2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/135363We report a precise measurement of masses of the $Ξ_c(2645)$ and $Ξ_c(2815)$ baryons using data collected by the Belle experiment at the KEKB $e^+ e^-$ collider. The states $Ξ_c(2645)^{0,+}$ are observed in the $Ξ_c^{+,0}π^{-,+}$ decay modes, while the $Ξ_c(2815)^{0,+}$ are reconstructed in the $Ξ_c(2645)^{+,0}π^{-,+}$ decay modes.15 pages, 4 figures, submitted to the ICHEP06 Conference, Moscow, RussiaHigh Energy Physics - Experimenttext