Doubly Heavy Tetraquarks in QCD Sum Rules

TL;DR

This paper uses QCD Sum Rules to investigate the masses and structures of doubly heavy tetraquarks, confirming their potential existence and analyzing their decay channels with detailed non-perturbative contributions.

Contribution

It provides a comprehensive QCD Sum Rules analysis of doubly heavy tetraquarks, including both bottom and charm states, with detailed mass predictions and decay channel analysis, extending previous lattice results.

Findings

Bottom tetraquark masses around 11.28-11.34 GeV for octet configurations.

Molecular configurations have masses below two-meson thresholds.

Decay channels and strong decay rates are analyzed for these tetraquarks.

Abstract

In the framework of QCD Sum Rules we investigate the $q q^\prime \bar{Q} \bar{Q}$ tetraquark structure with quantum number $J^P = 1^+$, which are embedded in two types of configurations, the $[8_c]_{q \bar{Q}} \otimes [8_c]_{q^\prime \bar{Q}}$ and $[1_c]_{q \bar{Q}} \otimes [1_c]_{q^\prime \bar{Q}}$ with $Q = b, c$, $q = u$, and $q^\prime = d, s$. Our finding confirms the Lattice QCD result that the bottom tetraquark states could exist and their masses are evaluated. In the calculation, the non-perturbative condensate contributions up to dimension eight in operator product expansion are considered, and those terms linear to the strange quark mass $m_s$ are kept. It is found that for octet-octet configuration the masses of potential tetraquark states are about $11.28$ GeV for the $ud\bar{b}\bar{b}$ system, and $11.31$ and $11.34$ GeV for the $us\bar{b}\bar{b}$ system, which are above the corresponding two-meson thresholds. For molecular configuration, the corresponding masses are found below the thresholds, that is $10.36$ GeV and $10.48$ GeV, respectively. The possible tetraquark decay channels are analyzed and the strong decay rates are evaluated. The mass dependence on the radiative correction and the condensates is estimated. Moreover, the doubly charmed tetraquark states are also considered.