Doubly heavy tetraquarks in an extended chromomagnetic model

TL;DR

This paper uses an extended chromomagnetic model to systematically study doubly heavy tetraquark masses, identifying stable states and the importance of color configurations as quark mass differences increase.

Contribution

It introduces an extended chromomagnetic model to analyze doubly heavy tetraquarks and highlights the dominance of color-triplet configurations in ground states.

Findings

Identifies three stable doubly heavy tetraquark states below meson thresholds.

Shows the dominance of color-triplet configurations in ground states.

Finds the importance of color-triplet configurations increases with quark mass differences.

Abstract

Using an extended chromomagnetic model, we perform a systematic study of the masses of the doubly heavy tetraquarks. We find that the ground states of the doubly heavy tetraquarks are dominated by color-triplet $\ket{(qq)^{\bar{3}_{c}}(\bar{Q}\bar{Q})^{3_{c}}}$ configuration, which is opposite to that of the fully heavy tetraquarks. The combined results suggest that the color-triplet configuration becomes more important when the mass difference between the quarks and antiquarks increases. We find three stable states which lie below the thresholds of two pseudoscalar mesons. They are the $IJ^{P}=01^{+}$ $nn\bar{b}\bar{b}$ tetraquark, the $IJ^{P}=00^{+}$ $nn\bar{c}\bar{b}$ tetraquark and the $J^{P}=1^{+}$ $ns\bar{b}\bar{b}$ tetraquark.