Scalar gravitational waves and Einstein frame

The response of a gravitational wave detector to scalar waves is analysed i n the framework of the debate on the choice of conformal frames for scalar- tensor theories. A correction to the geodesic equation arising in the Einst ein conformal frame modifies the geodesic deviation equation. This modifica tion is due to the nonmetricity of the theory in the Einstein frame, yieldi ng a longitudinal mode that is absent in the Jordan conformal frame. (C) 20 01 Elsevier Science B.V. All rights reserved.