Bottomonium spectroscopy motivated by general features of pNRQCD

Abstract

The bottomonium mass spectra is computed in the framework of potential non-relativistic quantum chromodynamics. The potential consists of a static term incorporating Coulombic plus confinement part along with a correction term added non-perturbatively from pNRQCD, which is classified in powers of the inverse of heavy quark mass \textit{O}$(1/m)$. The masses of excited bottomonia are calculated by perturbatively adding spin-hyperfine, spin-orbit and tensor components of one gluon exchange interactions in powers of \textit{O}$(1/m^2)$. Calculated masses are found to be consistent with other theoretical studies and experimental data. The Regge trajectories of the calculated mass spectra are also constructed. The values of the wave-functions are extracted and employed to calculate the electromagnetic transition widths and $\gamma\gamma$, $e^+e^-$, light hadron and $\gamma\gamma\gamma$ decay widths of several states at various leading orders, within the non-relativistic QCD formalism. Some of the experimentally reported states of bottomonium family like $\Upsilon$(10860), $\Upsilon$(11020) and X(10610) are identified as mixed $S-D$ wave and $P$-wave states.