A hidden-charm S=-1 pentaquark from the decay of Λb into J/ψηΛ states

The hidden charm pentaquark state Pc(4450) observed recently by the LHCb collaboration may be of molecular nature, as advocated by some unitary approaches that also predict pentaquark partners in the strangeness S = −1 sector. In this work we argue that a hidden-charm strange pentaquark could be seen from the decay of the Λb, just as in the case of the nonstrange Pc(4450), but looking into the J/ψηΛ decay mode and forming the invariant mass spectrum of J/ψΛ pairs. In the model presented here, which assumes a standard weak decay topology and incorporates the hadronization process and final state interaction effects, we find the J/ψηΛ final states to be populated with similar strength as the J/ψK−p states employed for the observation of the non-strange pentaquark. This makes the Λb → J/ψηΛ decay to be an interesting process to observe a possible strange partner of the Pc(4450) . We study the dependence of the J/ψΛ mass spectra on various model ingredients and on the unknown properties of the strange pentaquark.

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