Speaker
Description
We study the latest non-trivial resonant line-shape of $\eta(1405 /1475)$ in the $K \bar{K}\pi$ invariant mass spectrum measured by the BESIII. The possible existence of two isoscalar pseudoscalars around 1.4 ~1.5 GeV is in contradiction with the nonet structure in the SU(3) flavor symmetry. Nevertheless, the glueball assignment of the outnumbering state is not favored by the Lattice QCD calculations. Trying to make the minimum assumptions based on the radial excitation picture, and taking into account the open channel effects in the decays of $\eta(1405/ 1475)\to K\bar{K}\pi$, such as the intermediate $K^*\bar{K}+c.c.$, $a_0 \pi$, and $\kappa \bar{K}+c.c.$ channels, as well as the interference with $\eta(1295)$ and the non-resonant contributions, we can describe this non-trivial $K\bar{K}\pi$ spectrum with a set of reasonable parameters and without the introduction of an additional new state. Not only the total three-body and two-body spectra are fitted well, but also the shifted resonant line-shape of different partial waves of $K\bar{K}\pi$ decay. And with our best fitted parameters, we also have a good description on the $\eta \pi \pi $ spectrum. The mass of $\eta(1405)$ is fitted as 1.43 GeV, which is consistent with the peak positions in the $\gamma V$ spectra.
