Double strangeness pentaquarks and other exotic hadrons in the $Ξ_b \to Ξ J/Ψ ϕ$ decay
We study the possibility that four $Ξ$ resonances $(Ξ(1620)$, $Ξ(1690)$, $Ξ(1820)$, $Ξ(1950))$ could correspond to pentaquark states, in the form of meson-baryon bound systems. We also explore the possible existence of doubly strange pentaquarks with hidden charm $(P_{css})$ and find two candidates structured in a similar form, at energies of $4493~{\rm MeV}$ and $4630~{\rm MeV}$. The meson-baryon interaction is built from t-channel meson exchange processes which are evaluated using effective Lagrangians. Moreover we analyse the $Ξ_b\toΞ~J/ψ~ϕ$ decay process, which permits exploring the existence of the heavy double strange pentaquark, as well as other exotic hadrons, in the three different two-body invariant mass spectra of the emitted particles. In the $J/ψϕ$ mass spectrum, we analyse the nature of the $X(4140)$ and $X(4160)$ resonances. In the $J/ψΞ$ invariant mass spectrum, we study the signal produced by the doubly strange pentaquark, where we conclude that it has a good chance to be detected in this reaction if its mass is around $4580-4680~{\rm MeV}$. Finally, in the $ϕΞ$ spectrum we study the likelihood to detect the $Ξ(2500)$ state.