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Hunting for $B \bar{B}$ molecular state $X_{b 0}$ via radiative transition of $ϒ (10753)$

Yuan-Jun Gao¹, Gang Li ^1,*, Shi-Dong Liu ^1,†, and Qi Wu^2,‡

¹College of Physics and Engineering, Qufu Normal University, Qufu 273165, China
²Institute of Particle and Nuclear Physics, Henan Normal University, Xinxiang 453007, China

^*Contact author: gli@qfnu.edu.cn
^†Contact author: liusd@qfnu.edu.cn
^‡Contact author: wuqi@htu.edu.cn

Phys. Rev. D 113, 094027 – Published 21 May, 2026

DOI: https://doi.org/10.1103/59l3-3wwk

Abstract

We investigate the radiative decay $ϒ (10753) \to γ X_{b 0}$ within the framework of nonrelativistic effective field theory (NREFT). The $ϒ (10753)$ is treated as an $S − D$ mixed state of the $ϒ (4 S)$ and $ϒ_{1} (3 {{}^{3}D}_{1})$ , while the $X_{b 0}$ is interpreted as a weakly bound $B \bar{B}$ molecule with $J^{P C} = 0^{+ +}$ . The decay process was assumed to occur via the intermediate meson loops involving the $S$ -wave $B^{(*)}$ and $P$ -wave $B_{1}^{(')}$ mesons. Our calculated results indicate that the decay $ϒ (10753) \to γ X_{b 0}$ is dominated by the $B_{1}^{(')}$ meson loops. The partial decay width is predicted to be 0.2–1.5 keV for a binding energy range of $ε_{X} = 0 - 10 MeV$ , corresponding to a branching fraction of $10^{- 6} - 10^{- 5}$ . The decay width is found to be insensitive to the full width of the $B_{1}^{'}$ meson. Our study suggests that the radiative decay of the $ϒ (10753)$ is a promising channel to search for the $X_{b 0}$ state, which is crucial for testing heavy quark symmetries and understanding the exotic hadron spectrum in the bottom sector.

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Phys. Rev. D 113, 094027– Published 21 May, 2026

Vol. 113, Iss. 9 — 1 May 2026

Received 5 January 2026
Accepted 1 May 2026

DOI: https://doi.org/10.1103/59l3-3wwk

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP³.

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Hunting for $B \bar{B}$ molecular state $X_{b 0}$ via radiative transition of $ϒ (10753)$

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Hunting for BB¯ molecular state Xb0 via radiative transition of ϒ(10753)

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Hunting for $B \bar{B}$ molecular state $X_{b 0}$ via radiative transition of $ϒ (10753)$