Speaker
Description
In the last ten years, a whole set of new particles not fitting in the constituent quark model has populated the mass region above the
open-charm threshold. The spectrometer BESIII, installed at the Beijing Electron Positron Collider II, can access these states in electron-positron annihilations both by production and by direct formation. It has collected a large dataset at different center-of-mass energies. In this talk, the discovery of the first hidden-charm strange tetraquark with a mass of 3.98 GeV/c^2 will be addressed. The resonance was observed in the analysis of data collected at five center-of-mass energy points in the range [4.628, 4.698] GeV, with a total integrated luminosity of 3.7 fb-1. Due to its properties, the Zcs(3985) is a strong candidate for the predicted open-strange charmonium-like tetraquark with the minimal structure ccbar subar.
