Puzzle of the ${\Lambda }_c$ spectrum

Abstract

There is a puzzle in the ${\Lambda }_c^{+}$ family, i.e., one member with $J^P=3/2^{+}$ is missing in a $L=2$ multiplet which the heavy quark effective theory predicts, and $J^P$'s of ${\Lambda }_c(2765{)}^{+}$ and ${\Lambda }_c(2940{)}^{+}$ are unknown. Using a light diquark picture to calculate baryon masses, we study possible assignments of two ${\Lambda }_c$'s with unknown $J^P$ and the missing ${\Lambda }_c^{+}$ with $3/2^{+}$ for $L=2$, and we find the most probable possibility that the peak corresponding to ${\Lambda }_c(2880{)}^{+}$ actually includes a missing member with spin $3/2^{+}$ for $L=2$ and that quantum numbers of ${\Lambda }_c(2765{)}^{+}$ and ${\Lambda }_c(2940{)}^{+}$ are $2S(1/2^{+})$ and $2P(1/2^{-})$, respectively.

3 pages, 3 tables

Cited by in corpus (10)

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• Decay properties of $P$-wave charmed baryons from light-cone QCD sum rules
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• Newly observed ${\Lambda }_c(2860{)}^{+}$ at LHCb and its \emph{D}-wave partners ${\Lambda }_c(2880{)}^{+}$, ${\Xi }_c(3055{)}^{+}$ and ${\Xi }_c(3080{)}^{+}$
• $D^{(\ast )}N$ interaction and the structure of ${\Sigma }_c(2800)$ and ${\Lambda }_c(2940)$ in chiral effective field theory
• New ${\Lambda }_b(6072{)}^0$ state as a $2S$ bottom baryon
• Three-body decay of ${\Lambda }_c^{\ast }(2765)$ and determination of its spin-parity
• Electromagnetic probes revealing the inner structure of the ${\Lambda }_c(2940)$