  n scalar-tensor theories of gravity with torsion, the gravitational field is
described in terms of a symmetric metric tensor $g$, a metric-compatible
connection $\nabla$ with torsion, and a scalar field $\phi$. The main aim is to
explore an interaction of a charged perfect fluid and a scalar field $\phi$ in
a background electromagnetic and gravitational field described by \{$g$,
$\nabla$, $\phi$\}. The interaction is based on an action functional $S_C$ of a
charged perfect fluid that is invariant under global conformal rescalings.
Using a variational principle, we obtain equations of motion for the charged
perfect fluid. Moreover, we verify that these equations of motion are
equivalent to the gauge identities obtained from the invariance of an action
functional under spacetime dffeomorphisms and a local U(1) gauge group.
