Primordial production of massive relic gravitational waves from a weak modification of general relativity

The production of a stochastic background of relic gravitational waves is well known in various works in the literature, where, using the so called adiabatically-amplified zero-point fluctuations process it has been shown how the standard inflationary scenario for the early universe can in principle provide a distinctive spectrum of relic gravitational waves. In this paper, it is shown that a weak modification of General Relativity produces a third massive polarization of gravitational waves and the primordial production of this polarization is analyzed adapting the adiabatically-amplified zero-point fluctuations process at this case. esence of the mass could also have important applications in cosmology as the fact that gravitational waves can have mass could give a contribution to the dark matter of the universe. end of the paper an upper bound for these relic gravitational waves, which arises from the WMAP constrains, is also released.