Fully-heavy hadronic molecules $$B_c^{(*)+} B_c^{(*)-}$$ B c ( ∗ ) + B c ( ∗ ) - bound by fully-heavy mesons

Abstract A lot of exotic hadrons have been reported in the past twenty years, which bring us the renaissance of the hadron spectroscopy. Most of them can be understood as hadronic molecules, whose interactions are mainly due to the exchange of light mesons, and specifically, light vector mesons thro...

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Main Authors: Wen-Ying Liu, Hua-Xing Chen
Format: Article
Language:English
Published: SpringerOpen 2025-06-01
Series:European Physical Journal C: Particles and Fields
Online Access:https://doi.org/10.1140/epjc/s10052-025-14364-x
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author Wen-Ying Liu
Hua-Xing Chen
author_facet Wen-Ying Liu
Hua-Xing Chen
author_sort Wen-Ying Liu
collection DOAJ
description Abstract A lot of exotic hadrons have been reported in the past twenty years, which bring us the renaissance of the hadron spectroscopy. Most of them can be understood as hadronic molecules, whose interactions are mainly due to the exchange of light mesons, and specifically, light vector mesons through the coupled-channel unitary approach within the local hidden-gauge formalism. It is still controversial whether the interaction arising from the exchange of heavy mesons is capable of forming hadronic molecules. We apply the coupled-channel unitary approach to study the fully-heavy $$b {\bar{b}} c {\bar{c}}$$ b b ¯ c c ¯ system, where the exchanged mesons can only be the fully-heavy vector mesons $$J/\psi $$ J / ψ , $$B_c^*$$ B c ∗ , and $$\Upsilon $$ Υ . Especially, the $$J/\psi $$ J / ψ meson is much lighter than the $$B_c^{(*)}$$ B c ( ∗ ) mesons, so the present study can be taken as a general investigation on the question whether a lower-mass fully-heavy meson is able to bind two higher-mass fully-heavy hadrons. Our results suggest the existence of the fully-heavy hadronic molecules $$|B_c^{+} B_c^{-}; J^{PC}=0^{++} \rangle $$ | B c + B c - ; J PC = 0 + + ⟩ , $$|B_c^{*+} B_c^{-} - c.c.; J^{PC}=1^{+-} \rangle $$ | B c ∗ + B c - - c . c . ; J PC = 1 + - ⟩ , and $$|B_c^{*+} B_c^{*-}; J^{PC}=2^{++} \rangle $$ | B c ∗ + B c ∗ - ; J PC = 2 + + ⟩ as well as the possible existence of $$|B_c^{*+} B_c^{-} + c.c.; J^{PC}=1^{++} \rangle $$ | B c ∗ + B c - + c . c . ; J PC = 1 + + ⟩ . These states are potential to be observed in the $$J/\psi \Upsilon $$ J / ψ Υ , $$\mu ^+ \mu ^- J/\psi $$ μ + μ - J / ψ , and $$\mu ^+ \mu ^- \Upsilon $$ μ + μ - Υ channels in future ATLAS, CMS, and LHCb experiments.
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spelling doaj-art-59e40d949a87465aa7e9f8176faaa02d2025-08-20T02:39:44ZengSpringerOpenEuropean Physical Journal C: Particles and Fields1434-60522025-06-018561910.1140/epjc/s10052-025-14364-xFully-heavy hadronic molecules $$B_c^{(*)+} B_c^{(*)-}$$ B c ( ∗ ) + B c ( ∗ ) - bound by fully-heavy mesonsWen-Ying Liu0Hua-Xing Chen1School of Physics, Southeast UniversitySchool of Physics, Southeast UniversityAbstract A lot of exotic hadrons have been reported in the past twenty years, which bring us the renaissance of the hadron spectroscopy. Most of them can be understood as hadronic molecules, whose interactions are mainly due to the exchange of light mesons, and specifically, light vector mesons through the coupled-channel unitary approach within the local hidden-gauge formalism. It is still controversial whether the interaction arising from the exchange of heavy mesons is capable of forming hadronic molecules. We apply the coupled-channel unitary approach to study the fully-heavy $$b {\bar{b}} c {\bar{c}}$$ b b ¯ c c ¯ system, where the exchanged mesons can only be the fully-heavy vector mesons $$J/\psi $$ J / ψ , $$B_c^*$$ B c ∗ , and $$\Upsilon $$ Υ . Especially, the $$J/\psi $$ J / ψ meson is much lighter than the $$B_c^{(*)}$$ B c ( ∗ ) mesons, so the present study can be taken as a general investigation on the question whether a lower-mass fully-heavy meson is able to bind two higher-mass fully-heavy hadrons. Our results suggest the existence of the fully-heavy hadronic molecules $$|B_c^{+} B_c^{-}; J^{PC}=0^{++} \rangle $$ | B c + B c - ; J PC = 0 + + ⟩ , $$|B_c^{*+} B_c^{-} - c.c.; J^{PC}=1^{+-} \rangle $$ | B c ∗ + B c - - c . c . ; J PC = 1 + - ⟩ , and $$|B_c^{*+} B_c^{*-}; J^{PC}=2^{++} \rangle $$ | B c ∗ + B c ∗ - ; J PC = 2 + + ⟩ as well as the possible existence of $$|B_c^{*+} B_c^{-} + c.c.; J^{PC}=1^{++} \rangle $$ | B c ∗ + B c - + c . c . ; J PC = 1 + + ⟩ . These states are potential to be observed in the $$J/\psi \Upsilon $$ J / ψ Υ , $$\mu ^+ \mu ^- J/\psi $$ μ + μ - J / ψ , and $$\mu ^+ \mu ^- \Upsilon $$ μ + μ - Υ channels in future ATLAS, CMS, and LHCb experiments.https://doi.org/10.1140/epjc/s10052-025-14364-x
spellingShingle Wen-Ying Liu
Hua-Xing Chen
Fully-heavy hadronic molecules $$B_c^{(*)+} B_c^{(*)-}$$ B c ( ∗ ) + B c ( ∗ ) - bound by fully-heavy mesons
European Physical Journal C: Particles and Fields
title Fully-heavy hadronic molecules $$B_c^{(*)+} B_c^{(*)-}$$ B c ( ∗ ) + B c ( ∗ ) - bound by fully-heavy mesons
title_full Fully-heavy hadronic molecules $$B_c^{(*)+} B_c^{(*)-}$$ B c ( ∗ ) + B c ( ∗ ) - bound by fully-heavy mesons
title_fullStr Fully-heavy hadronic molecules $$B_c^{(*)+} B_c^{(*)-}$$ B c ( ∗ ) + B c ( ∗ ) - bound by fully-heavy mesons
title_full_unstemmed Fully-heavy hadronic molecules $$B_c^{(*)+} B_c^{(*)-}$$ B c ( ∗ ) + B c ( ∗ ) - bound by fully-heavy mesons
title_short Fully-heavy hadronic molecules $$B_c^{(*)+} B_c^{(*)-}$$ B c ( ∗ ) + B c ( ∗ ) - bound by fully-heavy mesons
title_sort fully heavy hadronic molecules b c b c b c ∗ b c ∗ bound by fully heavy mesons
url https://doi.org/10.1140/epjc/s10052-025-14364-x
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AT huaxingchen fullyheavyhadronicmoleculesbcbcbcbcboundbyfullyheavymesons