  The mass spectrum of hidden charm pentaquark states composed of two diquarks
and an antiquark are calculated by use of an effective Hamiltonian which
includes explicitly the spin, color, and flavor dependent interactions. The
results show that the $P_c(4312)^+$ and $P_c(4440)^+$ states could be explained
as hidden charm pentaquark states with isospin and spin-parity
$IJ^P=1/2\left(3/2^-\right)$, the $P_c(4457)^+$ state could be explained as a
hidden charm pentaquark state with $IJ^P=1/2\left(5/2^-\right)$, and the
$P_{cs}(4459)^+$ state could be explained as a hidden charm pentaquark state
with $IJ^P=0\left(1/2^-\right)$ or $0\left(3/2^-\right)$. Predications for the
masses of other possible pentaquark states are also given, and the possible
decay channels of these hidden charm pentaquark states are discussed.
