Speaker
Description
Radiative transitions between strongly stable hadrons and hadronic resonances offer a direct probe of the charge distribution within the resonance and can provide insightful revelations on the composition of hadronic resonances. This talk presents a toy-model investigation on the determination of 1 to 2 infinite-volume transition amplitudes from finite-volume matrix elements as would be performed in lattice QCD calculations. While the necessary formalism exists, there remains a challenge: most resonances couple to multiple two-hadron channels. Due to the reduction of rotational symmetry and the absence of asymptotic states in finite-volume Euclidean space-time, there is no one-to-one correspondence between the desired 1 to 2 infinite-volume coupled-channel transition amplitudes and the readily available finite-volume matrix elements of external currents. We show that by using parameterizations of the amplitudes that satisfy analyticity and unitarity, reasonable reconstruction of the underlying amplitude given sufficient effort is possible.
Based on work in progress in collaboration with
R. Briceño, J. Dudek, B. Slimmer
(for the Hadron Spectrum Collaboration)
