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。     

Investigation of Hypernucleus Λ5He Structure and the Calculation of the Binding Energy

In this paper the nuclear structure of hypernucleus ₅^ΛHe and its effect on the binding energy B_Λ of A hyperon are systematically studied. The Polarization effect of the core a is explored. The binding energy B_Λ of ₅^ΛHe including D-state mixing component is calculated. The results show that the core α suffers a serious distortion by the interaction with Λ hyperon and has no longer the structure of a free Alpha Particle. The D-state mixing can improve the B_Λ calculated value about 0.5MeV. A Possible three cluster structure is further explored. The Λ+d+d model can give a B_Λ value close to the experimental one. The further exploration is necessary.     

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．     

100—300MeV3He(π－,n)2H反应的微观描述

本文将G.E.Brown等研究π^－核散射的Isobar模型推广应用到中能(π,N)反应的描述上,用唯象近似方法处理多体效应, 探讨了非表态修正、核子关联波函数以及出射核子扭曲效应对反应微分截面的影响, 计算了100—300MeV³He(π^－,n)²H反应角分布, 所得结果与实验基本一致.     

Medium Effects and Thermal Instability in φ63 Theory

We calculate the effective mass and damping rate in φ₆³ theory at finite temperature by evaluating the real and imaginary parts of the one-loop self energies at the hard thermal loop (HTL) approximation. We show that there is thermal instability above a critical temperature Tc. The effective mass and damping rate are proportional to gT and gT respectively. We compare our results with those in hot QCD.     

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.     

π-4He吸收后的核子谱

在两核子吸收的框架下, 我们分析了静止的π^－以及60、100和220MeV的π^±介子在⁴He上吸收后发射的核子谱. 两核子吸收机制定量地符合现有实验. 四核子的相空间计算与实验不符.     

多模叠加态光场|ψ5(3)〉q中广义磁场4m次方Y压缩

构造了由多模复共轭相干态|{Z_j^*}〉_q、多模复共轭相干态的相反态|{-Z_j^*}〉_q以及多模虚相干态|{iZ_j^*}〉_q的线性叠加所组成的第Ⅴ类三态叠加多模叠加态光场|ψ₅⁽³⁾〉_q.利用多模压缩态理论研究了态|ψ₅⁽³⁾〉_q中广义磁场分量的等幂次N次方Y压缩特性.结果发现:当压缩次数N=2p且p=2m(m=1,2,3,…,…)时,只要各模的初始相位φ_j(j=1,2,…,…,q)、态间的初始相位差(θ₁-θ₂)、(θ₁-θ₃)和(θ₂-θ₃)以及受各模的初始相位φ_j调制的各单模相干态光场的平均光子数之和 等分别满足一定的取值条件,则态|ψ₅⁽³⁾〉_q的广义磁场分量就可呈现出周期性变化的广义非线性等幂次4m次方Y压缩效应.     

Study of Ds±→μ±νμ at Belle

We present a preliminary measurement of the B(D_s→μν_μ) with the Belle
experiment at the KEKB collider. We select D_s→μν_μ decays with a method that provides a high-purity of the selected sample and an absolute measurement of the branching fraction. The results are based on a data sample of 550fb^－1 and are compared to similar measurements by other experiments as well as to the predictions of LQCD. We conclude with short prospects for improvements in the accuracy of the measurement.

     

Study of Ds±→μ±νμ at Belle

We present a preliminary measurement of the B(D_s→μν_μ) with the Belle     

Study about the Binding Energy of Light Double Hypernuclei ^6_ΛΛHe,^5_ΛΛHe,^5_ΛΛH,^4_ΛΛHe,and ^4_ΛΛH Based on Chiral SU(3) Quark Model

In the framework of the resonating group method, the binding energies of double lambda hypernuclei ^6_ΛΛHe,^5_ΛΛHe,^5_ΛΛH,^4_ΛΛHe,and ^4_ΛΛH are calculated in the chiral SU(3) quark model. In the two-cluster approximation in which a two-lambda cluster and a core nuclei are considered, one finds that the resultant binding energy of double-lambda hypernuclei ^6_ΛΛHe is in good agreement with the experimental data. It means that the chiral SU(3) quark model can well-describe the spectrum of baryon, the interactions of N-N, Y-N, and the binding energies of light lambda hpernuclei, as well as the interaction of Y-Y and the binding energy of double-lambda hypernucleus. With the same set of parameters, we calculate the binding energies of light double-lambda hypernuclei ^6_ΛΛHe,^5_ΛΛHe,^5_ΛΛH,^4_ΛΛHe,and ^4_ΛΛH and discuss the possibilities of these states.     

高能质子在4He上的弹性散射和极化

本文用包含核子自旋效应的 Glauber 理论,计算能区在0.35—23.1 GeV 间的 p-⁴He 弹性散射和极化角分布,结果表明,加上自旋效应之后,能解释微分截面的实验结果和定性的符合极化角分布.     

Fore-aft asymmetry of the 2H(n,γ)3H at very low energies

We have used the recent effective field theory (EFT) which is constructed from two-and three-nucleon interactions, using minimal substitution in the momentum dependence of these interactions. We present the calculations of the fore-aft asymmetry of γ-rays in the reaction ²H(n,γ)³H which are based on EFT up to next-to-next-to leading order (N²LO). The results are compared with the recently reported calculations and measurements of the fore-aft asymmetry of γ-rays from neutron-deuteron radiative capture. The calculated fore-aft asymmetry of the nd radiative capture process above deuteron breakup threshold is in good agreement with the available experimental data up to 20 MeV.     

双超核_（ΛΛ）~5H，_（ΛΛ）~5He，_（ΛΛ）~4H，_（ΛΛ）~4He的研究

用少体理论方法对双超核及的结合能进行了计算．结果表明，存在稳定的束缚态．它们的双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．     

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．     

Nd∶KY(WO4)2和Nd∶KG(WO4)2晶体吸收光谱性能分析

通过研究分析钨酸盐晶体Nd∶KY(WO₄)₂和Nd∶KG(WO₄)₂在室温下的吸收光谱，发现这2种晶体具有作为激光晶体的优良特性。根据Judd-Ofelt理论和测试所得的吸收光谱及数据，用VC++编程计算出晶体的谱线强度、振子强度、吸收截面等，拟合得Nd³⁺离子的3个晶场调节参数Ω_λ(λ=2，4，6)的值，并从理论上计算了自发跃迁几率、能级寿命、荧光分支比和积分发射截面。从计算得出的荧光分支比β可以看出，Nd∶KY(WO₄)₂(β_1060nm=0.4380)和Nd∶KG(WO₄)₂(β_1060nm=0.4618)晶体荧光分支比都较大，计算了该晶体的X=Ω₄/Ω₆，并将其X值与其他晶体的X值加以比较，Nd∶KY(WO₄)₂和Nd∶KG(WO₄)₂均易于实现1.06μm激光输出，适合作为LD泵浦的钨酸盐晶体激光器。     

ΛΛ,ΛΛγ and ΛΛπ0 Productions in J/ψ Decay

The channels of J/ψ decay into,ΛΛ,ΛΛγ and ΛΛπ⁰ are analyzed with 7.8×10⁶ J/ψ events collected by BES detector at BEPC Collider.The branching ratios for three channels and the angular distribution for the first channel are measured.The branching ratios are Br(J/ψ→ΛΛ)=(l.08±0.06±0.24)×10^－3,Br(J/ψ→ΛΛγ)－4(90% CL)and Br(J/ψ→ΛΛπ⁰)=(2.3±0.7±0.8)×l0^－4 respectively. The angular distribution for J/ψ→ΛΛ is dN dcosθ=N₀(1+αcos²0),α=0.52±0.33±0.13.     

J/ψ衰变中的ΛΛ,ΛΛγ和ΛΛπ0产生

利用北京正负电子对撞机(BEPC)上的北京谱仪(BES)收集的7.8×10⁶个J/ψ事例,测量得到J/ψ→ΛΛ,ΛΛγ和ΛΛπ⁰三个衰变道的分支比分别为Br(J/ψ→ΛΛ)=(l.08±0.06±0.24)×10^－3,Br(J/ψ→ΛΛγ)－4(90% CL),和Br(J/ψ→ΛΛπ⁰)=(2.3±0.7±0.8)×l0^－4; 第一个衰变道的角分布为dN dcosθ=N₀(1+αcos²0),α=0.52±0.33±0.13.     

Photoinduced Resistance Change in an Oxygen-Deficient La 0.9 Sr 0.1 MnO 3-δ Thin Film

Photoinduced resistance change （ △ R/R） in an oxygen-deficient La0.9Sr0.1MnO3-δ thin film is studied. At room temperature, the resistance change of about 30% and response time of about 75 ns are observed under the illumination with a 532nm laser pulse of 7ns and light power of 750mW. It is also found that △ R/R changes with the light power. The phenomena are explained in terms of the photoinduced hole carriers and localized insulator-to-metal transition, which may have potential applications in optoelectronic devices.