Canonical interpretations of the newly observed Xi _c(2923)^0, Xi _c(2939)^0, and Xi _c(2965)^0 resonances

Qi-Fang Lü

doi:10.1140/epjc/s10052-020-08488-5

Abstract

Three neutral resonances Xi _c(2923)^0, Xi _c(2939)^0, and Xi _c(2965)^0 have been observed in the Lambda _c^+ K^- mass spectrum by the LHCb Collaboration. Given the Xi _c and Xi _c^prime mass spectra predicted by the constituent quark models, these three resonances are tentatively treated as the lambda -mode Xi _c(2S), Xi _c^prime (2S), Xi _c^{prime *}(2S), and Xi _c^prime (1P) states, and their strong decay behaviors are calculated within the ^3P_0 model. Our results indicate that the Xi _c(2923)^0 and Xi _c(2939)^0 can be clarified into the J^P=3/2^- and 5/2^-Xi _c^prime (1P) states respectively, and the Xi _c(2965)^0 can be regarded as the J^P=1/2^+Xi _c^prime (2S) state. Also, we suggest that the previous observed Xi _c(2930) may be the overlap of two structures Xi _c(2923) and Xi _c(2939), and the Xi _c(2970) should be the same state as Xi _c(2965). Other theoretical information on the missing Xi _c(2S), Xi _c^{prime *}(2S), and Xi _c^prime (1P) states may be helpful for future experimental searches.

Highlights

A charmed strange baryon c is composed of a heavy charm quark, a light up or down quark, and a strange quark
Under the classification of constituent quark model, the c baryons can be divided into two families, the antisymmetric flavor configuration 3 ̄ F and symmetric flavor configuration 6F
To distinguish these two families, the states with 3 ̄ F flavor part are denoted as c states, and the notation c stands for the states belonging to the 6F flavor configuration

Summary

Introduction

A charmed strange baryon c is composed of a heavy charm quark, a light up or down quark, and a strange quark. The strong decay behaviors of these low-lying c and c states have been studied by several works within the quark models [7,8,9,10,11,12,13,14], it is essential to clarify the newly observed c(2923)0, c(2939)0, and c(2965)0 resonances into the c or c family. The c(2930)0 which is absent in present experimental observation, may have caused lots of troubles in previous studies In this issue, we calculate the strong decay behaviors of the newly observed c(2923)0, c(2939)0, and c(2965)0 resonances under various assignments within the 3 P0 model. The 3 P0 model is adopted to estimate the strong decays of the c(2923)0, c(2939)0, and c(2965)0 resonances.

Experiments

Strong decays

Summary