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A coupled-channel perspective analysis on bottom-strange molecular pentaquarks

Qing-Fu Song, Qi-Fang Lü, Xiaonu Xiong

TL;DR

The paper tackles open-bottom bottom-strange molecular pentaquarks by combining a one-boson-exchange description of Y_b(, )  with a complex scaling method to locate bound and resonant poles in coupled-channel systems. It systematically analyzes Y_b   and Y_b K^{(*)} configurations, identifying a bound state near 6222 MeV that can be associated with Xi_b(6227) and predicting a flavor-exotic bound state in the 6300 MeV region. The study highlights strong coupled-channel and S-wave effects as crucial for binding and resonance formation, with pion exchanges playing a key role in certain channels. The results offer concrete targets for experimental searches and provide a framework for interpreting near-threshold bottom-strange hadrons in terms of molecular configurations guided by heavy-quark and hadronic interaction dynamics.

Abstract

At present work, we systematically study various bottom-strange molecular pentaquarks to search for possible bound states and resonances by adopting one-boson-exchange model within complex scaling method. According to our calculations, we predict several bound and resonant states for bottom baryon $Y_{b}(Λ_b,Σ_b) \bar K^{(*)}$ and $Y_{b} K^{(*)}$ systems. In particular, a bound state in the $I(J^P)=1/2(1/2^-)$ $Σ_{b}\bar{K}/Λ_{b}\bar{K}^*/Σ_{b}\bar{K}^*$ system may correspond to the particle $Ξ_{b}(6227)$. Meanwhile, the predicted bound state with $6303\sim6269~\rm{MeV}$ in the $I(J^P)=1/2(1/2^-)Σ_bK/Λ_bK^*/Σ_bK^*$ system is flavor exotic and does not appear in the spectroscopy of conventional baryons, which provides a practical way to clarify the nature of particle $Ξ_b(6227)$. We highly hope that our proposals can offer helpful information for the future experimental searches.

A coupled-channel perspective analysis on bottom-strange molecular pentaquarks

TL;DR

The paper tackles open-bottom bottom-strange molecular pentaquarks by combining a one-boson-exchange description of Y_b(, )  with a complex scaling method to locate bound and resonant poles in coupled-channel systems. It systematically analyzes Y_b   and Y_b K^{(*)} configurations, identifying a bound state near 6222 MeV that can be associated with Xi_b(6227) and predicting a flavor-exotic bound state in the 6300 MeV region. The study highlights strong coupled-channel and S-wave effects as crucial for binding and resonance formation, with pion exchanges playing a key role in certain channels. The results offer concrete targets for experimental searches and provide a framework for interpreting near-threshold bottom-strange hadrons in terms of molecular configurations guided by heavy-quark and hadronic interaction dynamics.

Abstract

At present work, we systematically study various bottom-strange molecular pentaquarks to search for possible bound states and resonances by adopting one-boson-exchange model within complex scaling method. According to our calculations, we predict several bound and resonant states for bottom baryon and systems. In particular, a bound state in the system may correspond to the particle . Meanwhile, the predicted bound state with in the system is flavor exotic and does not appear in the spectroscopy of conventional baryons, which provides a practical way to clarify the nature of particle . We highly hope that our proposals can offer helpful information for the future experimental searches.
Paper Structure (17 sections, 17 equations, 5 figures, 5 tables)

This paper contains 17 sections, 17 equations, 5 figures, 5 tables.

Table of Contents

  1. introduction
  2. Formalism of effective interaction and complex scaling method
  3. The effective interactions
  4. Complex scaling method
  5. Results and discussions
  6. Bottom baryon and anti-strange meson systems
  7. $I(J^{P})=1/2(1/2^-)$ with $\Sigma_{b}\bar{K}/\Lambda_{b}\bar{K}^*/\Sigma_b\bar{K}^*$
  8. $I(J^{P})=3/2(1/2^-)$ with $\Sigma_{b}\bar{K}/\Sigma_b\bar{K}^*$
  9. $I(J^{P})=1/2(3/2^-)$ with $\Lambda_{b}\bar{K}^*/\Sigma_b\bar{K}^*$
  10. $I(J^{P})=3/2(3/2^-)$ with $\Sigma_b\bar{K}^*$
  11. Bottom baryon and strange meson systems
  12. $I(J^{P})=1/2(1/2^-)$ with $\Sigma_b K / \Lambda_b K^* / \Sigma_b K^*$
  13. $I(J^{P})=3/2(1/2^-)$ with $\Sigma_b K / \Sigma_b K^*$
  14. $I(J^P) = 1/2(3/2^-)$ with $\Lambda_b K^* / \Sigma_b K^*$
  15. $I(J^P) = 3/2(3/2^-)$ with $\Sigma_b K^*$
  16. ...and 2 more sections

Figures (5)

  • Figure 1: A sketch of heavy superflavor symmetry between $\Sigma_b(\Lambda_b)K^{(*)}$ pentaquarks and $\bar{B}K^{(*)}$ tetraquarks. $q$ stands for the light quarks ($u$ or $d$).
  • Figure 2: Schematic eigenvalue distributions of $H_\theta$ in the coupled-channel two-body systems.
  • Figure 3: The $\Lambda$ dependence for the bottom-strange pentaquarks systems. The red solid dots stand for the bound states. The blue open circles with bars correspond to the resonances, with the lengths of bars being the total widths of the corresponding resonances.
  • Figure 4: The complex energy eigenvalues of $I(J^P)=1/2(1/2^-)$ system by varying the angle $\theta$ from $30^\circ\sim40^\circ$.
  • Figure 5: (Color online) The $r$ dependence of the deduced effective potentials with cutoff of 1000 $\rm{MeV}$ for the $S-$wave $\Sigma_b\bar{K}^*$ system with $I(J^P)=1/2(1/2^-)$.