Charmless Hadronic Decays B→VV in the Topcolor-Assisted Technicolor Model

Based. On the effective Hamiltonian with the generalized factorization approach, we calculate the branchingratios and CP asymmetries of B → VV decays in the Topcolor-assisted Technicolor (TC2) model. Within the consideredparameter space we find that: (a) for the penguin-dominated B → K* φ and K*0 φ decays, the new physics enhancementsto the branching ratios are around 40%; (b) the measured branching ratios of B →K* φ and K*0φ decays prefer therange of 3 Neffc 5; (c) the SM and TC2 model predictions for the branching ratio B(B →ρ ρ0) are only about halfof the Belle‘s measurement; and (d) for most B → VV decays, the new physics corrections on their CP asymmetries are generally small or moderate in magnitude and insensitive to the variation of mπ and Neffc.     

Constraints on Technicolor Models from Inclusive Decay of B Meson

Corrections to the branching ratio BR (B → X_s γ) from technipions and top pions appeared in technicolor models are investigated. We found that: (a) the multiscale walking technicolor model is ruled out since it is conflict with the CLEO data; (b) the topcolor-assisted technicolor model is consistent with the CLEO data of BR(B → X_s γ) for a certain range of parameters.     

用微扰QCD方法研究B(s)→Φρ衰变

用微扰QCD对B(s)→Φρ衰变进行了研究,考虑了因子化和非因子化图的贡献,得出了B(s)→Φρ衰变的分支比以及纵向极化衰变、横向极化衰变之比,所得到的结果与现在的实验数据吻合.     

B→KK衰变中的软胶子修正

应用光维QCD求和规则研究了B→KK衰变的软胶子交换修正,虽然QCD因子化方法已经计算了领头阶的因子化和硬胶子交换的α_s阶辐射修正部分,然而系统地估算所有树图和企鹅图的非因子化软胶子贡献是有价值的,我们的结果表明在B→KK衰变中软胶子效应总是使分支比值减小,约为几个百分点.     

B→K_0~*(1430)η~(') decays in the pQCD approach

Based on the assumption of two-quark structure of the scalar meson K*0(1430),we calculate the CP-averaged branching ratios for B→K0*(1430)η(') decays in the framework of the perturbative QCD(pQCD) approach here.We perform the evaluations in two scenarios for the scalar meson spectrum.We find that:(a) the pQCD predictions for Br(B→K*0(1430)η(')) which are about 10-5-10-6,basically agree with the data within large theoretical uncertainty;(b) the agreement between the pQCD predictions and the data in Scenario I is better than that in Scenario II,which can be tested by the forthcoming LHC experiments;(c) the annihilation contributions play an important role for these considered decays.     

核子共振态的螺旋度振幅的计算

相对论夸克模型用来计算面和N^*的电产生振幅.介子云的贡献是一个重要的课题.计算表明考虑了介子云的作用对Δ和N^*(1440)螺旋度振幅的解释将会有明显的改进.这有助于进一步认识Roper共振态的性质.     

Meson Effects on the Chiral Condensate at Finite Density

Meson corrections on the chiral condensate up to next-to-leading order in a 1/Nc expansion at finite densityare investigated in the NJL model with explicit chiral symmetry breaking. Compared with mean-field results, the chiralphase transition is still of the first order while the properties near the critical density for chiral phase transition are foundto change significantly.     

Meson Effects on the Chiral Condensate at Finite Density

Meson corrections on the chiral condensate up to next-to-leading order in a 1/N_c expansion at finite density are investigated in the NJL model with explicit chiral symmetry breaking. Compared with mean-field results, the chiral phase transition is still of the first order while the properties near the critical density for chiral phase transition are found to change significantly.     

B→Kη′中双胶子聚合机制的进一步研究

双胶子聚合机制可能解释B→Kη′反常大的分支比.然而由于我们对η′犂犂有效顶点知之甚少,微扰QCD的理论计算存在很大的不确定性.本文尝试了几种不同的η′犂犂形状因子,并将数值结果和实验相比较.我们发现,虽然我们对η′犂犂形状因子了解得很少,但是如果B→Kη′衰变中双胶子聚合机制确实很重要的话,B→K^*η′的分支比将为10^－5量级,这可以被将来的实验检验.     

有限温度真空极化与热背景介质的电磁性质

用有限温度场论方法,研究了真空极化的温度和密度效应及背景介质的电磁性质,严格计算了真空极化的有限温度、密度修正和热背景介质的介电常数与磁导率,给出了对任何温度和任何密度都适用的严格的解析表达式.     

B→D()π衰变的因子化参数与强作用位相差

利用Belle与CLEO实验组的最新实验数据,分析了B→D^(*)π衰变道的同位旋振幅与位相差,并确定了相关的因子化参数.结果表明这类衰变道中的强相互作用效应不可忽略,但是因子化近似对于单个同位旋振幅仍旧是合理与自洽的.     

Rare Decay B → Xsvv in the Two-Higgs-Doublet Model of Type-Ⅲ

In this paper, we calculated the new physics contribution to theoretically very clean rare decay B → Xsvvin the general two-Higgs-doublet model (model Ⅲ). Within the considered parameter space, we found that (a) thenew physics contribution can provide one to two orders of enhancement to the branching ratio B(B → Xsvv) and cansaturate the experimental bound on B(B → Xs vv) in some regions of the parameter space; (b) besides the CLEO data ofB → Xsγ, the ALEPH upper limit on B(B → Xsvv) also leads to further constraint on the size of the Yukawa couplingλtt: λtt ＜ 6.4 for λbb = 2.7 and mH+ = 200 GeV.     

2+1维格点QCD真空波函数的计算

用改进的格点哈密顿量和截断本征方程法计算2+1维QCD真空波函数,结果显示出良好的标度行为.     

Some Remarks on the Final State Interactions in B → πK Decays

Careful discussions are made on some points wfiich are met in studying B-decay final state interactions, taking the B⁰ → π + K^- process as an example. We point out that π-exchange rescatterings are not important, whereas for D^* and D^** exchanges, since the B₀ → D+D_s^-, decay has a large branching ratio their contributions may be large enough to enhance the B → πK branching ratio significantly. However our estimates fail to predict a large enhancement.     

光子偏振度受大气散射影响的分析

采用矩阵形式描述光子的偏振态和大气散射理论, 分析了“BB84协议”中四个不同偏振光子经单次散射后光子的偏振度与前向散射角的关系。发现单次散射不改变偏振光子的总偏振度, 但改变偏振光子的线偏振度与圆偏振度, 尤其对垂直偏振光子的线偏振度与圆偏振度改变明显; 当前向散射角小于0.25 rad时, 四个不同偏振光子的线偏振度基本保持不变, 量子信息仍然保持; 同时分析了大气散射对不同波长的垂直偏振光子线偏振度的影响, 发现长波光子偏振度保持度高。     

Skyrme张量相互作用对可能的等待点原子核β衰变半衰期的影响(英文)

使用基于Skyrme相互作用的HFB+QRPA模型研究N~82和126的同中子异位素链的β-衰变的半衰期。在计算中所使用的张量相互作用和同位旋标量（IS）对相互作用都是很好地被约束了的。比较了张量相互作用和IS对相互作用对半衰期的影响。IS对相互作用的强度与相应的同位旋矢量（IV）对相互作用的强度相当时,对N~82和126的同中子异位素链中有大的中子过剩的原子核的半衰期影响很微弱。而张量相互作用采用最近约束的强度时对半衰期的影响非常显著。The β-decay half-lives of N ~ 80 and 126 isotonic chains are calculated with HFB+QRPA models based on Skyrme force. In the calculations, the well constrained Skyrme tensor interaction and isoscalar spin-triplet (IS) pairing interaction are included so that to study their effects on the half-lives. The effects of tensor interaction and IS pairing interaction on the half-lives are compared. The IS pairing interaction with strength similar to that of isovector (IV) one produces only a trivial effect in N ~82 nuclei, and N ~126 nuclei with big neutron excess. While the tensor interaction with presently constrained strengths produces an obvious effect.     

表面等离激元对氮化硅薄膜中Tb3+离子荧光寿命的影响

利用等离子增强化学气相沉积和离子注入方法,制备了铽掺杂的氮化硅薄膜,然后利用磁控溅射和热处理工艺在薄膜上沉积了不同颗粒尺寸的银薄膜来研究表面等离激元共振对铽离子荧光寿命的影响.实验结果表明氮化硅中Tb³⁺离子的光致荧光最强峰在547 nm,而银薄膜的存在会明显降低稀土离子Tb³⁺的荧光寿命,其寿命的改变是由于银薄膜的表面等离激元改变了电磁场的分布,从而影响了系统的局域光模密度(PMD),理论计算的结果也验证了这一点.     

Proximity Effects of the Vacuum and Substrate on the Behavior of Ultrathin Epilayers

The present considerations are motivated by (i) the need to grow thin films with perfection in crystallinity and thickness uniformity, both of importance for purposes of device fabrication and the study of two-dimensional systems, and (ii) by the importance to understand the roles of vacuum and substrate proximity effects during the ultrathin growth stage, as these effects may be decisive in tailoring the final product. It is accepted (a) that the need is best served by growing epitaxially—a substrate proximity phenomenon—and (b) that the quality of epilayers depends greatly on the mode of misfit accommodation at the epilayer-substrate interface and on the mode of growth. In classical theoretical analyses of epitaxy, these modes are modeled in terms of the interfacial lattice misfit, the amplitudes of lateral variation of interfacial atomic interaction, defect energies of the bicrystal and the elastic properties of the epilayer. The aim of this paper is to report on and search for perspective of attempts to quantify—using embedded-atom method potentials—the effects of vacuum and substrate proximities on these modeling parameters. The objective is to focus attention on the fact that the ultrathin film values of these parameters may be significantly different from their bulk values, which have been employed in the past for predictive purposes.     

基于Sagnac/双Mach-Zehnder原理的分布式光纤传感系统的偏振态分析

运用琼斯矩阵分析法,建立了该分布式传感器系统在传感光纤双折射和外部事件共同作用下,传输光的偏振态对系统功率传输系数影响的数学模型.仿真分析了在传感光纤线性双折射和圆双折射共同作用下,传输光的偏振态对系统功率传输系数的影响,并提出了利用偏振控制器对输入偏振态进行控制,从而改善干涉信号输出的方法.