  We analyze the two-orbital Hubbard model by means of the Composite Operator
Method with the aim at studying the phenomenon of orbital selective Mott
transition (OSMT). The model contains an interorbital interaction $U'$, in
addition to the usual intraorbital one $U$. As warming-up approximation, we use
a basis of two operators only, the Hubbard operators. The analysis of the
density of states at the chemical potential as a function of the ratio between
the bandwidths of the two orbitals shows the clear signature of an orbital
selective Mott transition as expected.
