Threshold effects as the origin of $Z_{cs}(4000)$, $Z_{cs}(4220)$ and $X(4700)$ observed in $B^{+}\to J/\psi \varphi K^{+}$

Abstract

We investigate the $B^{+}\to J/\psi \varphi K^{+}$ decay via various rescattering diagrams. Without introducing genuine exotic resonances, it is shown that the $Z_{cs}(4000)$, $Z_{cs}(4220)$ and $X(4700)$ reported by the LHCb collaboration can be simulated by the $J/\psi K^{\ast +}$, ${\psi }^{\prime }{K}^{+}$ and ${\psi }^{\prime }\varphi$ threshold cusps, respectively. These cusps are enhanced by some nearby triangle singularities. The $X(4685)$ with $J^P=1^{+}$ cannot be well simulated by the threshold effects in our model, which implies that it may be a genuine resonance.

Comments: 7 pages, 6 figures, 2 tables