Study on $Z_{cs}$ and excited $B_s^0$ states in the chiral quark model

Abstract

Stimulated by the newly observed charged hidden-charm state $Z_{cs}(3985{)}^{-}$ by BESIII Collaboration, $Z_{cs}(4000{)}^{+}$, $Z_{cs}(4220{)}^{+}$ and the excited $B_s^0$ states by LHCb Collaboration, a full calculation including masses and decay widths is emerged in the chiral quark model. For $Z_{cs}$ states, we assign quantum numbers $I(J^P)=\frac{1}{2}(1^{+})$ and quark composition $c\bar{c}s\bar{u}$ according to the experiment. For $B_s^0$ states, systematically investigations are performed with $I(J^P)=0(0^{+}),0(1^{+}),0(2^{+})$ both in 2-body $b\bar{s}$ and 4-body $b\bar{s}q\bar{q}(q=u\mathrm{or}\mathrm{d})$ systems. Each tetraquark calculation takes all structures including meson-meson, diquark-antidiquark and all possible color configurations into account. Among the numerical techniques to solve the 2-body and 4-body Schr{ö}dinger equation, the spatial wave functions are expanded in series of Gaussian basis functions for high precision, which is the way Gaussian expansion method so called. Our results indicate that the low-lying states of 4-quark system are all higher than the corresponding thresholds either for $c\bar{c}s\bar{u}$ or for $b\bar{s}q\bar{q}$ systems. With the help of the real scaling method, we found two resonance states with masses of 4023 MeV and 4042 MeV for $c\bar{c}s\bar{u}$ system. The state $c\bar{c}s\bar{u}(4042)$ has a consistent mass and decay width with the recent observed state $Z_{cs}(3985{)}^{-}$. For $b\bar{s}q\bar{q}$ system with $J=0$, some resonance states are also found. The newly observed excited $B_s^0$ states can be accommodated in the chiral quark model as $2S$ or $1D$ states, and the mixing with four-quark states are also needed to be considered.

9 pages,10 figures

References in corpus (11)

• Observation of a near-threshold structure in the $K^{+}$ recoil-mass spectra in $e^{+}{e}^{-}\to K^{+}(D_s^{-}{D}^{\ast 0}+D_s^{\ast -}{D}^0)$
• Observation of new resonances decaying to $D\pi$ and $D^{\ast }\pi$ in inclusive $e^{+}{e}^{-}$ collisions near $\sqrt{s}=$10.58 GeV
• $B$ and $B_s$ Meson Spectroscopy
• Excited bottom and bottom-strange mesons in the quark model
• $Z_{cs}(3985{)}^{-}$ as the $U$-spin partner of $Z_c(3900{)}^{-}$ and implication of other states in the ${\text{SU(3)}}_F$ symmetry and heavy quark symmetry
• Strong decays of higher excited heavy-light mesons in a chiral quark model
• Decoding the nature of $Z_{cs}(3985)$ and establishing the spectrum of charged heavy quarkoniumlike states in chiral effective field theory
• $Z_{cs}(3985{)}^{-}$: a strange hidden-charm tetraquark resonance or not?
• The strange partner of the $Z_c$ structures in a coupled-channels model
• Spectrum of Higher excitations of $B$ and $D$ mesons in the relativistic potential model
• The newly observed $Z_{cs}(3985{)}^{-}$ state: in vacuum and a dense medium

Cited by in corpus (12)

• An updated review of the new hadron states
• Implications of the $Z_{cs}(3985)$ and $Z_{cs}(4000)$ as two different states
• Hidden-charm tetraquarks with strangeness in the chiral quark model
• Is $Z_{cs}(3982)$ a molecular partner of $Z_c(3900)$ and $Z_c(4020)$ states?
• Doubly heavy tetraquark states $cc\bar{u}\bar{d}$ and $bb\bar{u}\bar{d}$
• $Z_{cs}$ states from the $D_s^{\ast }{\bar{D}}^{\ast }$ and $J/\psi K^{\ast }$ coupled channels: Signal in $B^{+}\to J/\psi \varphi K^{+}$ decay
• $Z_{cs}(3985)$ in next-to-leading-order chiral effective field theory -- the first truncation uncertainty analysis
• The assignments of the $B_s$ mesons within the screened potential model and ${}^3{P}_0$ model
• Search for hidden-charm tetraquark with strangeness in $e^{+}{e}^{-}\to K^{+}{D}_s^{\ast -}{D}^{\ast 0}+c.c.$
• The $Z_{cs}$ states and the mixture of hadronic molecule and diquark-anti-diquark components within effective field theory
• Hunting for the heavy quark spin symmetry partner of $Z_{cs}$
• Spectrum of Hidden-Charm, Open-Strange Exotics in the Dynamical Diquark Model