Spectroscopy and Radiative Decays of $Ω_{ccc}$ and $Ω_{bbb}$ Baryons in a Quark-Diquark Model
Chaitanya Anil Bokade, Bhaghyesh
TL;DR
This work addresses the spectra and radiative decays of triply heavy baryons Ω_ccc and Ω_bbb by employing a quark–diquark framework with a relativistic screened potential. The authors solve a two‑body bound‑state problem, first determining diquark masses and then treating the baryon as a diquark–quark system described by a Hamiltonian $H = \sqrt{-\nabla_{1}^{2} + m_{1}^{2}} + \sqrt{-\nabla_{2}^{2} + m_{2}^{2}} + V(r)$ with $V(r)=\tfrac{1}{2}V_V(r) + \tfrac{1}{2}V_S(r) + V_{SS}(r)$, where the running coupling $\alpha_s(r)$ and a spin‑dependent term $V_{SD}$ are included. Electromagnetic transitions are analyzed via a nonrelativistic expansion of the quark–photon interaction, yielding E1 and M1 operators, helicity amplitudes $\mathcal{A}$, and partial widths $\Gamma$ that depend on the photon energy $\omega_{\gamma}$. The study delivers complete $N_{d}L_{d}n_{q}l_{q}$ spectra and radiative widths, finding ground-state masses around $M(Ω_{ccc}) \approx 4.660$ GeV and $M(Ω_{bbb}) \approx 14.200$ GeV, with diquark excitations typically lowering masses relative to quark–diquark orbital excitations. Radiative decays reveal prominent transitions such as $Sp \rightarrow Ps$ and $Sd \rightarrow Ds$, while direct ground‑state E1/M1 transitions are suppressed, and the $Ω_{bbb}$ widths are roughly three orders of magnitude smaller than those of $Ω_{ccc}$ due to the smaller $b$-quark magnetic moment. Overall, the results align with several other theoretical approaches and provide valuable guidance for experimental exploration of triply heavy baryons and their internal diquark dynamics.
Abstract
We present a comprehensive study of the spectra and radiative decays of the triply heavy baryons $Ω_{ccc}$ and $Ω_{bbb}$ within a quark-diquark framework using a relativistic screened potential model. The analysis is carried out by solving a relativized Hamiltonian for a two-body bound system: the diquark masses are first determined, after which each baryon is treated as a composite of the diquark and the third quark. Employing the obtained wave functions, we calculate electromagnetic transitions using the E1 and M1 operators. We report complete $N_{d} L_{d} n_{q} l_{q}$ spectra together with E1/M1 decay widths for radially and orbitally excited states, and systematically compare our results with those from other theoretical approaches.