  We investigate a spin-$\frac{1}{2}$ antiferromagnet, CuBr$_2$, which has
quasi-one-dimensional structural motifs. The system has previously been
observed to exhibit unusual Raman modes possibly due to a locally deformed
crystal structure driven by the low-dimensional magnetism. Using hard X-ray
scattering and neutron total scattering, here we aim to verify a specific form
of tetramerized lattice deformation proposed in the previous study. Apart from
diffuse scattering signals which we can reproduce by performing a thorough
modeling of the lattice's thermal vibrations, we do not observe evidence for a
tetramerized lattice structure within our detection sensitivity. As a result,
it is more likely that the unusual Raman modes in CuBr$_2$ arise from classical
magnon-phonon hybridization, rather than from quantum spin-singlet-driven
lattice deformation.
