A narrow pentaquark state, P_c(4312)^+, decaying to J/ψp, is discovered with a statistical significance of 7.3σ in a data sample of Λ_b^0→J/ψpK^- decays, which is an order of magnitude larger than that previously analyzed by the LHCb Collaboration. The P_c(4450)^+ pentaquark structure formerly reported by LHCb is confirmed and observed to consist of two narrow overlapping peaks, P_c(4440)^+ and P_c(4457)^+, where the statistical significance of this two-peak interpretation is 5.4σ. The proximity of the Σ_c^+D[over ¯]^0 and Σ_c^+D[over ¯]^*0 thresholds to the observed narrow peaks suggests that they play an important role in the dynamics of these states.
Observation of a Narrow Pentaquark State, P_c(4312)^+, and of the Two-Peak Structure of the P_c(4450)^+
Veltri, M;
2019
Abstract
A narrow pentaquark state, P_c(4312)^+, decaying to J/ψp, is discovered with a statistical significance of 7.3σ in a data sample of Λ_b^0→J/ψpK^- decays, which is an order of magnitude larger than that previously analyzed by the LHCb Collaboration. The P_c(4450)^+ pentaquark structure formerly reported by LHCb is confirmed and observed to consist of two narrow overlapping peaks, P_c(4440)^+ and P_c(4457)^+, where the statistical significance of this two-peak interpretation is 5.4σ. The proximity of the Σ_c^+D[over ¯]^0 and Σ_c^+D[over ¯]^*0 thresholds to the observed narrow peaks suggests that they play an important role in the dynamics of these states.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
