We study the decay of ${\mathrm{\Lambda }}_b\to J/\psi \mathrm{\Lambda }\varphi$ by taking into account the intermediate resonances $X(4140)$, $X(4160)$, and $P_{cs}(4459)$. In addition to the peak of the $X(4140)$, we also find a bump structure around 4160 MeV followed by a cusp structure around $D_s^{*}{\overline{D}}_s^{*}$ threshold in the $J/\psi \varphi$ invariant mass distribution of the ${\mathrm{\Lambda }}_b\to J/\psi \mathrm{\Lambda }\varphi$ process, which can be associated to the $D_s^{*}{\overline{D}}_s^{*}$ molecular state $X(4160)$. We also show that this reaction can also be used to confirm the existence of the hidden-charm pentaquark $P_{cs}(4459)$ with strangeness. We predict an enhancement structure close to the threshold in the $D_s^{*}{\overline{D}}_s^{*}$ invariant mass distribution of the ${\mathrm{\Lambda }}_b\to D_s^{*}{\overline{D}}_s^{*}\mathrm{\Lambda }$ process, which is the reflection of the $X(4160)$ and should not be misidentified with a new resonance. We strongly suggest experimentalists to further measure these processes, which can be useful to clarify the nature of $X(4140)$ and $X(4160)$ resonances, and to confirm the existence of the $P_{cs}(4459)$.

• Received 7 December 2020
• Accepted 1 February 2021

DOI:https://doi.org/10.1103/PhysRevD.103.034019

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Published by the American Physical Society