'Dark Radiation' (Eleonora Di Valentino)
The new measurements of the Cosmic Microwave Background (CMB) anisotropies released from the Planck collaboration, allow to place new and more stringent limits on the presence of extra relativistic species at the decoupling epoch. In this talk I will present new constraints on this "dark radiation" component parametrized by the effective neutrino number N_eff, the neutrino sound speed c_s^2 and viscosity c_eff^2, showing that the Planck data alone hints to the presence of dark radiation at 91% c.l. and at more than 95% c.l. when a HST prior on the Hubble constant is assumed. I will then discuss some possible physical candidates for dark radiation, as a sterile neutrino or an asymmetric dark sector model. The next Planck data release, expected around summer 2014, will be decisive in confirming or ruling out the dark radiation.
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Probing new physics in the dark sector with Planck (Andrea Marchini)
The recent measurements of high resolution of the anisotropies in the Cosmic Microwave Background provided by the Planck satellite have been opening a new window on the early universe. On one hand LCDM model seems to be a good benchmark model, on the other hand some tensions arise in the parameters when comparing Planck values with the results of other independent experiments. Even if the tensions might be due to systematics, it is worth to investigate if they can instead be hints for new physics in the dark sector. I will show constraints on f(R) gravity and on interacting dark matter-dark energy models and I will discuss how the tensions can be mitigated in these scenarios.