title: Light scalars coupled to photons and non-newtonian forces.
abstract: A particle phi coupling to two photons couples also radiatively to charged particles, like protons. If the particle is a light scalar, this induced coupling leads to spin-independent non-Newtonian forces. We show that the experimental constraints on exotic, fifth-type forces lead to stringent constraints on the phigammagamma coupling. We discuss the impact on the recent PVLAS results and the role of paraphoton models introduced to solve the PVLAS-CAST puzzle.
authors.affiliation: INAF-IASF, Via E. Bassini 15, I-20133 Milan, Italy.
authors.forename: Arnaud
authors.initials: A
authors.lastname: Dupays
authors.forename: Eduard
authors.initials: E
authors.lastname: Massó
authors.forename: Javier
authors.initials: J
authors.lastname: Redondo
authors.forename: Carlo
authors.initials: C
authors.lastname: Rizzo