Eur. Phys. J. C (2021) 81: 854
https://doi.org/10.1140/epjc/s10052-021-09590-y

Regular Article - Theoretical Physics

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

Center for Joint Quantum Studies and Department of Physics, School of Science, Tianjin University, 300350, Tianjin, China

^b xiaohai.liu@tju.edu.cn

Received: 28 May 2021
Accepted: 28 August 2021
Published online: 28 September 2021

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 $Z_{\mathit{cs}}(4000)$, $Z_{\mathit{cs}}(4220)$ 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.