Pentaquarks and resonances in the $pJ/ψ$ spectrum

Abstract

We consider exotic baryons with hidden charm as antiquark-diquark-diquark composite systems. Spin and isospin structure of such exotic states is given and masses are estimated. The data for production of pentaquarks in the reaction $Λ_b\to K^-p J/ψ$ are discussed. We suggest that the narrow peak in $pJ/ψ$ spectra at 4450 MeV is antiquark-diquark-diquark state with negative parity, $5/2^{-}(4450)$, while the broad bump $3/2^{+}(4380)$ is the result of rescatterings in the ($pJ/ψ$)-channel. Positions of other pentaquarks with negative parity are estimated.

5 pages