Weak Gravitational Lensing of the Cosmic Microwave Background Radiation

The ACBAR collaboration claimed at the beginning of the last year a detection of a weak gravitational lensing signal at more than 3 standard deviations, based only on the smoothing of the acoustic oscillations in the Cosmic Microwave Background (hereafter CMB) anisotropies power spectrum. In order to reproduce and to study the ACBAR result I introduce a new parameter AL that scales the lensing potential such as: AL=0 corresponds to the unlensed model while AL=1 is the expected lensed scenario in the standard ΛCDM model. Here I present the constraints obtained on this new lensing parameter analysing several datasets of CMB temperature and polarization anisotropies.