Bridging doubly heavy tetraquark mass spectrum with heavy baryons utilizing heavy antiquark-diquark symmetry*

Abstract Motivated by the observation of the doubly charmed tetraquark , we present a systematic study of doubly heavy tetraquarks ( ) using heavy antiquark-diquark symmetry (HADS) within a constituent quark model. By calibrating model parameters to known hadron spectra and incorporating the effective mass formula, we predict the masses for 38 ground-state tetraquarks with , , and heavy quark pairs, including the non-strange, single-strange, and double-strange configurations with quantum numbers and . Notably, we identify several stable states below the relevant meson-meson thresholds, particularly in the sector. The explicit connection between the doubly heavy tetraquark and the heavy baryon spectra through HADS reduces model dependence and reveals the fundamental systematics in the heavy-quark hadron landscape.