利用手征SU(3)夸克模型研究轻双Λ超核^6_ΛΛHe,^5_ΛΛHe,^5_ΛΛH,^4_ΛΛHe,和^4_ΛΛH的结合能

在手征SU(3)夸克集团模型下, 通过共振群方法(RGM)计算了双Λ超核^6_ΛΛHe,^5_ΛΛHe,^5_ΛΛH,^4_ΛΛHe,和^4_ΛΛH的结合能. 结果表明, 假定双Λ超核具有双Λ集团和壳心核集团构成的两集团结构, 得到的^6_ΛΛHe超核的结合能与实验值基本吻合, 表明手征SU(3)夸克集团模型不仅能较好地描述重子谱、N-N和Y-N相互作用及轻Λ超核的结合能, 也能较好地描述Y-Y相互作用及双Λ超核^6_ΛΛHe,^5_ΛΛHe,^5_ΛΛH,^4_ΛΛHe,和^4_ΛΛH的结合能, 指出了它们存在的可能性.     

Λ4He和Λ4H的Λ分离能及能谱

本文利用我们以前所得的Λ-N交换势,计算了_Λ⁴He和_Λ⁴H的Λ分离能及其能谱。为简单起见,我们假定单粒子的径向部分取为⁴He的电荷形状因子。计算结果与实验值符合得较好。     

利用手征SU(3)夸克模型研究轻双Λ超核_(ΛΛ)~6He,_(ΛΛ)~5He, _(ΛΛ)~5H,_(ΛΛ) ~4He和_(ΛΛ)~4H的结合能

在手征SU(3)夸克集团模型下,通过共振群方法(RGM)计算了双Λ超核~6_(ΛΛ)He, ~5_(ΛΛ)He, ~5_(ΛΛ)H, ~4_(ΛΛ)He和~4_(ΛΛ)H的结合能．结果表明,假定双Λ超核具有双Λ集团和壳心核集团构成的两集团结构,得到的~6_(ΛΛ)He超核的结合能与实验值基本吻合,表明手征SU(3)夸克集团模型不仅能较好地描述重子谱、N-N和Y-N相互作用及轻Λ超核的结合能,也能较好地描述Y-Y相互作用及双Λ超核的结合能．使用相同的模型参数,计算了轻双Λ超核~5_(ΛΛ)He, ~5_(ΛΛ)H, ~4_(ΛΛ)He和~4_(ΛΛ)H的结合能,指出了它们存在的可能性．     

粲Λ-核子相互作用和粲Λ核结合能

本文用Hartree-Fock方法计算了Λ超核⁵_ΛHe与⁹_ΛBe的Λ的结合能及粲Λ(Λ_c)核⁵_ΛHe与⁹_ΛBe的Λ_c的结合能. 在使前两者的Λ结合能之比与后两者的Λ_c结合能之比相等时, 定出Λ_c与核子的相互作用约为Λ与核子的相互作用的4/5. 用此相互作用计算了1p壳Λ超核和Λ_c核的结合能, 结果表明核芯A≥4的Λ_c核是存在的.     

双重子共振态的么正对称性

本文提出双重子共振态pp、pn、Λp、Σ^－p、ΛΛ和Ξ^－p等填充SU(3)群27维表示的可能性. 理论与实验符合得很好. 指出了可能存在的其它双重子共振态及其性质.     

极化电子与极化核子的深度非弹散射过程

本文在光锥代数的基础上,用层子模型中核子的波函数和计算方法,由vW₂^P的实验曲线定出参数,并计算了 vG₁、v²G₂的值,得到了具有一定自旋取向的价层子的分布函数 h（?）（x）.其中波函数中的时空函数取类谐振子的形式.文中对具有 SU（6）对称和不具有 SU（6）对称的两种旋量结构进行了讨论.计算得到的 A₁^P×vW₂^P 的理论值与实验相符合,对 SU（6）对称情况得到6 integral from 0 to 1{vG₁^P-vG₁ⁿ}dx=-1.16,实验支持 SU（6）对称的波函数.     

Excess 3H in the volcanic lakes: evidence for natural nuclear fusion

The excess ³H (tritium) have been observed in the volcanic lakes Nemrut (Turkey), Laacher (Germany) and Pavin (France). The ⁴He and ³He concentrations in Lakes Nemrut, Laacher, and Pavin were determined to be 25 and 190, 10 and 50, and 70 and 500 times larger than the atmospheric saturation value respectively. The isotopic ratio of the helium excess, ³He_ex/⁴He_ex, in Lakes Nemrut, Laacher and Pavin was (1.032±0.006)×10^－5, (7.42±0.03)×10^－6 and (9.09±0.01)×10^－6 respectively. The ³He/⁴He ratio of helium isotopes in the lake can help us to identify the origin of gas fluxes from the interior of the Earth. The ³He/⁴He ratios in the Lakes Nemrut, Laacher and Pavin clearly indicate that a large amount of helium isotopes were released to the lakes from mantle source. The excess ³H at the bottom of Lakes Nemrut, Laacher and Pavin have a good correlation with mantle ³He. We consider that the excess ³H might be also released from mantle source and both ³H and ³He might be produced by nuclear fusion (d-d reaction) in an environment rich in H atoms and (U+Th) at high temperature and high pressure condition in deep Earth.     

双超核ΛΛ5H,ΛΛ5He,ΛΛ4H,ΛΛ4He的研究

用少体理论方法对双Λ超核ΛΛ5He(ΛΛ5H)及ΛΛ4He(ΛΛ4H)的结合能进行了计算．结果表明,ΛΛ5He(ΛΛ5H)存在稳定的束缚态. 它们的双Λ结合能分别为对的研究的初步结果表明，它存在束缚态但相对于衰变不稳定．至于，结论是它不存在束缚态．     

Constraint on the warped space from B→X_sγ

We analyze the theoretical prediction on the branching ratio of B→X_sγ to order Λ_EW²/Λ_KK² in extension of the standard model with a warped extra dimension and the custodial symmetry SU(3)_c×SU(2)_L×SU(2)_R×U(1)_X×P_LR, where Λ_KK denotes the energy scale of low-lying Kaluze-Klein excitations and Λ_EW denotes the electroweak energy scale. Contributions from the in nite series of Kaluze-Klein excitations are summed over through the residue theorem. The numerical result indicates that the present experimental data constrain the parameter space of the concerned model strongly.     

关于Λ-α有效相互作用以及超核6He与9Be的研究

本文用给出⁵He的Λ结合能实验值的Λ-α有效相互作用, 统一地用超球谐函数方法的绝热近似, 研究了超核⁶He的双Λ结合能与⁹Be的Λ结合能. 得到的结果比较满意的.     

Hypertriton and light nuclei production at Λ-production subthreshold energy in heavy-ion collisions

High-energy heavy-ion collisions produce abundant hyperons and nucleons. A dynamical coalescence model coupled with the ART model is employed to study the production probabilities of light clusters, deuteron (d), triton (t), helion (³He), and hypertriton (_Λ³H) at subthreshold energy of Λ production (≈ 1 GeV per nucleon). We study the dependence on the reaction system size of the coalescence penalty factor per additional nucleon and entropy per nucleon. The Strangeness Population Factor (S₃ / (³He × (Λ/p))) shows an extra suppression of hypertriton comparing to light clusters of the same mass number. This model predicts a hypertriton production cross-section of a few μb in ³⁶Ar+³⁶Ar, ⁴⁰Ca+⁴⁰Ca and ⁵⁶Ni+⁵⁶Ni in 1 A GeV reactions. The production rate is as high as a few hypertritons per million collisions, which shows that the fixed-target heavy-ion collisions at CSR (Lanzhou/China) at Λ subthreshold energy are suitable for breaking new ground in hypernuclear physics.     

π-核散射△33准门口态模型的分析

本文在π-核散射的Δ₃₃准门口态模型下,计算了不同入射能量的π-⁴He(T_π^1ab=110、150、180、220、260MeV)和π-⁴⁰Ca(T_π^1ab=115.5、163.3、241.0MeV)弹性散射的微分截面和总截面,结果与实验大致符合。对于π-⁴He散射,我们进一步考虑了自旋轨道耦合效应的修正,得到了与实验更好的符合。     

U(6/20)超对称性的SU(3)的极限

本文讨论U(6/20)超对称性的SU(3)极限. 首先讨论有关群链的诸环节的约化问题, 接着讨论动力学的对称性, 而后以²³⁵₉₂U₁₄₃核将理论和实验作一比较.     

Properties of Zr hypernuclei in deformed Skyrme Hartree-Fock approach

Properties of the even-N Zr isotopes and their corresponding single-Λ and double-Λ hypernuclei are studied in the deformed Skyrme-Hartree-Fock approach. Binding energy, the two-neutron separation energies, radii are studied from beta-stable zone to the neutron drip line in this paper. The neutron drip line nuclei predicted with SLy4 and SkI4 interactions are ¹²²Zr and ¹³⁸Zr, respectively. The neutron drip line of single-Λ and double-Λ hypernuclei are ¹³⁹_ΛZr and ¹⁴²_2ΛZr with SkI4 interaction, respectively. The predicted hyperon drip line hypernuclei with ⁸⁰Zr and ¹³⁸Zr cores are ¹⁰⁰_20ΛZr and ¹⁸⁸_50ΛZr, respectively.     

对A=3的Λ超核的讨论

本文利用我们以前所得到的A-N交换势,计算了_A³He和_A³H基态结合能之差,此外还计算了_A³H的两个低激发态的激发能。我们的计算结果与实验相比较还是合理的。     

(p,π)反应的微观描述

本文推广了W. Weise等人处理π核散射的方法,把它用于研究（p,π）反应,并用此方法计算了³He（P,π⁺）⁴He(T_p^1ab=415MeV)的角分布。所得角分布的形状与实验符合,绝对值比实验值大3-5倍。     

Angular distribution of ~6He+p elastic scattering

The angular distribution of ¹H(⁶He,p)⁶He elastic scattering has been measured at E_c.m.=4.3 MeV by using a thick-target inverse kinematic method. The experimental differential cross sections are reproduced by the distorted-wave Born approximation calculation utilizing the CH89 global optical potential parameter set. The real part of CH89 is reduced comparing with other potentials, which may be attributed to the couplings necessary for the weakly bound nuclei.     

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.     

Evidence for further charmonium vector resonances

We discuss the shape of threshold signals in production cross sections of the reaction e⁺e^-→ D^*D^*, at the opening of the D_s^*D_s^* and Λ_c⁺Λ_c^- channels. Furthermore, evidence for the ψ(3D), ψ(5S), ψ(4D), ψ(6S), ψ(5D), ψ(7S), ψ(6D), and ψ(8S) new charmonium vector resonances is presented, on the basis of data recently published by the BABAR Collaboration. Central masses and resonance widths are estimated. Confirmation of these resonances would be a huge step in lifting the precision level of hadron spectroscopy towards that of atomic spectroscopy, with far-reaching consequences for theory.     

Deeply bound kaonic states in nuclei

Using a new phenomenological KN interaction which reproduces Λ(1405) as an I=0 bound state of KN, we have investigated K^－－³ He(T=0) and K^－－⁴ He(T=1/2) within the framework of the Brueckner-Hartree-Fock(BHF) theory. Our calculations show that the above kaonic nuclear systems are both deeply bound. The binding energy B_K－ is 124.4 MeV(94.1 MeV) and the width Γ is 11.8 MeV(25.8 MeV) for K^－－³He(T=0) (K^－－⁴He(T=1/2)).