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1.
Using the sequential decay process m e+e- → J/ψ → ΛΛ, Λ → pπ-, Λ → pπ+ as an example, the procedure for deducing the full angular distribution is illustrated by adopting both the Jacob-Wick and Jackson conventions in the helicity formalism. To make sure that the final physical result is free of phase conventions, we point out that the coefficients that relate the angular momentum states in different coordinate systems of reference frames have to be taken into account properly in the procedure. The fact that those coefficients are constants suggests that the Jackson convention is favorable in dealing with the processes with sequential decays. 相似文献
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The angular distribution of energy for synchrotron radiation in low frequency band (ω 〈〈 we) is obtained by rigorously solving the Nicolo Tartaglia equation. The result shows that the critical angle increases with decreasing frequency, but it cannot exceed 90°. The relation between critical angle θc. and frequency is common covering all wavelengths. For the small angle case, it is consistent with the result obtained by Jackson. With the increase of emanative angle, the radiant intensity increases first, then decays. 相似文献
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Polarization and Angular Distribution of Ll X-Ray Following Inner-Shell 2p3/2 Photoionization of Magnesium-Like Ions 下载免费PDF全文
The inner-shell 2pa/2 photoionization and the subsequent decay of Mg-like Fe^14+, Cd^36+, W^62+ and U^80+ ions are studied theoretically within the multiconfiguration Dirac-Fock method and the density matrix theory. Special attention is paid to exploring the influence of the non-dipole terms which arise from the multipole expansion of the electron-photon interaction in the photoionization process. The results show that the non-dipole contribution to the total cross section, the magnetic sublevels cross section of the photoionization process, the degree of linear polarization and angular distribution of the subsequent characteristic x-ray radiation become more important with the increase of photons energy and atomic nuclear Z. Especially for the cross section and the degree of linear polarization, the non-dipole contribution arrives at 50% for U^80+ at four time energy threshold units. However, for the angular distribution, the maximum contribution does not exceed 4%, even for U^80+ ions. 相似文献
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在质子与48Ti,51V和52Cr反应的去弹截面、弹性散射角分布实验数据的基础上,获得了一组入射质子能量在150 MeV以下的质子与52Cr反应的光学势参数。应用光学模型、扭曲波玻恩近似理论、核内级联模型、蒸发模型、带宽度涨落修正的Hauser-Feshbach理论以及激子模型(含改进的Iwamoto–Harada模型)计算得到了质子与52Cr反应的所有截面、角分布、能谱和双微分截面。对理论计算结果与实验数据以及TENDL中的数据进行了比较分析,结果显示,理论计算结果与实验数据符合较好,且反应道截面优于TENDL的结果。 相似文献
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为了实验研究粲偶素ψ'级联衰变过程ψ'→γ'xcJ→γ'γJ/ψ,一个用于正确描述全部末态角分布的产生子是必要的.可以通过分析角分布的关联来确定这一过程的多极展开参数(或者等效的螺旋度振幅),而从中可以知道高阶电磁多极矩和相对论修正的贡献,同时可以检验ψ'是不是ψ'(2S)和ψ'(1D)的混合.介绍了一个能完全描述这一过程的角分布的产生子,同时讨论了测量多极参数的测量方法.这些都可以被用在BESⅢ或者CLEOc的分析当中. 相似文献
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完成了19F+27Al深部非弹性碰撞产物的角分布测量.初步分析了反应产B,C,N,O,F,Ne,Na,Mg和Al的实验室系角分布,展现出深部非弹性反应机制的特点,显示了反应系统随时间的演化过程. Angular distributions of fragments produced in the deep inelastic collision of~(19)F+~(27)Al have been measured for incident energy of 114 MeV at θ_(lab)= 9~(o), 24~(o), 40~(o), 55~(o), 70~(o) and 85~(o). Angular distributions of dissipative products B, C, N, O, F, Ne, Na, Mg and Al are analyzed to provide an evolution process of the intermediate dinuclear system formed in the reaction. 相似文献
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A sample of 1233 events is used to study the general characteristics of {}^{16}O-Em interactions at 4.5 A GeV/c. Multiplicity and angular distributions of slow particles and correlations among them are discussed. The present data are compared with the corresponding results from the interactions of other projectiles at the same energy and also the same projectile at different energies. The results indicate that black particle production is independent of the energy and mass of the projectile, but for grey particles it is dependent on the mass of projectile. 相似文献
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