Λc重子谱疑难(英文)

Puzzle of the Λ_c Spectrum

Λ_c+重子家族存在一个疑难,也就是重夸克有效理论预言的轨道角动量为L=2的多重态中的态在实验上是缺失的,而且已发现的Λ_c(2765)+和Λ_c(2940)+的JP量子数仍然未知。在本工作中,我们使用双夸克图像计算了重子的质量,研究了Λ_c(2765)+和Λ_c(2940)+的可能归类以及仍缺失的具有L=2和量子数的Λ_c+态,进而指出Λ_c(2880)+的峰结构中实际上已经包含了L=2、这一缺失态,并建议Λ_c(2765)+和Λ_c(2940)+的量子数应分别为2S(1/2+)和2P(1/2-)。

There is a puzzle in the Λ＋ cfamily, i.e., one member with JP= 3/2＋is missing in a L =2 multiplet which the heavy quark effective theory predicts, and JP’s of Λ＋c（2765）＋and Λ_c（2940）are unknown. Using a light diquark picture to calculate baryon masses, we study possible assignments of two Λ_c’s with unknown JPand the missing Λ＋ cwith 3/2＋for L = 2, and we find the most probable possibility that the peak corresponding to Λ_c（2880）＋actually includes a missing member with spin 3/2＋for L = 2 and that quantum numbers of Λ_c（2765）＋and Λ_c（2940）＋are 2S（1/2＋） and 2P （1/2-）, respectively.