Pentaquarks P_c(4380) and P_c(4450) Discovered by LHCb Collaboration?

[Dr. Rainer W. Kühne]

The LHCb Collaboration of the Large Hadron Collider reported to have observed two pentaquarks. Pentaquarks are so far hypothetical baryons which shall consist of four quarks and one antiquark.

The two pentaquarks reported by the LHCb Collaboration are named P_c(4380) and P_c(4450). Their reported quark content is duuc cbar.
http://arxiv.org/abs/1507.03414

Previously, a pentaquark named Theta(1530) with the quark content uudd sbar has been reported
http://arxiv.org/abs/hep-ex/0301020
but it has later not been confirmed.

A model of pentaquarks has been suggested by Robert Jaffe and Frank Wilczek
http://arxiv.org/abs/hep-ph/0307341

On the basis of their model, Rainer Kühne predicted a pentaquark Xi⁻⁻(1770) with the quark content ddss ubar and a pentaquark Xi⁺(1770) with the quark content uuss dbar
http://arxiv.org/abs/hep-ph/0403156

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