Experimental study of the propagation of scintillation light in Liquid Argon

Properties of the propagation of scintillation light in liquid argon (LAr), at $\lambda$ ~128 nm wavelength, have been experimentally investigated in a dedicated setup at CERN. The speed of scintillation photons has been measured for the first time in this medium, refractive index and the Rayleigh scattering are being studied as well. Such measurement provides a key ingredient for the interpretation of data from the current and next generation large mass LAr detectors as those dedicated to the search for rare events such as neutrinos or Dark Matter. Furthermore the improvement on the understanding of the scintillation light propagation represent a benchmark for the multiple theoretical models and simulations for the next generation of detectors which are now based on still incomplete measurements and calculations.