2026/07/23 by Bing Chen, Ri-Qing Qian, Xiang Liu
#hep-ph
The K(1690) state with JP=0- was recently discovered by the COMPASS Collaboration in the scattering reaction K-+p→ K-π-π++p, leading to three observed pseudoscalar strange mesons, namely the K(1460), K(1690), and K(1830), in the 1.0-2.0 GeV region. However, within the quark model, only the 21S0 and 31S0 strange meson states are expected in this energy region. Therefore, at least one of these states should be interpreted as an exotic candidate. In this work, we study the spectrum of strange mesons systematically, and find that the K(1460) and K(1830) are good candidates of 21S0 and 31S0 strange mesons, respectively. A further investigation of their strong decays also supports this assignment. Furthermore, we note that the production mechanism of the K(1690) is similar to that of the π1(1600), which has been widely regarded as a hybrid meson candidate. We investigate the strong decays of the K(1690) within a constituent gluon model by treating it as a 0- strange hybrid meson and find that the results support the K(1690) as a hybrid state. Finally, we identify several important decay modes of the K(1690) that may be used in future experiments to test whether it contains the n1S0 (n=2 and 3) sq component. We also suggest BESIII to search for the K(1690) state through the J/ψ→ K K(1690) → KK∗0(1430)π→ KKππ process.