MICROSCOPE Mission: first constraints on the violation of the weak equivalence principle by a light scalar dilaton

Joel Bergé (1) , Philippe Brax (2) , Gilles Métris (3) , Martin Pernot-Borràs (4, 1) , Pierre Touboul (1) , Jean-Philippe Uzan (4, 5)

1 DPHY, ONERA, Université Paris Saclay (COmUE) [Châtillon]
2 IPHT - Institut de Physique Théorique - UMR CNRS 3681
3 OCA - Observatoire de la Côte d'Azur
4 IAP - Institut d'Astrophysique de Paris
5 Institut Lagrange de Paris

The existence of a light or massive scalar field with a coupling to matter weaker than gravitational strength is a possible source of violation of the weak equivalence principle. We use the first results on the Eötvös parameter by the MICROSCOPE experiment to set new constraints on such scalar fields. For a massive scalar field of mass smaller than 10$^{−12}$ eV (i.e. range larger than a few 10$^5$ m) we improve existing constraints by one order of magnitude to |$\alpha$| < 10$^{−11}$ if the scalar field couples to the baryon number and to |$\alpha$| < 10$^{−12}$ if the scalar field couples to the difference between the baryon and the lepton numbers. We also consider a model describing the coupling of a generic dilaton to the standard matter fields with five parameters, for a light field: we find that for masses smaller than 10$^{−12}$ eV, the constraints on the dilaton coupling parameters are improved by one order of magnitude compared to previous equivalence principle tests.

Mots clés: Experimental test of gravitational theories; Experimental test of gravitational theories

Domaines: Physique [physics]

Joel Bergé, Philippe Brax, Gilles Métris, Martin Pernot-Borràs, Pierre Touboul, et al.. MICROSCOPE Mission: first constraints on the violation of the weak equivalence principle by a light scalar dilaton. Physical Review Letters, 2018, 120, pp.141101. ⟨10.1103/PhysRevLett.120.141101⟩. ⟨cea-01686662v2⟩