Radiative decay of the Ξ(1620) in a hadronic molecule picture *

Abstract

Abstract Last year, the state, which is cataloged in the Particle Data Group (PDG) with only one star, was reported again in the final state by the Belle Collaboration. Its properties, such as the spectroscopy and decay width, cannot be simply explained in the context of conventional constituent quark models. This inspires an active discussion on the structure of this resonance. In this paper, we study the radiative decays of the newly observed assuming that it is a meson-baryon molecular state of and with spin-parity developed in our previous study. The partial decay widths of the molecular state into and final states through hadronic loops are evaluated using effective Lagrangians. The partial widths for is evaluated to be approximately keV, which may be accessible for the LHCb experiment. If is a molecule, the radiative transition strength is considerably small and the decay width is of the order of 0.01 eV. Future experimental measurements of these processes can be useful to test the molecule interpretations of the .