  The self-consistent Born approximation quantitatively fails to capture
disorder effects in semimetals. We present an alternative, simple-to-use
non-perturbative approach to calculate the disorder induced self-energy. It
requires a sufficient broadening of the quasiparticle pole and the solution of
a differential equation on the imaginary frequency axis. We demonstrate the
performance of our method for various paradigmatic semimetal Hamiltonians and
compare our results to exact numerical reference data. For intermediate and
strong disorder, our approach yields quantitatively correct momentum resolved
results. It is thus complementary to existing RG treatments of weak disorder in
semimetals.
