We show that even moderate excess of neutrons over protons in nuclear
matter, such as in Pb-208 can lead to large rho-omega mixing at densit
ies of the order of twice the nuclear saturation density and higher. T
he typical mixing angle is of the order of 10 degrees. The mixing may
result in noticeable shifts of the positions and widths of resonances.
We also analyze temperature effects and find that temperatures up to
50 MeV have practically no effect on the mixing. (C) 1998 Elsevier Sci
ence B.V. All rights reserved.