  A Weyl semimetal is a new type of topological quantum phase with intriguing
physics near the Weyl nodes. Although the equilibrium state of Weyl semimetals
has been investigated, the ultrafast dynamics near the Weyl node in the
nonequilibrium state is still missing. Here by performing time and angle
resolved photoemission spectroscopy on type-II Weyl semimetal MoTe$_2$, we
reveal the dispersion of the unoccupied states and identify the Weyl node at 70
meV above E$_F$. Moreover, by tracking the ultrafast relaxation dynamics near
the Weyl node upon photo-excitation with energy, momentum and temporal
resolution, two intrinsic recovery timescales are observed, a fast one of 430
fs and a slow one of 4.1 ps, which are associated with hot electron cooling by
optical phonon cascade emission and anharmonic decay of hot optical phonons
respectively. The electron population shows a metallic response, and the two
temperature model fitting of the transient electronic temperature gives an
electron-phonon coupling constant of $\lambda\langle\Omega^2\rangle\simeq32$
$\textrm{meV}^2$. Our work provides important dynamic information for
understanding the relaxation mechanism of a Weyl semimetal and for exploiting
potential applications using ultrafast optical control.
