Caputo, AndreaEsposito, AngeloGeoffray, EmmaPolosa, Antonio D.Sun, Sichun2020-04-112020-04-112020-04-112020-03-1010.1016/j.physletb.2020.135258https://infoscience.epfl.ch/handle/20.500.14299/168128WOS:000515091400017We consider a model of sub-GeV dark matter whose interaction with the Standard Model is mediated by a new vector boson (the dark photon) which couples kinetically to the photon. We describe the possibility of constraining such a model using a superfluid He-4 detector, by means of an effective theory for the description of the superfluid phonon. We find that such a detector could provide bounds that are competitive with other direct detection experiments only for ultralight vector mediator, in agreement with previous studies. As a byproduct we also present, for the first time, the low-energy effective field theory for the interaction between photons and phonons. (C) 2020 The Author(s). Published by Elsevier B.V.Astronomy & AstrophysicsPhysics, NuclearPhysics, Particles & FieldsAstronomy & AstrophysicsPhysicslight dark mattereffective theoryheliumphonondark photontext::journal::journal article::research article