；Shanghai Research Center for Theoretical Nuclear Physics, NSFC and Fudan University（上海理论核物理研究中心（国家自然科学基金委与复旦大学））
Theoretical estimations of production cross sections of light $Λ$ and $Σ$ hypernuclei in $(e,e'K^{+})$ reactions at around CEBAF energies are given. Because of dominant spin-flip amplitudes and large momentum transfers, unnatural parity states and stretched states of hypernuclei are favorably excited. They are compared with quasifree hyperon productions.
[Background] The hyperon impurity effect in nuclei has been extensively studied in different mean-field models. Recently, there is a controversy about whether the $Λ$ hyperon is more tightly bound in the normal deformed (ND) states than that in the superdeformed (SD) states.[Purpose] This article is aimed to provide a beyond-mean-field study of the low-lying states of hypernuclei with shape coexistence and to shed some light on the controversy.[Method] The models of relativistic mean-field and beyond based on a relativistic point-coupling energy functional are adopted to study the low-lying st…
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…
Using the Hartree-Fock plus random-phase-approximation (HF+RPA), we study the impurity effect of $Λ$ hyperon on the collective vibrational excitations of double-$Λ$ hypernuclei. To this end, we employ a Skyrme-type $ΛN$ and $ΛΛ$ interactions for the HF calculations, and the residual interactions for RPA derived with the same interactions. We find that inclusion of two $Λ$ hyperons in $^{16}$O shifts the energy of the collective states towards higher energies. In particular, the energy of the giant monopole resonance of $^{\,\,18}_{ΛΛ}$O, as well as that of $^{210}_{ΛΛ}$Pb, becomes larger. This…
In present study, we search the lambda magic number in hypernuclei within the framework of relativistic mean field theory (RMF) with inclusion of hyperon-nucleon and hyperon-hyperon potentials. Based on one- and two-lambda separation energy and two-lambda shell gap, 2, 8, 14, 18, 20, 28, 34, 40, 50, 58, 68, 70 and 82 are suggested to be the $Λ$ magic number within the present approach. The weakening strength of $Λ$ spin-orbit interaction is responsible for emerging the new lambda shell closure other than the model scheme. The predicted $Λ$ magic numbers are in remarkable agreement with earlier…
We investigate the properties of $Λ$ hyperon in $Λ$-hypernuclei using an effective nuclear density functional theory which is based on the low-energy effective field theory. It expands the energy density in the power of Fermi momentum, and consequently has multiple density dependence for the effective many-body interactions. Starting from the effective density functional for nucleons, we determine the parameters for the two- and many-body $Λ$-$N$ interactions added to the nucleon energy density functional by fitting to $Λ$-hypernuclear data. The experimental data consist of the energy levels o…
We study the superdeformed (SD) states and corresponding SD hypernuclei of Ar isotopes with the multidimensionally-constrained relativistic mean field (MDC-RMF) models which can accommodate various shape degree of freedom. %The hyperon-nucleon $σ$-$Λ$ and $ω$-$Λ$ interactions are introduced %in the same covariant framework. We found that the density profiles of SD states in Ar isotopes show a strong localization with a ring structure near the surface, while the central part of the density is dilute showing a hole structure. This localization of SD density induces an appreciable deformation in …
We present the first ab initio calculations for p-shell single-Lambda hypernuclei. For the solution of the many-baryon problem, we develop two variants of the no-core shell model with explicit $Λ$ and $Σ^+$, $Σ^0$, $Σ^-$ hyperons including $Λ$-$Σ$ conversion, optionally supplemented by a similarity renormalization group transformation to accelerate model-space convergence. In addition to state-of-the-art chiral two- and three-nucleon interactions, we use leading-order chiral hyperon-nucleon interactions and a recent meson-exchange hyperon-nucleon interaction. We validate the approach for s-she…
The impurity effect of hyperon on atomic nuclei has received a renewed interest in nuclear physics since the first experimental observation of appreciable reduction of $E2$ transition strength in low-lying states of hypernucleus $^{7}_Λ$Li. Many more data on low-lying states of $Λ$ hypernuclei will be measured soon for $sd$-shell nuclei, providing good opportunities to study the $Λ$ impurity effect on nuclear low-energy excitations. We carry out a quantitative analysis of $Λ$ hyperon impurity effect on the low-lying states of $sd$-shell nuclei at the beyond-mean-field level based on a relativi…
An accurate assessment of the hyperon-nucleon interaction is of great interest in view of recent observations of very massive neutron stars. The challenge is to build a realistic interaction that can be used over a wide range of masses and in infinite matter starting from the available experimental data on the binding energy of light hypernuclei. To this end, accurate calculations of the hyperon binding energy in a hypernucleus are necessary. We present a quantum Monte Carlo study of $Λ$ and $ΛΛ$ hypernuclei up to $A=91$. We investigate the contribution of two- and three-body $Λ$-nucleon force…
An error in the computer program which evaluated nucleon spectra following the decay of $Λ$ hypernuclei has been detected. The error affected the final state interaction (FSI) of the nucleons, reducing by a factor ten the nucleon-nucleon (NN) collision probability. When correcting the error, some results and conclusions of Ref. [1] have changed substantially.
The shapes of light normal nuclei and $Λ$ hypernuclei are investigated in the $(β, γ)$ deformation plane by using a newly developed constrained relativistic mean field (RMF) model. As examples, the results of some C, Mg, and Si nuclei are presented and discussed in details. We found that for normal nuclei the present RMF calculations and previous Skyrme-Hartree-Fock models predict similar trends of the shape evolution with the neutron number increasing. But some quantitative aspects from these two approaches, such as the depth of the minimum and the softness in the $γ$ direction, differ a lot …
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…
We develop both relativistic mean field and beyond approaches for hypernuclei with possible quadrupole-octupole deformation or pear-like shapes based on relativistic point-coupling energy density functionals. The symmetries broken in the mean-field states are recovered with parity, particle-number, and angular momentum projections. We take $^{21}_Λ$Ne as an example to illustrate the method, where the $Λ$ hyperon is put on one of the two lowest-energy orbits (labeled as $Λ_s, Λ_p$), respectively. We find that the $Λ$ hyperon in both cases disfavors the formation of a reflection-asymmetric molec…
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.
Based on relativistic mean field (RMF) models, we study finite $Λ$-hypernuclei and massive neutron stars. The effective $N$-$N$ interactions PK1 and TM1 are adopted, while the $N$-$Λ$ interactions are constrained by reproducing the binding energy of $Λ$-hyperon at $1s$ orbit of $^{40}_Λ$Ca. It is found that the $Λ$-meson couplings follow a simple relation, indicating a fixed $Λ$ potential well for symmetric nuclear matter at saturation densities, i.e., around $V_Λ = -29.786$ MeV. With those interactions, a large mass range of $Λ$-hypernuclei can be well described. Furthermore, the masses of PS…
