Lattice QCD calculations of hadron spectroscopy

TL;DR

This paper introduces lattice QCD as a computational approach to study hadron spectroscopy, detailing how hadron masses, widths, and scattering amplitudes are calculated from first principles, including both conventional and exotic hadrons.

Contribution

It provides a pedagogical overview of lattice QCD methods for determining hadron properties, emphasizing the extraction of scattering amplitudes and resonance parameters.

Findings

Determination of hadron masses and widths from lattice simulations

Extraction of scattering amplitudes for various hadrons

Analysis of both conventional and exotic hadron spectra

Abstract

This chapter provides a pedagogical introduction to theoretical studies of hadrons based on the fundamental theory of strong interactions - Quantum ChromoDynamics. A perturbative expansion in the strong coupling is not applicable at hadronic energy scales. Lattice Quantum Chromodynamics is the formulation of the fundamental theory on a discrete space-time grid, which enables first-principles, systematically improvable, numerical simulations of strong interaction physics. This chapter explains how the masses of strongly stable and strongly decaying hadrons are determined. The strongly decaying hadrons have to be inferred from the corresponding scattering processes. Therefore, one of the main aims is to describe how the scattering amplitudes are extracted from a lattice simulation. The examples of spectra, widths, and scattering amplitudes are shown for conventional as well as exotic hadrons.