2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/41783In the covariant level-classification scheme of hadrons proposed recently, the existence of "chiral particles", scalar and axial-vector mesons as the partners of the ground-state pseudo-scalar and vector mesons, respectively, were predicted in the D and B meson systems, realizing a linear representation of chiral symmetry. In this work we reanalyze the D* pi mass spectra obtained through the Upsilon (4S) and Z0 decays to show a possibility for the D_1chi.6 pages, 2 eps figures, uses ptptex.styHigh Energy Physics - Phenomenologytext