  We investigate the impact of massive neutrinos on the distribution of matter
in the semi-non-linear regime (0.1<k<0.6 h/Mpc). We present a suite of
large-scale N-body simulations quantifying the scale dependent suppression of
the total matter power spectrum, resulting from the free-streaming of massive
neutrinos out of high-density regions. Our simulations show a power suppression
of 3.5-90 per cent at k~0.6 h/Mpc for total neutrino mass, m_nu=0.05-1.9 eV
respectively. We also discuss the precision levels that future cosmological
datasets would have to achieve in order to distinguish the normal and inverted
neutrino mass hierarchies.
