Evidence of a New Excited Charmed Baryon Decaying to Σ c ( 2455 ) 0 , + + π ±
We present the study of $\overline{B}$ 0 →Σ c (2455) 0,++ π ± $\overline{p}$ decays based on 772×10 6 B$\overline{B}$ events collected with the Belle detector at the KEKB asymmetric-energy e + e - collider. The Σ c (2455) 0,++ candidates are reconstructed via their decay to Λ$^{+}_{c}$π ∓ and Λ$^{+}_{c}$ decays to pK - π + , pK$^{0}_{S}$, and Λπ + final states. The corresponding branching fractions are measured to be $\mathscr{B}$($\overline{B}$ 0 →Σ c (2455) 0 π + $\overline{p}$)=(1.09±0.06±0.07)×10 -4 and $\mathscr{B}$($\overline{B}$ 0 →Σ c (2455) ++ π - $\overline{p}$)=(1.84±0.11±0.12)×10 -4 , which are consistent with the world average values with improved precision. A new structure is found in the M Σ c (2455) 0,++π± spectrum with a significance of 4.2σ including systematic uncertainty. The structure is possibly an excited Λ$^{+}_{c}$ and is tentatively named Λ c (2910) + . Its mass and width are measured to be (2913.8±5.6±3.8) MeV/c 2 and (51.8±20.0±18.8) MeV, respectively. The products of branching fractions for the Λ c (2910) + are measured to be $\mathscr{B}$($\overline{B}$ 0 →Λ c (2910) + $\overline{p}$) × $\mathscr{B}$(Λ c (2910) + →Σ c (2455) 0 π + )=(9.5±3.6±1.6) x 10 -6 and $\mathscr{B}$($\overline{B}$ 0 →Λ c (2910) + $\overline{p}$) × $\mathscr{B}$(Λ c (2910) + →Σ c (2455 )++ π - )=(1.24±0.35±0.10)×10 -5 . Here, the first and second uncertainties are statistical and systematic, respectively.