The spectral energy density of the relic gravitons in the context of the ΛCDM model evaluated at the Ligo/Virgo frequency as a function of the tensor-to-scalar ratio. In the plot at the right the spectral index does not run (see Eq. (1.5)) while in the left plot the spectral index does run and it is given by Eq. (1.6). To guide the intuition consider that (advanced) wide-band interferometers will achieve, optimistically, a sensitivity of 10-10 in ΩGW(ν, τ0). Taking into account the current bounds on rT (see Tabs. 1 and 2) it is clear that the ΛCDM scenario is definitively too small to provide a serious target for wide-band detectors.