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Hidden-charm tetraquarks in a mixture model: Coupled-channel analysis with cc¯ and hadronic molecular components

Kotaro Miyake*

Yasuhiro Yamaguchi†

  • Department of Physics, Nagoya University, Nagoya 464-8602, Japan and Kobayashi-Maskawa Institute for the Origin of Particles and the Universe, Nagoya University, Nagoya, 464-8602, Japan

  • *Contact author: miyake@hken.phys.nagoya-u.ac.jp
  • †Contact author: yamaguchi@hken.phys.nagoya-u.ac.jp
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Phys. Rev. D 112, 036004 – Published 8 August, 2025

DOI: https://doi.org/10.1103/frsx-swwp

Abstract

The nature of the X(3872) and other exotic hadrons has been a subject of extensive investigation since the first observation of the X(3872) in 2003. While various theoretical models have been proposed, including hadronic molecular and compact tetraquark interpretations, some experimental evidence suggests that the X(3872) may be a mixture state of a hadronic molecule and a cc¯ core. In this work, we perform a systematic study of the hidden-charm tetraquark candidates X(3860), X(3872), and Z(3930) using a coupled-channel model that incorporates both cc¯ states and D(*)D¯(*) hadronic molecular components. The cc¯ sector is described based on the constituent quark model predictions for the χcJ(2P) (J=0, 1, 2) states, while the meson-meson interactions are modeled using pseudoscalar and vector-meson exchange potentials. The model parameters are fixed to reproduce the masses of the X(3872) and Z(3930), and the resulting framework is used to predict the mass and structure of the JPC=0++ state associated with the X(3860). Our results support the mixture interpretation of these exotic hadrons, exhibiting strong attractions from the transition potential between cc¯ and D(*)D¯(*) components. The molecular component is found to dominate in the X(3872), while the cc¯ component plays a more prominent role in the X(3860) and Z(3930).

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Phys. Rev. D 112, 036004– Published 8 August, 2025
  • Received 16 June 2025
  • Accepted 16 July 2025
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