2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/38051A new measurement of $R_b$ with the ALEPH detector at LEP using five mutually exclusive hemisphere tags is presented. The preliminary result is $R_b = 0.2158 \pm 0.0009 (stat.) \pm 0.0011 (syst.)$.5 pagesHigh Energy Physics - Experimenttext