Radiative decay of the Ξ(1620) in a hadronic molecule picture * *Supported by the Science and Technology Research Program of Chongqing Municipal Education Commission (KJQN201800510), the Opened Fund of the State Key Laboratory on Integrated Optoelectronics (IOSKL2017KF19). Yin Huang want to thanks the support from the Development and Exchange Platform for the Theoretic Physics of Southwest Jiaotong University (11947404, 12047576),

Yin Huang,Hongqiang Zhu,Feng Yang

doi:10.1088/1674-1137/abfd28

Yin Huang, Hongqiang Zhu + Show 1 more

Open Access

https://doi.org/10.1088/1674-1137/abfd28

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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 .

Highlights

Searching for hadrons beyond the quark model becomes one of the most important topics in the community of hadron physics
With obtained above coupling constants, the radiative decay width of the Ξ(1620)0 into Ξ0γ, Ξγπ, and γK Λ that are shown in Fig. 1 and Fig. 2 can be calculated straightforwardly
Our study shows that the partial width of Ξ(1620)0 → γK Λ is rather small, weakly increasing with the xK Λ increasing

Summary

INTRODUCTION

Searching for hadrons beyond the quark model becomes one of the most important topics in the community of hadron physics. In the conventional quark model, a hadron is composed of qqas a meson or qqq as a baryon. It is natural to expect the existence of hadrons composed of more quarks, which are called exotic states. From the observed decay model, the Ξ(1620) is a conventional baryon composed of uss or dss. Its properties the spectroscopy and the decay width cannot be explained in the context of conventional constituent quark models [5,6,7]. A molecular state with a narrow width and a mass around 1606 MeV was predicted in the unitarized coupled channels approach [8,9,10,11].

THEORETICAL FORMALISM

NUMERICAL RESULTS AND DISCUSSIONS

SUMMARY