  By means of pump-probe time- and angle-resolved photoelectron spectroscopy,
we provide evidence of a sizeable reduction of the Fermi velocity of
out-of-equilibrium Dirac bands in the quasi-two-dimensional semimetal
BaNiS$_2$. First-principle calculations indicate that this band renormalization
is ascribed to a change in non-local electron correlations driven by a
photo-induced enhancement of screening properties. This effect is accompanied
by a slowing down of the Dirac fermions and by a non-rigid shift of the bands
at the center of the Brillouin zone. This result suggests that other similar
electronic structure renormalizations may be photoinduced in other materials in
presence of strong non-local correlations.
