Quark models
Whether states like , , and are compact tetraquarks or hadronic molecules can only be settled by treating both configurations on equal footing. We solve the four-body Schrödinger equation in the quark potential model — benchmarking AL1/AP1 against the Gaussian expansion method and confirming — then extend the framework to resonances via the complex scaling method. A new definition of the root-mean-square radius exposes internal quark clustering, letting us cleanly distinguish compact from molecular configurations and predict new partner states awaiting experimental discovery.
Hadronic interaction
Many exotic hadron candidates near hadron-hadron thresholds — , — are dominated by coupled-channel effects that obscure their pole structure. We developed an improved complex scaling method (ICSM) that reveals poles inaccessible to the conventional CSM, and applied it to track the origins of and . Our analysis ties the dynamical origin of to its pole width and predicts a new resonance whose discovery would settle whether the state is a molecule or a shadow pole of a -wave charmonium.
Electromagnetic properties
Electromagnetic polarizabilities encode how a hadron's charge and current distributions respond to external electromagnetic fields, and they are uniquely sensitive to the internal structure of heavy hadrons. Despite their importance, the polarizabilities of heavy baryons have received little theoretical attention compared to radiative decays and magnetic moments. We computed the electric and magnetic polarizabilities of spin- singly heavy baryons in heavy-baryon PT to , finding that long-range chiral loops give significant corrections and that magnetic-dipole transitions make outsized contributions to the magnetic sector.
Production and decays
Beyond mass and width, the production mechanism of an exotic state in weak decays of and mesons offers an independent fingerprint of its nature. We computed branching fractions for and production in decays using the factorization approach combined with final-state interactions and rescattering, obtaining branching fractions of order – and ratios that depend only weakly on model parameters. These predictions are sharp enough to guide ongoing searches at Belle II and LHCb.