Systematic exploration of triply heavy tetraquarks: spectroscopic and decay characteristics

Abstract

While hidden, singly, doubly, and fully heavy tetraquark states have been experimentally observed, triply heavy tetraquark states remain unconfirmed. We systematically investigate the spectroscopic and decay properties of four triply heavy-flavor tetraquark systems ($cc\bar{c}\bar{n}$, $cc\bar{c}\bar{s}$, $bb\bar{b}\bar{n}$, $bb\bar{b}\bar{s}$; $n=u,d$) based on the nonrelativistic quark model. Using an effective Hamiltonian, we employ the Gaussian expansion method to solve the four-body Schrödinger equation and incorporate the effect of color-spin configuration mixing. Results show both $cc\bar{c}\bar{q}$ and $bb\bar{b}\bar{q}$ systems have two $J^{P}=0^{+}$, three $J^{P}=1^{+}$, and one $J^{P}=2^{+}$ states, with ground-state masses of 5.2-5.5 GeV and 15.0-15.3 GeV, respectively. Root-mean-square radius analysis supports compact tetraquark configurations. All states are unstable, with rearrangement strong decays dominant and negligible radiative decays. Narrow resonances (e.g., $T_{c^{2}\bar{c}\bar{s}}(5360,0^{+})$, $T_{b^{2}\bar{b}\bar{n}}(15052,0^{+})$) arise from Feynman amplitude cancellation. We propose experimental searches in $J/ψD^{*}_{s}$/ $η_{c}D_{s}$ (5.3-5.4 GeV) and $ΥB^{*}$ (15.0-15.1 GeV) channels, providing key guidance for triply heavy tetraquark identification.

Figures (4)

• Figure 1: Spatial coordinates defined for the triply heavy tetraquark system $QQ\bar{Q}\bar{q}$ and its two-body rearrangement decays into meson-meson final states via quark interchange. Here, the meson-meson final state can form via two quark rearrangement pathways $B_{1}C_{1}$ ($(Q_{1}\bar{Q})(Q_{2}\bar{q})$) and $B_{2}C_{2}$ ($(Q_{2}\bar{Q})(Q_{1}\bar{q})$), as illustrated in the figure.
• Figure 2: Quark-interchange diagrams for the triply heavy tetraquark $QQ\bar{Q}\bar{q}$ decaying into meson-meson final states at the quark level. The curly line denotes the quark-(anti)quark interactions.
• Figure 3: Relative positions for the $cc\bar{c}\bar{n}$ (a) and $cc\bar{c}\bar{s}$ (b) tetraquark states labeled with horizontal solid lines, e.g. $5489(\Gamma=9)$ represents the mass and total decay width of the corresponding state (units: MeV). The numbers below the horizontal lines, e.g. $0.5:1.9:2.5$, represent the rearrangement decay partial widths of the corresponding state (units: MeV). The dotted lines denote various $S$-wave meson-meson thresholds, and the superscripts of the labels, e.g. $(J/\psi D^{*})^{2,1,0}$, represent the possible total angular momenta of the channels. The solid dots of different colors where the vertical dashed lines with arrows intersect the horizontal solid lines represent the allowed rearranged $S$-wave decay processes. The black dashed lines represent radiative transitions between different states, with the adjacent numbers denoting the corresponding radiative decay widths ( units: keV). For the $cc\bar{c}\bar{n}$ (a) tetraquark state, e.g. 0.5/21 represents the radiative decay widths of the $cc\bar{c}\bar{u}$ and $cc\bar{c}\bar{d}$ states, respectively, and the notation for their corresponding total widths follows the same convention.
• Figure 4: Relative positions for the $bb\bar{b}\bar{n}$ (a) and $bb\bar{b}\bar{s}$ (b) tetraquark states labeled with horizontal solid lines, e.g. $15238(\Gamma=11)$ represents the mass and total decay width of the corresponding state (units: MeV). The numbers below the horizontal lines, e.g. $0.1:4.2:2.9$, represent the rearrangement decay partial widths of the corresponding state (units: MeV). The dotted lines denote various $S$-wave meson-meson thresholds, and the superscripts of the labels, e.g. $(\Upsilon B^{*})^{2,1,0}$, represent the possible total angular momenta of the channels. The solid dots of different colors where the vertical dashed lines with arrows intersect the horizontal solid lines represent the allowed rearranged $S$-wave decay processes. The black dashed lines represent radiative transitions between different states, with the adjacent numbers denoting the corresponding radiative decay widths ( units: keV). For the $bb\bar{b}\bar{n}$ (a) tetraquark state, e.g. 80/22 represents the radiative decay widths of the $bb\bar{b}\bar{u}$ and $bb\bar{b}\bar{d}$ states, respectively, and the notation for their corresponding total widths follows the same convention.