PATH INTEGRAL IN CORRELATED EIGENSTATE BASIS OF COMPLEX SCALAR FIELDS φ(x) AND φ?(x)

Using the technique of integration within an ordered product of operators, we construct a new common eigenvector set of the complex scalar fields φ(x) and φ^?(x), which is a set of particle-antiparticle correlated states. On the basis of the new eigenstates we develop the path integral formuation. The new eigenvectors' properties are investigated, they are qualified to be a new representation.     

B ?→ K 1*? (1270)(→ ρ 0 K ?) ? + ? ? in LEET

Flavor changing neutral current (FCNC) decays of the B-meson are a very useful tool for studying possible physics scenarios beyond the standard model (SM), where of the many FCNC modes radiative, purely leptonic and semi-leptonic decays of the B-meson are relatively clean tests. Within this context, the BELLE collaboration has measured the process B→K ^* γ and also searched for the B→K ₁(1270)γ process. Theoretical analyses of these processes are yielding similar values of the relevant form factors. In this work we have used this upper bound in studying the angular correlations for the related semi-leptonic decay mode B ⁻→K ₁⁻(1270)(→ρ ⁰ K ⁻)ℓ ⁺ ℓ ⁻, where we have used the form factors that have already been estimated for the B→K ₁(1270)γ mode. Note that the additional form factors that are required were calculated using large energy effective theory (LEET).     

ρ0 production the reaction ξξ→3π+3π?ξξ→ρ0ρ0(1700)

We have studied the ⁰ production rate in the reaction 3⁺3^– in the energy range 1.6W 7.5 GeV with the CELLO detector at PETRA. Our analysis points to a substantial yield of ^00+– events in particular atW >4.0 GeV. We give cross sections for the ⁰2⁺2^– and ^00+– final states and calculate upper limits for the reaction ⁰⁰ (1700) ^00+–.Now at CERN     

20 Ne(34 Ne)原子与18 Na2(23 Na2,37 Na2)分子低温下冷碰撞的同位素效应研究

本文用多体刚性椭球模型计算了相对入射能量为190 meV时,氖的同位素原子²⁰Ne,³⁴Ne与钠的同位素分子¹⁸Na₂,²³Na₂,³⁷Na₂ 替代碰撞体系的态态转动激发积分散射截面和总转动激发积分散射截面,在此基础上计算并分析了相互作用势的不同区域对²⁰Ne-¹⁸Na_{2关键词： 多体刚性椭球模型 转动激发积分散射截面 钠同位素分子 椭球等势面}     

Reaction e + e ? → π + π ? π + π ? at energies of √ s ≤ 1 GeV

The e ⁺ e ⁻ → π ⁺ π ⁻ π ⁺ π ⁻ cross section is calculated for energies of 0.65 ≤ √s ≤ 1 GeV in the framework of the generalized hidden local symmetry model. The calculations are compared with the data of CMD-2 and BaBaR. It is shown that the inclusion of heavy isovector resonances ρ(1450) and ρ(1700) is necessary for reconciling calculations with the data. It is found that, at √s ≈ 1 GeV, the contributions of the above resonances are much larger, by a factor of 30, than the ρ(770) one, and amount to a considerable fraction ∼0.3–0.6 of the latter at √s ∼ m _ρ. The text was submitted by the authors in English.     

J/ψ→π03(π+π－)分支比的测定

用BESⅠ的7.8×10⁶J/ψ数据更为精确地测定了J/ψ→π⁰3(π⁺π^－)和J/ψ→ω²(π⁺π^－)的分支比(Br(J/ψ→π⁰3(π⁺π^－))=(2.52±0.06±0.43)%,Br(J/ψ→π⁰3(π⁺π^－))=(1.31±0.09±0.21)%.同时对4π不变质量谱和ωππ不变质量谱进行研究分析,试图观察是否存在有兴趣的信号.     

OPTICAL-OPTICAL DOUBLE-RESONANCE EXCITATION SPECTRA OF THE (6d)1Πg, (7d)1Πg HIGH-LYING RYDBERG STATES IN Na2

Two ¹Π_g states of Na₂ for v≤13 have been observed by using optical-optical double resonance (OODR) fluorescence excitation spectroscopy. The intermediate levels in B¹Π_u state are identified by the numerical calculations with the molec-ular constants for B¹Π_u←X¹Σ_g⁺ transitions and confirmed by the complemen-tary A¹Σ_g⁺←X¹Σ_g⁺ polarization spectra. Absolute vibrational numberings of the (6d)¹Π_g and (7d)¹Π_g states are determined by comparing the experimental OODR excitation intensities with the simulated Franck-Condon factors. The Dnnham coef-ficients and the Rydberg-Klein-Rees (RKR) potential energy curves of the (6d)¹Π_g, (7d)¹Π_g states are reported.     

Lifetime vibrational interference during the NO 1s-1π* resonant excitation studied by the NO+(A 1Π → X 1Σ+) fluorescence

Dispersed fluorescence from fragments formed after the de-excitation of the 1s^-1π^* resonances of N^*O and NO^* has been measured in the spectral range of 118–142 nm. This range is dominated by lines of atomic nitrogen and oxygen fragments and by the bands in the NO⁺ ion which result from the participator Auger decay of the 1s^-1π^* resonances. Ab-initio calculations of the transition probabilities between vibrational levels during the reaction NO N^*O ⇒ NO were used to explain the observed intensity dependence for the fluorescence bands on the exciting-photon energy across the resonances and on both v^′ and v^′′ vibrational quantum numbers. The multiplet structure of the 1s^-1π^* resonance and lifetime vibrational interference explain the observed exciting-photon energy dependence of the fluorescence intensity. A strong spin-orbit coupling between singlet and triplet states of NO⁺ is proposed to reduce additional cascade population of the state via radiative transitions from the and states and to explain remaining differences between measured and calculated integral fluorescence intensities.     

THE TWO-BOSON SCATTERING PHASE SHIFTS IN THE GENERAL φ6 THEORY WITH THE GAUSSIAN WAVE-FUNCTIONAL APPROACH

The two-particle scattering phase shifts with a λφ⁴ +ξφ⁶ interaction are com-puted in (1 + 1) and (2 + 1) dimensions using the Gaussian wave-functional approach.Through numerical analysis, we give the phase-shift curves with respect to the scat-tering energy for most cases of this theory. In (1 + 1) and (2 + 1 ) dimensions, for the symmetry vacuum the phase shifts are positive or negative depending on the signs of the renormalized parameter, while for the asymmetric vacuum the phase shifts are negative.     

基于从头算势能面对S-(2P)+H2(1Σ+g)→SH-(1Σ)+H(2S)反应的量子含时波包计算

本文基于离子分子SH₂^-基态势能面,应用含时波包方法研究了反应S^-(²P)+H₂(¹Σ⁺_g)→SH^-(¹Σ)+H(²S)的动力学行为. 给出了反应几率和积分截面随碰撞能的变化关系,结果表明,在讨论的所有碰撞能量范围内二者均存在显著的振荡结构. 当初始转动量子数j=0,2,4,6,8,10和振动量子数v=0,1,2,3,4时,从总反应几率数值计算中可以看出,双原子H₂的振动激发和转动激发显著提高了反应活性. 同时积分散射截面的理论值与前人的实验值相符合.     

Ba(n,x)134Cs,134Ba(n,2n)133Ba,140Ce(n,2n)139Ce,142Ce(n,2n)141)Ce和23Na(n,2n)22Na反应截面的测量

用中子活化法相对于⁵⁴Fe(n,P)⁵⁴Mn反应,在13.50—14.80MeV中子能区测量了Ba(n,x)¹³⁴Cs,¹³⁴Ba(n,2n)¹³³Ba,¹⁴⁰Ce(n,2n)¹³⁹Ce,¹⁴²Ce(n,2n)¹⁴¹Ce和²³Na(n,2n)²²Na的反应截面.并将所测的结果和其他作者的结果进行了比较,中子能量是用⁹⁰Zr(n,2n)^89m+gZr反应和⁹³Nb(n,2n)^92mNb反应截面比法测定的.     

缺中子核素129Ce的(EC/β+)衰变

利用102MeV¹⁶O⁶⁺束轰击同位素靶¹¹⁷Sn,通过熔合蒸发4n反应产生核素¹²⁹Ce.由氦喷嘴快速带传输系统将反应产物送到低本底区.通过化学分离来制备待测的Ce样品,与此同时用¹⁶O束轰击¹¹⁷Sn的两种相邻的同位素靶¹¹⁸Sn和¹¹⁶Sn,并比较上述3种反应中的产物来进一步区分元素Ce的不同的同位素.结果一种半衰期为4.1min的活性被鉴定为¹²⁹Ce.基于X–γ–t和γ–γ–t符合测量,建议了包括51条射线在内的¹²⁹Ce的(EC/β⁺)衰变纲图.其中,¹²⁹Ce基态直接馈送到¹²⁹La基态的份额(26±7)%是用观测到的¹²⁹La衰变的278.6keV的γ射线的生长和衰变曲线估计出来的.另外还给出了用La-K_α-X射线和68.2keVγ射线开门的γ谱以及典型的衰变γ射线的时间谱.     

关于介分子离子(αp,μ－)和(αp,2μ－)

应用ACQM理论和方法研究介分子离子(αp,μ^－)和(αp,2μ^－).发现(αp,μ^－)的基态(X²Σ⁺)为排斥态;(αp,2μ^－)为束缚态,平衡核间距R_e=0.0078bohr,能量极小值E=－551.78a.u..     

Mg-CO(X1Σ+)体系的冷碰撞动力学

应用量子散射动力学方法, 研究了电场条件下Mg-CO体系的冷碰撞动力学性质, 探索了外电场对碰撞体系低场追索态的弹性和非弹性截面的影响, 为碱土金属Mg原子感应冷却CO分子提供理论预测.     

τ±→π±+nπ0+ντ(n=0,1,2)衰变分支比测量

基于北京谱仪收集的4.03GeV质心系能量下e⁺e^－对撞数据,分析τ^±τ^±→e^±+π^±+nπ⁰+ν's(n=0,1,2)事例,给出分支比值Br(τ^±→π^±ν_τ)=(11.64±0.49^+0.76_－0.73%,Br(τ^±→π^±π⁰ν_τ)=(24.00±1.34^+1.36_－1.30%,Br(τ^±→π^±2π⁰ν_τ)=(9.39±1.68^+1.69_－1.66%.     

14MeV中子引起的Pb(n,x)203Hg, W(n,x)182Ta和W(n,x)183Ta的核反应截面测量

利用活化方法测量了14MeV中子引起的Pb(n,x)²⁰³Hg,W(n,x)¹⁸²Ta和W(n,x)¹⁸³Ta的反应截面.中子注量由监督反应⁹³Nb(n,2n)^92mNb给出,中子能量利用⁹⁰Zr(n,2n)^89m+gZr和⁹³Nb(n,2n)^92mNb反应的截面比来确定.     

160Gd(n,2n)159Gd和158Gd(n,p)158Eu反应截面测量

报道了在13.5—14.6MeV中子能区用活化法测得的¹⁶⁰Gd(n,2n)¹⁵⁹Gd和¹⁵⁸Gd(n,p)¹⁵⁸Eu的 反应截面值. 中子注量用⁹³Nb(n, 2n)⁹²m Nb反应截面得到. 由(13.5±0.2)MeV,(14.1±0.1)MeV和(14.6±0.2)MeV中子引起的¹⁶⁰Gd(n, 2n) ¹⁵⁹Gd反应截面值分别为(1940±83)mb, (2324±92)mb和(1983±77)mb, ¹⁵⁸Gd(n, p) ¹⁵⁸Eu反应截面值分别为(1.9±0.1)mb, (2.1±0.1)mb和(3.5±0.1)mb. 单能中子由T(d, n)⁴He反应获得.文中还列举了已收集到的数据以作比较.     

由宇宙线(1011—1014电子伏)引起的高能核作用

这篇总结性文章叙论了由能量高到10¹¹—10¹⁴电子伏的粒子在乳胶和云室中所引起的高能核作用。文中首先提出和讨论了在测量上较困难的一些问题,例如,初能量的测量,次粒子的辨认和靶质量的估计。一些可能揭示碰撞机构从而显示核子内部结构的物理量的物理意义,也适当地加以讨论和阐明。除了不同次粒子的多重性外,主要的物理量是:次粒子的角分布、它们的横动量和非弹性系数。关于这些量的测量原理,实验准确度和实验结果的物理意义,特别是后面一点,都有了较充分的检查和讨论。末了,“一个发射中心”和两个发射中心”的各种模型也从物理观点作了较定性的描述和讨论,并和实验结果作了比较。希望通过这篇文章对高能核作用目前发展的概况、尚存在的问题及今后工作的方向能有一定的了解。     

铅区核的结构(Ⅱ)208)Tl、208Pb和206—208)Hg的一级禁戒β衰变

用壳模型对²⁰⁸Tl、²⁰⁸Pb和^206—208)Hg的非唯一型一级禁戒β跃迁用不同的有效相互作用和模型空间进行了系统计算,计算的比较寿命Iogf非常敏感的依赖于有效相互作用. 对^206,208Hg的β衰变方式进行了比较.