Unified Spectroscopic Study of Bottom Mesons and Doubly Bottom Baryons Using a Relativistic Flux-Tube Model

Abstract

Using the relativistic flux tube (RFT) model with spin-dependent corrections, we present a unified investigation of the mass spectra for singly bottom mesons ($B$, $B_s$) and doubly bottom baryons ($Ξ_{bb}$, $Ω_{bb}$). Within this framework, the calculated masses for established $B$ and $B_s$ meson states show excellent agreement with experimental data. Leveraging these reliable predictions for low-lying states, we propose spectroscopic assignments for several higher excitations: we identify the $B_J^*(5732)$ resonance as an excellent candidate for the $1P(1^+)$ state; further, we assign the $B_J(5840)$ resonance as the first radial excitation ($2S$), and the $B_J(5970)$ resonance as a $1D$-wave orbital excitation. In the bottom-strange sector, we predict that the recently observed $B_{sJ}(6063)$ and $B_{sJ}(6114)$ resonances belong to the $1D$-wave multiplet. Extending our model to doubly bottom baryons, we present comprehensive predictions for the spectra of the $Ξ_{bb}$ and $Ω_{bb}$ baryons, identifying their ground and excited states. These theoretical insights serve as valuable benchmarks, offering guidance for future experimental searches targeting yet-to-be-discovered bottom mesons and doubly bottom baryons.