海拔3220米动量大于4 GeV/c的μ子垂直积分动量谱

我们在云南海拔3220米高山上,利用G-M计数管磁谱仪,测量了动量大于4 GeV/c的宇宙线μ子垂直积分动量谱.实验给出的谱可用一指数函数表示:I（>P）=Q（p+4）^1.86±0.06(cm^-2·sr^-1·s^-1),其中动量P以GeV/c为单位,Q为常数.同时测量了动量在4—23 GeV/c范围μ子的荷电比为N_μ⁺/N_μ^-=1.26±0.11.另外对本谱仪的动量误差问题作了讨论和计算.     

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.     

Evidence for e+e-→γχc1,2 at center-of-mass energies from 4.009 to 4.360 GeV

Using data samples collected at center-of-mass energies of √s=4.009, 4.230, 4.260, and 4.360 GeV with the BES0 detector operating at the BEPC/ collider, we perform a search for the process e⁺e^-→γχ_c,j (J =0, 1, 2) and find evidence for e⁺e^-→γχ_c1 and e⁺e^-→γχ_c2 with statistical significances of 3.0σ and 3.4σ, respectively. The Born cross sections σ^B(e⁺e^-→γχ_c,j), as well as their upper limits at the 90% con dence level (C.L.) are determined at each center-of-mass energy.     

Transverse momentum spectra in high-energy nucleus-nucleus, proton-nucleus and proton-proton collisions

The transverse momentum distributions of final-state particles produced in nucleus-nucleus (AA), proton-nucleus (pA), and proton-proton (pp) collisions at high energies are investigated using a multisource ideal gas model. Our calculated results show that the contribution of hard emission can be neglected in the study of transverse momentum spectra of charged pions and kaons produced in Cu-Cu collisions at √s_NN=22.5 GeV. And if we consider the contribution of hard emission, the transverse momentum spectra of p and p produced in Cu-Cu collisions at √s_NN=22.5 GeV, K_s⁰ produced in Pb-Pb collisions at 158 A GeV, J/ψ particles produced in p-Pb collisions at 400 GeV and π⁺ , K⁺, p produced in proton-proton collisions at √s=200 GeV, can be described by the model, especially in the tail part of spectra.     

海平面宇宙线μ子垂直绝对强度及积分动量谱测量

利用两个大面积塑料闪烁计数器和两个液体闪烁计数器组成的望远镜系统与铅吸收体组成射程谱仪, 并用一个灵敏体积为70×50×30cm³的流光室作为剔除簇射装置, 1981年冬季, 对北京地区海平面宇宙线μ子垂直通量及其积分动量谱进行了测量. 动量测量范围为0.2 GeV/c至1.3 GeV/c μ子的垂直通量为9.2×10^－3sr^－1cm^－2s^－1. 在3.5×10⁴张照片进行了扫描判别, 可得簇射比例约占30%. 文中并对若干修正进行了讨论.     

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.     

弱电统一理论——SU(3)×U(1)模型

本文提出了一个对称性破缺前不仅左、右对称, 而且中微子(或反中微子)与荷电轻子、反轻子的弱作用也相同的SU(3)×U(1)模型. 这一模型无三角反常; 导出了sin²θ_w≤1/4; 在低能范围内与标准模型一致. 我们反轻子数推广为轻子荷. 证明了只有轻子荷才是严格守恒的, 各代轻子数分别守恒只能近似成立. 夸克不仅带有重子数、电荷, 而且也带有轻子荷. 本模型预言有μ_R→e_R+ν_eL+ν_μR, e^－+e^－→μ^－+μ^－等现象.     

一种层子和轻子的结构模型

提出了一种亚层子模型. 层子和轻子是由rishon T和V组成的. T和V是SU_H(3)×SU_C(3)×SU_G(2)×U(1)群的多重态. 由这些多重态可以自然地得到三代层子和轻子. 在此模型中质子衰变为μ^－e⁺e⁺或e^－μ⁺μ⁺.     

e+e-对撞中夸克喷注强子化的多重数结构

本文半唯象地基于无规独立产生子夸克和相空间考虑的简单图象,计算了S^1/2～4—7GeV能区的夸克喷注强子化的强子纵动量和能量分布S/β dσ/dx_p和S/β dσ/dx_E行为。它们与实验符合得相当好,本文还给出喷注中两个粒子关联截面dσ/(dx_1Edx_2E),有待实验检验。     

15C的中子晕结构研究

实验测量了83A MeV ^14,15C的核反应总截面(σ_R)及¹⁵C产生^14,15C和¹⁴C产生¹³C的动量分布(P_//). 分析得到了¹⁵C产生¹⁴C和¹³C的动量分布半高宽(FWHM)分别为71±9MeV/c和223±28MeV/c, 而¹⁴C产生¹³C的FWHM为195±21MeV/c. 从¹⁵C和¹⁴C产生¹³C的FWHM与Goldhaber模型的预言基本一致. 而¹⁵C产生¹⁴C的FWHM却要比该模型计算小得多. 同时观测到¹⁵C的σ_R比相邻核有反常增加. 在Glauber模型框架中, 对实验测得的P_//和σ_R进行了探讨. P_//和σ_R的分析结果同时显示¹⁵C的最后一个中主要处于s_1/2态, 具有中子晕结构.     

(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.     

不等质量(1/2—1/2)或(1/2-1/2)电磁束缚系统的近似B.S.波函数

本文求解了不等质量(1/2—1/2)电磁束缚系统的Bethe-Salpeter方程. 给出了这类系统的近似B.S.波函数. 利用复合粒子量子场论的微扰展开, 在精确到O(α)的量级下, 计算了Ξ⁰→(Σ⁺μ^－)+ν_μ的衰变率和分支比, 结果是wΞ⁰→(Σ⁺μ^－)+ν_μ=1.12(1/秒)R=[wΞ⁰→(Σ⁺μ^－)+ν_μ]/[wΞ⁰→(Σ⁺μ^－)+ν_μ]≥4.7×10^－7. 类似地, 还讨论了Λ→(pμ^－)+ν_μ过程.     

Searching for a neutral top-Higgs in association with top-quark pairs at an e~+e~- collider in the TC2 model

We investigate the associated production of the neutral top-Higgs h_t⁰ with a pair of top-quarks in the context of the topcolor-assisted technicolor (TC2) model at the future e⁺e^- Linear Colliders (LC) i.e. e⁺e^- → tt h_t⁰. We calculate the production rate and present the distributions of the transverse momenta of top-Higgs and top-quarks. The results show that the total cross section is typically of the order of 1.0-7.5 fb in the energy range between 1000 GeV and 2000 GeV of the LC for the whole top-Higgs mass region of interest. It should be distinctly possible that hundreds or even thousands of h_t⁰ signals can be produced per year at the LC given the luminosity L=500 fb^-1.     

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。     

Systematic analysis of DJ(2580), DJ(2650), DJ(2740), DJ(2760), DJ(3000) and DJ(3000) in the D meson family

In this work, we tentatively assign the charmed mesons D_J(2580), D_J^*(2650), D_J(2740), D_J^*(2760), D_J(3000) and D_J^*(3000) observed by the LHCb collaboration according to their spin, parity and masses, then systematically study their strong decays to ground state charmed mesons plus pseudoscalar mesons with the ³P₀ decay model. Based on these studies, we assign the D_J^*(2760) as the 1D(5/2)3^- state, the D_J^*(3000) as the 1F(5/2)2⁺ or 1F(7/2)4⁺ state, the D_J(3000) as the 1F(7/2)3⁺ or 2P(1/2)1⁺ state in the D meson family. As a byproduct, we also study the strong decays of the states 2P(1/2)0⁺, 2P(3/2)2⁺, 3S(1/2)1^-, 3S(1/2)0^- etc, which will be valuable in searching for the partners of these D mesons.     

Kerr-Newman度规中带电Bose子束缚态

本文指出, 无质量Bose子和Kerr-Newman黑洞不形成束缚态. 有质量的Bose子, 在0<α<√M²－Q²的情况下, 若E≠am+eQr₊/2Mr₊－Q²则无束缚态; 若E=am+eQr₊/2Mr₊－Q²则非束缚态存在的必要条件是(22)和(24)式. 在a=√M²－Q²的情况, 束缚态的能量E=√M²－Q²+eQM/2M²－Q², 当Q=0或者e=0时, 本文结论与de Felic^[1]和章世伟、苏汝铿^[2]的结果相符.     

BES端盖簇射计数器模型的束流测试

研制并测试了一台铅板和自猝灭流光管夹层式的气体取样簇射计数器. 计数管使用了铝方管和阳极丝读出. 能量分辨σ/E在E_e=1GeV时达15.5%, 能量响应范围是0—2GeV. 本文描述了束流测试的方法和计数器模型的各种性能.     

Fe:LiNbO3全息图热定影及H+浓度的影响

应用光折变效应动力学方程,导出了在Fe:LiN_bO₃中对光折变全息图热定影所需的最小H⁺浓度,以及H⁺浓度与光栅空间频率的关系.应用光谱比较法测量了不同样品的H⁺浓度值.得出了进行有效热定影的H⁺浓度范围.完成了Fe:LiN_bO₃全息存储和热定影实验.获得了100h连续无损读出的良好热定影实验结果.     

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。     

THE NEGATIVE-POSITIVE RATIO OF CHARGED COSMIC RAY HADRONS AT THE 3220 m ABOVE SEA-LEVEL

Single tracks of unaccompanÏed charged hadrons, within a horigontal area of 0.23m² have been measured with a magnetic spectrometer, a pre-selector of momentum in combination with a multiplate cloud chamber in a laboratory at 3220m above sea level. Taking various possible corrections into account, the negative-positive ratio of charged hadrons was obtained as N^-/N⁺=0.53±0.05 in the momentum range of 10-20 GeV/c. If we considered N⁺ contained only P and π⁺, N^-were π^-and that N_π+/N_π-=1, we deduced the result N_π-/N_p=0.9±0.1. Taking the form of the π^-integral spectrum as j（>p）=Kp^-γ, it was estimated that γ（?）2.3 in the momentum range 5—20 GeV/c. In this paper the integral verticel flux intensity of all charged hadrons was also estimated roughly, the result is:j_⊥^p+π（>12 GeV/c）=（7.4±0.7）×10^-5/cm²·sг·s_^.