The newly observed Zcs(3985)- state: In vacuum and a dense medium

We report on some properties of the newly observed charged hidden-charmed open strange Zcs(3985)− state by BESIII Collaboration. Assigning the quantum numbers J P = 1+ and the quark composition ccs¯ u¯ and considering it as the strange partner of the famous Zc(3900) state, we estimate the mass of the Zcs(3985)− resonance in vacuum and compare it with the experimental data. We also investigate its mass, current coupling and vector-self energy in a medium with finite density. Our result on the mass in vacuum agrees well with the experimental data. We estimate the mass and current coupling of the b-partner of this state, Zbs, in the vacuum as well. For its mass we get mZbs = 10732+97 −46 MeV, which may be checked via other nonperturbative approaches as well as future experiments. We present the dependence of the spectroscopic parameters of Zcs(3985)− state on density and observe that these parameters are linearly changed with increasing in the density.