Excited and exotic bottomonium spectroscopy from lattice QCD

TL;DR

This study uses lattice QCD to investigate the spectrum of excited and exotic bottomonium states, identifying conventional and hybrid states with specific quantum numbers and providing insights into their masses and structure.

Contribution

The paper presents the first lattice QCD analysis of excited and exotic bottomonium states, including hybrid supermultiplets with gluonic components and assigning continuum quantum numbers.

Findings

Identification of bottomonium states up to 11,000 MeV

Discovery of exotic states with non-$q\bar{q}$ quantum numbers

Hybrid supermultiplet with gluonic components approximately 1500 MeV above ground state

Abstract

We explore the spectrum of excited and exotic bottomonia using lattice QCD. Highly excited states are identified with masses up to 11,000 MeV, many of which can be grouped into supermultiplets matching those of the quark model while exotic spin--parity--charge-conjugation quantum numbers $J^{PC}=0^{+-},\,1^{-+},\,2^{+-}$ that cannot be formed from $\bar{q}q$ alone are also identified. Single-meson operator constructions are used that have good $J^{PC}$ in the continuum, these are found to overlap well onto heavy quark states with $J\le4$. A continuum $J^{PC}$ is assigned to each level, based on the distribution amongst lattice irreps and dominant operator overlaps. States with a dominant gluonic component are identified and form a hybrid supermultiplet with $J^{PC}=(0,1,2)^{-+},\, 1^{--}$, approximately 1500 MeV above the ground-state $\eta_b$, similar to previous computations with light, strange and charm quark systems.