Multi-Hadron Scattering from Lattice Quantum Chromodynamics
arXiv:2607.12508
The thesis develops lattice QCD techniques for constructing multi‑hadron operators and relating finite‑volume spectra to infinite‑volume scattering amplitudes, applying them to coupled‑channel Dπ scattering, three‑pion decays of the ω(782) and π(1300), and radiative and semileptonic decays of charmed mesons.
Abstract
This thesis develops lattice-QCD methods for studying hadron structure, scattering, and decays, with particular emphasis on multi-hadron resonances. The \texttt{Mathematica} package \texttt{OpTion} is developed to automate the construction of lattice multi-hadron operators. Finite-volume spectra are related to infinite-volume amplitudes through quantization conditions. For coupled-channel scattering, the pion-mass dependence of the pole trajectories and the scattering length are determined, and the results support a two-pole structure for the . The thesis then studies the three-pion decay of the . Two- and three-body spectra are calculated, and three-body quantization conditions and effective field theory descriptions are developed. The extracted resonance pole, extrapolated to the physical point, gives a mass and width consistent with experiment and establishes a practical first-principles procedure for interacting three-body systems. These methods are further applied to the , providing, for the first time, first-principles predictions of its resonance pole at several pion masses and revealing significant three-body effects. Finally, radiative and semileptonic decays of charmed mesons are investigated, and a model-independent method is developed to extract transition form factors with improved precision. These results advance the first-principles study of coupled-channel and three-body hadron resonances and provide new insight into their structure and decays.
Ph.D. thesis, Peking University, 2026. English translation of the original Chinese version