  QCD at finite densities of heavy quarks is investigated using the
density-of-states method. The phase factor expectation value of the quark
determinant is calculated to unprecedented precision as a function of the
chemical potential. Results are validated using those from a reweighting
approach where the latter can produce a significant signal-to-noise ratio. We
confirm the particle-hole symmetry at low temperatures, find a strong sign
problem at intermediate values of the chemical potential, and an inverse Silver
Blaze feature for chemical potentials close to the onset value: here, the phase
quenched theory underestimates the density of the full theory.
