This effort concerns the spectrum of excited mesons and baryons and is a theoretical counterpoint to experimental efforts at Jefferson Lab and other facilities. At its core this effort is work towards developing an understanding of which constructions of quarks and gluons appear in the spectrum of hadrons, with that understanding being rooted in first-principles QCD through the numerical approach known as lattice QCD.
Successful past calculations have elucidated the role of gluonic excitations in the spectrum of mesons and baryons, while more recent work focuses on studying excited hadrons as they appear in experiment, as short-lived resonances which decay into lighter stable hadrons. Our group has been a pioneer in applying finite-volume formalisms to relate the discrete spectrum of states computed in lattice QCD calculations to the continuous scattering amplitudes measured in experiments. We perform cutting edge calculations of coupled-channel scattering, of three-body final states, and of systems in which external currents couple to resonating scattering channels.