Abstract

Weakly interacting slim particles (WISPs) appear often in extensions of the standard model, string theory in particular. This is the case of pseudo Nambu Goldstone Bosons, stringy axions, moduli, hidden photons, mini-charged particles and a long etc. The strongest bounds on their existence come frequently from cosmology and astrophysics but, in particular cases, laboratory experiments at the low energy, high intensity frontier, are more relevant. In this talk we review the most relevant astro/cosmo arguments and laboratory experiments used to constrain the existence of WIS Ps, focusing on the most discussed cases of axion-like particles (ALPs) and Hidden Photons. We will also pay attention to the recent anomalies which could be pointing to the existence of WIS Ps: the anomalous cooling rate of white dwarfs and the transparency of the Universe to gamma-rays. Finally, we will conclude discussing WIS Ps as testable cold dark matter candidates.