Description
In this talk We will discuss the effects that a modified sector tensor
can produce on the polarisation CMB power spectra. Alternative theories
of gravity can give the graviton a mass but also modify the dispersion
relation of the gravitational waves. by A mass for the graviton can
affect the large angular scales and in general a modified dispersion
relation could change the position of the acoustic peaks. These effect
modifies either the CMB power spectrum and bispectrum, with respect to
the canonical case. Thus given the precision of the CMB experiments, if
detected, primordial gravitational waves can help to constraint gravity
at a much higher accuracy.