  In a previous work we have studied the isospin 1/2 lowest positive and
negative parity states of the pentaquark $uudc\overline{c}$, in a constituent
quark model with a linear confinement and an SU(4) flavor-spin hyperfine
interaction and we compared the results with the $P^+_c(4312)$, $P^+_c(4440)$
and $P^+_c(4457)$ pentaquarks observed at LHCb in 2019. Here we extend the
previous work by calculating ratios of decay rates of the $P_c$ pentaquarks to
$J/\Psi$ and $\eta_c$ and similarly the ratio of decay rates to $\Lambda_c
{\bar D}^*$ and $\Lambda_c \bar D$. Our predictions are based on the
SU(4)$\times$SU(2) structure of compact pentaquarks.
