  We report on the spectral analysis of the X-ray pulsar LMC X-4 in its high
state out of eclipse observed by BeppoSAX. During this observation no coherent
pulsations are detected. The primary continuum is well described by a power law
with a high energy cutoff (E_cutoff ~ E_fold ~ 18 keV). The addition of a
cyclotron absorption line at ~100 keV improves the fit significantly. The
inferred magnetic moment is 1.1 10^{31} Gauss cm^3, in agreement with the value
estimated assuming that the neutron star is at the spin equilibrium, as it has
been proposed for this source. The remaining excess at low energies can be
fitted by a Comptonization of soft photons by moderately hot electrons (kT ~0.9
keV), with an optical depth \tau ~ 16. The seed photons for this Comptonization
are consistent with black body emission from the accretion disk at the
magnetospheric radius. Another possibility is to fit the soft excess with black
body and thermal bremsstrahlung. In this case the black body would originate
from cold plasma at the magnetosphere while the bremsstrahlung component may be
produced by the strong stellar wind from the companion star, ionized by the
X-ray emission from the pulsar.
