Response of the common mode of interferometric detectors to a stochastic   background of massive scalar radiation
  We compute the angular pattern and the overlap reduction functions for the geodesic and non-geodesic response of the common mode of two interferometers interacting with a stochastic, massive scalar background. We also discuss the possible overlap between common and differential modes. We find that the cross-correlated response of two common modes to a non-relativistic background may be higher than the response of two differential modes to the same background. 
N. Bonasia and M. Gasperini