A highly significant structure is observed in the Λ_c^+K^-π^+π^+ mass spectrum, where the Λ_c^+ baryon is reconstructed in the decay mode pK^-π^+. The structure is consistent with originating from a weakly decaying particle, identified as the doubly charmed baryon Ξ_cc^++. The difference between the masses of the Ξ_cc^++ and Λ_c^+ states is measured to be 1334.94±0.72(stat.)±0.27(syst.) MeV/c^2, and the Ξ_cc^++ mass is then determined to be 3621.40±0.72(stat.)±0.27(syst.)±0.14(Λ_c^+) MeV/c^2, where the last uncertainty is due to the limited knowledge of the Λ_c^+ mass. The state is observed in a sample of proton-proton collision data collected by the LHCb experiment at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 1.7 fb^-1, and confirmed in an additional sample of data collected at 8 TeV.
Observation of the Doubly Charmed Baryon Ξ_cc^++
Veltri, M;
2017
Abstract
A highly significant structure is observed in the Λ_c^+K^-π^+π^+ mass spectrum, where the Λ_c^+ baryon is reconstructed in the decay mode pK^-π^+. The structure is consistent with originating from a weakly decaying particle, identified as the doubly charmed baryon Ξ_cc^++. The difference between the masses of the Ξ_cc^++ and Λ_c^+ states is measured to be 1334.94±0.72(stat.)±0.27(syst.) MeV/c^2, and the Ξ_cc^++ mass is then determined to be 3621.40±0.72(stat.)±0.27(syst.)±0.14(Λ_c^+) MeV/c^2, where the last uncertainty is due to the limited knowledge of the Λ_c^+ mass. The state is observed in a sample of proton-proton collision data collected by the LHCb experiment at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 1.7 fb^-1, and confirmed in an additional sample of data collected at 8 TeV.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
