Exploration of the LHCb states and possible resonances in a unitary coupled-channel model

Chao-Wei Shen; Deborah Rönchen; Ulf-G. Meißner; Bing-Song Zou; Yu-Fei Wang

doi:10.1140/epjc/s10052-024-13139-0

2024 Impact factor 4.8

Particles and Fields

Open Access

Eur. Phys. J. C (2024) 84: 764
https://doi.org/10.1140/epjc/s10052-024-13139-0

Regular Article - Theoretical Physics I

Exploration of the LHCb $P_{c}$ states and possible resonances in a unitary coupled-channel model

Chao-Wei Shen¹^a, Deborah Rönchen¹, Ulf-G. Meißner¹^,2^,3, Bing-Song Zou⁴^,5^,6 and Yu-Fei Wang¹^,7

¹ Institute for Advanced Simulation (IAS-4), Forschungszentrum Jülich, 52425, Jülich, Germany
² Helmholtz-Institut für Strahlen- und Kernphysik and Bethe Center for Theoretical Physics, Universität Bonn, 53115, Bonn, Germany
³ Tbilisi State University, 0186, Tbilisi, Georgia
⁴ Department of Physics, Tsinghua University, 100084, Beijing, China
⁵ CAS Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, 100190, Beijing, China
⁶ School of Physics, University of Chinese Academy of Sciences (UCAS), 100049, Beijing, China
⁷ School of Nuclear Science and Technology, University of Chinese Academy of Sciences (UCAS), 101408, Beijing, China

^a c.shen@fz-juelich.de

Received: 12 May 2024
Accepted: 15 July 2024
Published online: 31 July 2024

Abstract

We extend our previous study of the interactions of ${\bar{D}}^{(*)} Λ_{c} - {\bar{D}}^{(*)} Σ_{c}^{(*)}$ $\bar{D}^{(*)} \Lambda _c - \bar{D}^{(*)}\Sigma _c^{(*)}$ within an analytic, unitary, coupled-channel approach by including the $J / ψ p$ $J/\psi p$ channel and performing fits to the $J / ψ p$ $J/\psi p$ invariant mass distributions in the $Λ_{b}^{0} \to J / ψ p K^{-}$ $\Lambda _b^0 \rightarrow J/\psi p K^-$ decay by the LHCb Collaboration. We take into account the contributions of t-channel pseudoscalar and vector meson exchanges and u-channel baryon exchanges in this work, and a series of bound states and resonances with different spin-parities are dynamically generated. According to the results, four states have a significant impact on the physical observables, with two having a spin-parity of $1 / 2^{-}$ $$1/2^-$$ and the other two having $3 / 2^{-}$ $$3/2^-$$ . These states can be associated with the LHCb hidden-charm pentaquarks. We further provide the coupling strength between each pole and different channels, which provides some insights on how to search for them in future experiments. Moreover, we also search for poles in higher partial waves up to $J = 7 / 2$ $$J=7/2$$ and find indications for the existence of several states with larger widths.

© The Author(s) 2024

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