  Inelastic x-ray scattering (IXS) was used to study the Cu-O bond-stretching
vibrations in the static stripe phase compound La1.48Nd0.4Sr0.12CuO4. It was
found that the intrinsic width in Q-space of the previously reported huge
anomalous phonon softening and broadening is approximately 0.08r.l.u HWHM. A
detailed comparison was also made to inelastic neutron scattering (INS)
studies, which indicate a two-peak lineshape (with superimposed broad and
narrow peaks) in the vicinity of the anomaly. The high resolution IXS data show
that the narrow peak is mostly an artifact of the poor transverse Q-resolution
of INS. Otherwise the agreement between the INS and IXS was excellent.
