Laser interferometer response to scalar massive gravitational waves

We analyze the response of the gravitational wave detector to a scalar massive plane gravitational wave. We give the compact form of the response and discuss its angular and frequency characteristics. The derivations is carried out in the conformal and the synchronous gauges and the equivalence of the two approaches is shown. In the case of the massive Brans-Dicke theory we solve the linearized vacuum field equations in the two gauges as well.