Massó i Soler, Eduard, 1954-Toldrà Sabaté, Ramon2010-05-062010-05-0619950556-2821https://hdl.handle.net/2445/12355A pseudoscalar or scalar particle $\phi$ that couples to two photons but not to leptons, quarks and nucleons would have effects in most of the experiments searching for axions, since these are based on the $a \gamma \gamma $ coupling. We examine the laboratory, astrophysical and cosmological constraints on $\phi$ and study whether it may constitute a substantial part of the dark matter. We also generalize the $\phi$ interactions to possess $SU(2) \times U(1)$ gauge invariance, and analyze the phenomenological implications.9 p.application/pdfeng(c) The American Physical Society, 1995AstronomiaAstrofísicaPartícules (Física nuclear)AstronomyAstrophysicsParticles (Nuclear physics)Dark matter (Astronomy)Matèria fosca (Astronomia)info:eu-repo/semantics/article508063info:eu-repo/semantics/openAccess