  We report on the temperature dependence of the $ZrTe_5$ electronic
properties, studied at equilibrium and out of equilibrium, by means of time and
angle resolved photoelectron spectroscopy. Our results unveil the dependence of
the electronic band structure across the Fermi energy on the sample
temperature. This finding is regarded as the dominant mechanism responsible for
the anomalous resistivity observed at T* $\sim$ 160 K along with the change of
the charge carrier character from holelike to electronlike. Having addressed
these long-lasting questions, we prove the possibility to control, at the
ultrashort time scale, both the binding energy and the quasiparticle lifetime
of the valence band. These experimental evidences pave the way for optically
controlling the thermoelectric and magnetoelectric transport properties of
$ZrTe_5$.
