  The cross section for coherent photonuclear production of J/$\psi$ is
presented as a function of the electromagnetic dissociation (EMD) of Pb. The
measurement is performed with the ALICE detector in ultra-peripheral Pb-Pb
collisions at a centre-of-mass energy per nucleon pair of
$\sqrt{s_{\mathrm{NN}}}=5.02$ TeV. Cross sections are presented in five
different J/$\psi$ rapidity ranges within $|y|<4$, with the J/$\psi$
reconstructed via its dilepton decay channels. In some events the J/$\psi$ is
not accompanied by EMD, while other events do produce neutrons from EMD at beam
rapidities either in one or the other beam direction, or in both. The cross
sections in a given rapidity range and for different configurations of neutrons
from EMD allow for the extraction of the energy dependence of this process in
the range $17 < W_{\gamma\, \mathrm{Pb, n}} <920$ GeV, where $W_{\gamma\,
\mathrm{Pb, n}}$ is the centre-of-mass energy per nucleon of the
$\gamma\,\mathrm{Pb}$ system. This range corresponds to a Bjorken-$x$ interval
spanning about three orders of magnitude: $ 1.1\times10^{-5}<x<3.3\times
10^{-2}$. In addition to the ultra-peripheral and photonuclear cross sections,
the nuclear suppression factor is obtained. These measurements point to a
strong depletion of the gluon distribution in Pb nuclei over a broad,
previously unexplored, energy range. These results, together with previous
ALICE measurements, provide unprecedented information to probe quantum
chromodynamics at high energies.
