标题： 从对称性考虑推导 (e+e+e-e-) 系统低能态的量子数 显示英文标题

标题： Deduction of the quantum unmbers of low-lying states of the (e+e+e-e-) system from symmetry consideration

摘要： 该系统(e+e+e-e-)的低能谱特征和一组完整的量子数已根据对称性考虑得出。 预测了一个低能奇宇称L=1激发态的存在，其中两个电子的自旋耦合为s1=1，两个正电子的自旋耦合为s2=0（或s1=0，s2=1），以及一个低能偶宇称L=0激发态，其中s1=s2=1。 讨论已推广到二维(e+e+e-e-)系统。 显示英文摘要

摘要： The feature of the low-lying spectrum and a complete set of quantum numbers of the (e+e+e-e-) system have been deduced based on symmetry consideration. The existence of a low odd-parity L=1 excited state with the spins of the two electrons coupled to s1=1 and the two positrons coupled to s2=0 (or s1=0 and s2=1) and a low even-parity L=0 excited state with s1=s2=1 have been predicted. The discussion is generalized to 2-dimensional (e+e+e-e-) systems.