2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/49103In this talk we present a calculation of the dacay rate difference in the neutral $B_s-\bar{B}_s$ system, $ΔΓ_{B_s}$, in next-to-leading order (NLO) QCD. We find a sizeable decrease compared to leading-order (LO) estimates: $ (ΔΓ/Γ)_{B_s} = (f_{B_s}/210 MeV)^2 [0.006 B(m_b) + 0.150 B_S(m_b) - 0.0063]$ in terms of the bag parameters $B$ and $B_S$ in the NDR scheme. We put special emphasize on the theoretical and physical implications of this quantity.5 pages, uses JHEP.cls (included), talk given at the Corfu Summer Institute on Elementary Particle Physics (South European School on Elementary Particle Physics), 6-26 September 1998, Kerkyra, Greece (to appear in the proceedings)High Energy Physics - Phenomenologytext