Abstract:
A charmed baryon is a kind of baryon containing at least one charm quark. There exist abundant excited charmed baryons, and the study of charmed baryon spectroscopy is very important for understanding the dynamics of light quarks in the environment of a heavy quark, and for testing heavy-quark symmetry and the chiral symmetry of light quarks. The Λ
+c baryon is the lightest charmed baryon, which is an isospin singlet composed of one charm quark, one up quark and one down quark. Very recently, using a data sample of 770 million B
B events collected at Υ(4S) resonance in the Belle experiment, Japan, studies were performed on the decay
B0 → Σ
c (2455)
0, ++π
±p. A new structure has been found in the invariant mass distribution of Σ
c (2455)
0, ++π
± with a significance of 4.2σ including systematic uncertainty, which means that the probability of the emergence of this structure due to statistical fluctuation and various uncertainties is less than 0.002%. Its mass and width are measured to be (2913.8 ± 5.6 ± 3.8) MeV/
c2 and (51.8 ± 20.0 ± 18.8) MeV, respectively. No known excited charmed baryon can match the observed new structure. It is probably a new excited Λ
c baryon, tentatively named as Λ
c (2910)
+.