  We present analysis of 4U 1626-67, a 7.7 s pulsar in a low-mass X-ray binary
system, observed with the hard X-ray detector of the Japanese X-ray satellite
Suzaku in March 2006 for a net exposure of \sim88 ks. The source was detected
at an average 10-60 keV flux of \sim4 x10^-10 erg cm^-2 s^-1. The
phase-averaged spectrum is reproduced well by combining a negative and positive
power-law times exponential cutoff (NPEX) model modified at \sim 37 keV by a
cyclotron resonance scattering feature (CRSF). The phase-resolved analysis
shows that the spectra at the bright phases are well fit by the NPEX with CRSF
model. On the other hand, the spectrum in the dim phase lacks the NPEX
high-energy cutoff component, and the CRSF can be reproduced by either an
emission or an absorption profile. When fitting the dim phase spectrum with the
NPEX plus Gaussian model, we find that the feature is better described in terms
of an emission rather than an absorption profile. The statistical significance
of this result, evaluated by means of an F-test, is between 2.91 x 10^-3 and
1.53 x 10^-5, taking into account the systematic errors in the background
evaluation of HXD-PIN. We find that, the emission profile is more feasible than
the absorption one for comparing the physical parameters in other phases.
Therefore, we have possibly detected an emission line at the cyclotron
resonance energy in the dim phase.
