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Spectra of bcb¯c¯ tetraquark states from a diquark-antidiquark perspective

Zhen-Yang Wang1,*, Jing-Juan Qi2,1,†, Zhen-Hua Zhang3,‡, and Xin-Heng Guo4,§

  • 1Physics Department, Ningbo University, Zhejiang 315211, China
  • 2College of Information and Intelligence Engineering, Zhejiang Wanli University, Zhejiang 315101, China
  • 3School of Nuclear Science and Technology, University of South China, Hengyang, 421001, Hunan, China
  • 4School of Physical Science and Technology, Kunming University, Kunming 650214, China

  • *Contact author: wangzhenyang@nbu.edu.cn
  • †Contact author: qijj@mail.bnu.edu.cn
  • ‡Contact author: zhangzh@usc.edu.cn
  • §Contact author: xhguo@bnu.edu.cn
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Phys. Rev. D 112, 074038 – Published 28 October, 2025

DOI: https://doi.org/10.1103/skdp-g4ql

Abstract

Within the diquark-antidiquark framework, this study investigates the masses of ground-state tetraquarks composed of heavy charm (c) and bottom (b) quarks and antiquarks, using the Bethe-Salpeter formalism. We establish the Bethe-Salpeter equations for the fully heavy bcb¯c¯ tetraquarks to the leading order in 1/mQ expansion. These equations are subsequently solved numerically under the covariant instantaneous approximation with kernels containing scalar confinement and one-gluon exchange terms. Our results show that the spectra of all possible S-wave tetraquark states are above the corresponding two lowest meson decay thresholds via the quark rearrangement. This implies that the ground bcb¯c¯ tetraquark states should be broad.

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Phys. Rev. D 112, 074038– Published 28 October, 2025
  • Received 17 August 2025
  • Accepted 8 October 2025
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