相对论性电磁束缚系统（π±μ干）、（K±μ干）的库仑裂解与衰变

本文应用复合粒子量子场论的微扰展开式和相对论性的（π^&;#177;μ^?）、（K^&;#177;μ^?）的B.S.波函数,计算了在原子核屏蔽库仑场中高能（π^&;#177;μ^?）、（K^&;#177;μ^?）原子的裂解能谱和截面。在极端相对论近似下,对大多数原子核,它们的裂解截面分别约为10^-18cm²和10^-17cm²。利用同样的波函数,还计算了（π^&;#177;μ^?）→π⁰+v_μ（v_μ）,（K^&;#177;μ^?）→K⁰+v_μ（v_μ）,以及（π^&;#177;μ^?）→μ⁺+μ^-+v_μ（v_μ）,（K^&;#177;μ^?）→μ⁺+μ^-+v_μ（v_μ）的衰变几率。     

原子核中的△（1236）对（p,π+）反应的影响

我们假定了一个p→Δ⁰+π⁺的一核子模型,在平面波玻恩近似下,把Δ⁰波函数取为谐振子形式,计算了²⁶Mg（p,π⁺）²⁷Mg 反应的微分截面.为了比较,在同样近似下,对 p→n+π⁺的一核子模型,也做了计算.结果表明,两种机制给出的角分布,无论大小和形状都有明显的差别.对于Δ⁰波函数,我们还选取了高动量成分较大的 Eckart 形式,由计算结果看出,它比谐振子波函数有很明显的改进.这表明,（p,π⁺）反应对束缚态波函数的高动量成分很敏感.     

量子色动力学中的e++e-→π+q+q过程

本文利用QCD的渐近自由性质,求出一条腿动量平方固定另一条腿动量平方趋于无穷大时的波函数,并把它应用于计算e⁺+e^-→π+q+（?）过程（其中π介子相对于层子喷注轴有大的横动量）。计算结果表明,这个过程对e⁺+e^-→强子截面的贡献比e⁺+e^-→g+q+（?）过程的贡献小得多。     

关于（e+e-）,（μ+μ-）原子在库仑场的裂解

本文应用了复合粒子场论的微扰展开理论和自旋为（1/2-1/2）的库仑相互作用原子的Bethe-Salpeter协变波函数的近似解,计算了（e⁺e^-）（μ⁺μ^-）原子的高速飞行下裂解截面及能谱。结果表明（e⁺e^-）原子的裂解截面比前人的计算约小20％。此外,计算还表明（e⁺e^-）及（μ⁺μ^-）原子的单态和三重态裂解截面对任意主量子数n,和极端相对论近似下将精确相等,而前人的计算中只是n=2时才有这一结果,而对n=1时,两者相差约有25％。看来很可能是计算中的错误所致。     

Analysis of Bs→φμ+μ- decay within supersymmetry

Motivated by the rst measurement on B(B_s→φμ⁺μ^-) by the CDF Collaboration, we study the supersymmetric e ects in semi-leptonic B_s→φμ⁺μ^- decay. In our evaluations, we analyze the dependences of the dimuon invariant mass spectrum and the forward-backward asymmetry on relevant supersymmetric couplings in the MSSM with and without R-parity. The analyses show that the new experimental upper limits of B(B_s→φμ⁺μ^-)from the LHCb Collaboration could further improve the bounds on sneutrino exchange couplings and (δ_LL^u)₂₃ as well as (δ_LL,RR^u)₂₃ mass insertion couplings. In addition, within the allowed ranges of relevant couplings under the constraints from B(B_s→φμ⁺μ^-), B(B→K^(*)μ⁺μ^-) and (B_s→φμ⁺μ^-), the dimuon forward-backward asymmetry and the di erential dimuon forward-backward asymmetry of B_s→φμ⁺μ^-are highly sensitive to the squark exchange contribution and the (δ_LL^u)₂₃ mass insertion contribution. The results obtained in this work will be very useful in searching for supersymmetric signals at the LHC.     

从KL0产生（π±μ干）原子

本文求解了自旋是0-1/2的不等质量的库伦原子的Bethe-Salpeter方程。应用所求得的近似的B-S波函数以及近年来发展的复合粒子量子场论微扰展开理论计算了由K_L⁰产生（π^士μ^干）原子的几率。     

光生相对论的（μ+μ-）,（e+e-）仲原子

本文应用复合场论微扰展开式和相对论的 B-S 近似波函数,计算了类似于 Primakoff 效应的光生相对论的（e⁺e^-）,（μ⁺μ^-）仲原子的过程.结果与通常点模型的计算结果不同,这里多得出了一个新的形状因子.这表明在通常的Primakoff 效应中也将存在类似的修正.     

(0—3/2)电磁束缚系统的B-S方程及其近似解

本文在梯形近似和弱耦合条件下求解了(0—3/2)电磁束缚系统的Bethe-Salpeter方程, 给出了精确到0(α)量级的相对论协变的近似B-S波函数, 进而利用此波函数和复合粒子量子场论的微扰展开理论, 计算了Ω^－+p→(π⁺Ω^－)+n过程中(π⁺Ω^－)原子的最大产生截面. 其结果为σ_max≈4×10^－37cm².     

Fourth generation effects in Bs→π^-K^＋ decay

We study the effects of the fourth quark generation model in B_s → π^-K⁺ decay. Combining with the up-to-date experimental measurement for B(B_s → π^-K⁺) and A_cp^dir(B_s → π^-K⁺) by the CDF Collaboration, we derive the new bound of weak phase ø_bd, which are 0°< ø_bd <44°, 321°< ø_bd < 360° and 0°< ø_bd < 26°, 342°< ø_bd < 360° for m_t'=400 and 600 GeV respectively. In these regions, B(B_s → π^-K⁺) and A_cp^dir(B_s → π^-K⁺) consist with the current experimental data within errors.     

自旋1/2的正反费米子电磁束缚态的近似的B-S波函数

本文在梯形近似下,求解了自旋1/2的正反费米子电磁束缚态的Bethe-Salpeter方程.除得到标准的满足 Balmer 系的本征值外,还得到了明显具有相对论协变性,具有正确解析性,满足谱条件的近似的 B-S 波函数.以η⁰→γ+（e⁺e^-）和η⁰→γ+（μ⁺μ^-）为例,表明上述所得到的近似波函数能方便地用来计算相对论电磁束缚态的产生、湮灭和跃迁等问题.     

电子与极化核子的深度非弹散射过程与重轻子对产生过程的极化效应

本文利用文献[3]给出的具有一定自旋取向的层子的分布函数,计算了:1.电子与极化质子、中子、核子深度非弹散射过程的微分截面和不对称度;2.过程+N→μ⁺μ^-+X（其中和N都是极化的）的微分截面和不对称度,并从运动学证明了过程π（K）+N→μ⁺μ^-+X（其中核子N是极化的）没有极化效应,从部分子模型得到过程p+N→μ⁺μ^-+X（其中p和N是极化的）也没有极化效应。     

Pure annihilation type decays B0→Ds- K2+ and Bs→Da2 in perturbative QCD approach

We calculate the branching ratios of pure annihilation type decays B⁰→D_s^- K₂^*+ and B_s→Da₂ using the perturbative QCD approach based on k_T factorization. The branching ratios are predicted to be (60.6_{-16.5-10.4-2.1}^{+17.3+4.3+3.2} )× 10^-6 for B⁰→D_s^- K₂^*+, (1.1_-0.4-0.2-0.1^+0.4+0.1+0.1)×10^-6 for B_s→D⁰a₂⁰ and (2.3_-0.8-0.4-0.1^+0.8+0.2+0.1)×10^-6 for B_s→D^-a₂⁺. They are large enough to be measured in the ongoing experiment. Due to the shortage of contributions from penguin operators, there are no direct CP asymmetries for these decays in the Standard Model. We also derive simple relations among these decay channels to reduce theoretical uncertainties for the experiments to test the accuracy of theory and search of new physics signal.     

π核双电荷交换反应与核结构

用Glauber多次散射理论和相干涨落核模型,计算了能量在（3,3）共振区的π⁺介子在¹⁶O和¹⁸O靶核上引起的双电荷交换反应截面。理论计算的¹⁸O（π⁺,π^-）¹⁸Ne_g.s.和¹⁶O（π⁺,π^-）¹⁶Ne_g.s.反应截面的比值,很好的符合实验值。理论预言了¹⁸O（π⁺,π^-）¹⁸Ne_g.s.微分截面角分布在角度为23°附近有极小值,实验表明了这个极小的存在。     

Measurement of J/ψ decays into ΛΛ π+π-

Based on 58 million J/ψ events collected by the BESⅡ detector at the BEPC, J/ψ→ΛΛ π⁺π^- is observed for the first time. The branching fraction is measured to be Br(J/ψ→ΛΛ π⁺π^-)=(4.30±0.13±0.99)×10^-3, excluding the decays to intermediate states, namely J/ψ→Ξ^-Ξ⁺, J/ψ→Σ(1385)^-Σ(1385)⁺, and J/ψ→Σ(1385)⁺Σ(1385)^-. The branching fractions for these intermediate resonance channels are measured to be:Br(J/ψ→Ξ^-Ξ⁺)=（0.90±0.03±0.18）×10^-3, Br(J/ψ→Σ(1385)^-Σ(1385)⁺)=(1.23±0.07±0.30)×10^-3,and Br(J/ψ→Σ(1385)⁺Σ(1385)^-)=(1.50±0.08±0.38)×10^-3, respectively. The angular distribution is of the form dN/d(cosθ)α(1+αcos²θ) with α=(0.35±0.29±0.06) for J/ψ→Ξ^-Ξ⁺, α=(-0.54±0.22±0.10) for J/ψ→Σ(1385)^-Σ(1385)⁺, and α=(-0.35±0.29±0.06) for J/ψ→Σ(1385)⁺Σ(1385)^-.     

D介子衰变Γ（D0→K+K-）/Γ（D0→π+π-）

考虑强作用修正对D⁰介子衰变的影响,用Gilman和Wise^[1]的方法,导出ΔC=1的等效哈密顿量,算得Γ（D⁰→K⁺K^-）/Γ（D⁰→π⁺π^-）～1.26,简单讨论了这种计算方法中的一些问题。     

The study of B→K()l+l- decays in family non-universal Z' models

In a combined investigation of B→K^(*)l⁺l^- decays, constraints on the related couplings in family non-universal Z' models are derived. We find that within the allowed parameter space, the recently observed forward-backward asymmetry in the B→K^(*)l⁺l^- decay can be explained by flipping the signs of the Wilson coefficients C₉^eff and C₁₀. With the obtained constraints, we also calculate the branching ratio of the B_s→μ⁺μ^- decay. The upper bound of our prediction is nearly an order of magnitude smaller than the upper bound given by the CDF Collaboration recently.     

Analysis of Λb→pK- and pπ- decays in a flavor changing Z' mode

In this paper, we calculate the branching ratios of Λ_b→pK^- and pπ^- decays in the avor changing Z' model. We nd that the branching ratios for these two decay modes are sensitive to the contributions of the Z' boson. For Λ_b→pK^- decay, if the left-handed couplings are equal to the right-handed couplings, the branching ratio of this decay could match up to the currently experimental data for ξ_s=0.01 and -52°<φ_s^L<132°, or ξ_s=0.004 and 0°<φ_s^L<84°; if only the left-handed couplings are considered, it could match up to the experimental data for ξ_s=0.01 and -10°φ_s^L<138°. And for Λ_b→pK^- decay, if the left-handed and right-handed couplings are equal, the branching ratio of Λ_b→pK^- decay may be consistent with the currently experimental data with ξ_d=0.05 and -135°φ_d^L<43°, if only the left-handed couplings are considered, it may be consistent with ξ_d=0.05 and -114°φ_d^L<8°.     

α粒子模型下的π--12C散射

本文应用独立α粒子模型波函数,在Glauber理论下,计算了共振区内一系列能量（T_π=-120、150、180、220、260MeV）下的π^--¹²C弹性散射微分截面。理论与实验结果较好地符合。在截面对于波函数敏感的低能区域,本文结果比前人同类结果有明显改进。     

高山宇宙线荷电强子流强的负正比

在海拔3220米的实验室里,用磁谱仪动量予选装置和多板云室,对落在0.23m²面积上的单根荷电强子进行了观测.考虑到各种可能的修正以后,得出在10—20 GeV/c之间,荷电强子的负正比为:N^-/N⁺=0.53±0.05.当认为N⁺只包含有P和π⁺,N^-是π^-,而且N_π+/N_π-=1时,推算出N_π-/N_p=0.9±0.1.若π^-积分谱的形式为j（>p）=Kp^-r,估算出在5—20 GeV/c的动量范围,r（?）2.3.本文也对荷电强子的积分流强作了粗略的估计,其结果是:j_⊥^p+π（>12 GeV/c）=（7.4±0.7）×10^-5cm^-2·st^-1·s^-1.     

π+-16O弹性散射的微观计算

本文用π核散射的微观描述,计算了T_π^lab=240、343MeV时π⁺-¹⁶O弹性散射微分截面,定性地符合实验。