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

TL;DR

This work exploits heavy antiquark-diquark symmetry (HADS) within a constituent quark model to systematically predict the ground-state spectrum of 38 doubly heavy tetraquarks $T_{QQ'}\bar{q}\bar{q}'$ across $cc$, $bb$, and $bc$ sectors with $J^P=0^+,1^+,2^+$. By tying the tetraquark spectrum to known heavy-baryon spectra through HADS and using a unified mass formula calibrated to hadron data, the authors find a universal mass ordering $T_{QQ'}<T_{QQ'}\bar{s}<T_{QQ'}\bar{s}\bar{s}$ and typically reduced hyperfine splittings for heavier quarks. Notably, several $bb$-containing states lie below meson-meson thresholds, suggesting strong binding and potential stability, while $cc$ and $bc$ states are closer to thresholds, with $T_{cc}(3876)$ aligning with the observed near-threshold $T_{cc}^+(3875)$. The predictions, including mixing effects and HADS-breaking estimates, offer robust benchmarks to guide experimental searches and help distinguish compact tetraquarks from molecular interpretations. The approach demonstrates that HADS provides a fundamental, symmetry-grounded framework for organizing and predicting heavy-quark hadron spectra.

Abstract

Motivated by the observation of the doubly charmed tetraquark $T_{cc}(3875)^+$, we present a systematic study of double heavy tetraquarks ($T_{QQ'\bar{q}\bar{q}'}$) 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 $cc$, $bb$, and $bc$ heavy quark pairs, including the non-strange, single-strange, and double-strange configurations with quantum numbers $J^P = 0^+, 1^+$ and $2^+$. Notably, we identify several stable states below the relevant meson-meson thresholds, particularly in the $bb\bar{q}\bar{q}'$ sector. The explicit connection between doubly heavy tetraquark and heavy baryon spectra through HADS reduces model dependence and reveals fundamental systematics in the heavy-quark hadron landscape.

Figures (3)

• Figure 1: Mass spectrum and spin-parity of doubly charmed tetraquarks with nonstrange (red), single-strange (blue) and double-strange quarks (black).
• Figure 2: Mass spectrum and spin-parity of doubly bottomed tetraquarks with nonstrange (red), single-strange (blue) and double-strange quarks (black).
• Figure 3: Mass spectrum and spin-parity of bottom-charmed tetraquarks with nonstrange (red), single-strange (blue) and double-strange quarks (black).