---
abstract: 'We study charmonium and bottomonium as relativistic bound states in a light-front quantized Hamiltonian formalism. The effective Hamiltonian is based on light-front holography. We use a recently proposed longitudinal confinement to complete the soft-wall holographic potential for the heavy flavors. The spin structure is generated from the one-gluon exchange interaction with a running coupling. The adoption of asymptotic freedom improves the spectroscopy compared with previous light-front results. Within this model, we compute the mass spectroscopy, decay constants and the r.m.s. radii. We also present a detailed study of the obtained light-front wave functions and use the wave functions to compute the light-cone distributions, specifically the distribution amplitudes and parton distribution functions. Overall, our model provides a reasonable description of the heavy quarkonia.'
author:
- Yang Li
- Pieter Maris
- 'James P. Vary'
title: Quarkonium as relativistic bound state on the light front
---

Introduction
============

Non-perturbative calculations of quantum chromodynamics (QCD) provide insights into the fundamental structure of hadrons which constitute the majority of the visible matter in the Universe. Lattice gauge theory has produced high precision results for hadron spectroscopy and many other observables. It is expected that Lattice QCD will eventually provide a valid description 