2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/202996A fully reconstructed Bc --> Jpsi Pi signal is observed with the D0 detector at the Fermilab Tevatron p-pbar collider. Using 1.3 inverse femtobarns of integrated luminosity, the signal is extracted with a significance more than five standard deviations above background. The measured Bc meson mass is 6300 (+-) 14 (stat) (+-) 5 (sys) MeV/cc6 pages, 1 figure, submitted to Phys.Rev.LettHigh Energy Physics - Experimenttext