2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/28705We investigate the conditions under which a gap vanishes in the spectrum of dimerized coupled spin-1/2 chains by means of Abelian bosonization and Lanczos diagonalization techniques. Although both interchain ($J'$) and dimerization ($δ$) couplings favor a gapful phase, it is shown that a suitable choice of these interactions yields massless spin excitations. We also discuss the influence of different arrays of relative dimerization on the appearance of non-trivial magnetization plateaus.5 pages, RevTex, 5 Postscript figuresStrongly Correlated Electronstext