2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/147958Quenched chiral perturbation is used to study the decay constants for heavy-light mesons beyond the leading order in 1/M. The results are used to estimate the error in quenched lattice calculations of the decay constants. For the double ratio $R_1 = ( f_{D_s}/f_D) / (f_{B_s}/f_B)$ we find that the error is small, conservatively 6%, but likely smaller. We also find that quenching decreases the ratio $f_{D_s}/f_D$ relative to the unquenched theory.14 pages, Latex, 6 postscript figures (included separately). Complete ps available at http://www.phys.ufl.edu/~booth/papers/quenched2.ps.gz . Minor changes to text in revised versionHigh Energy Physics - Phenomenologytext