  We examine the degree of energy equipartition in 9 Galactic globular clusters
using proper motions measured with the Hubble Space Telescope. For most
clusters in the sample, this is the first energy equipartition study ever
performed. This study is also the largest of its kind, albeit with only 9
clusters. We begin by rigorously cleaning the catalogues to remove poor-quality
measurements and to ensure high signal-to-noise for the study. Using the
cleaned catalogues, we investigate how velocity dispersion $\sigma$ changes
with stellar mass $m$. We fit two functional forms: the first, a classic
power-law of the form $\sigma \propto m^{-\eta}$ where $\eta$ is the degree of
energy equipartition, and the second from Bianchini et al. (2016) parameterised
by an equipartition mass $m_{eq}$ where $\eta$ changes with stellar mass. We
find that both functions fit well but cannot distinguish with statistical
significance which function provides the best fit. All clusters exhibit varying
degrees of partial equipartition; no cluster is at or near full equipartition.
We search for correlations of $\eta$ and $m_{eq}$ with various cluster
properties. The most significant correlation is observed with the number of
core or median relaxation times ($N_{core}$ or $N_{half}$) the cluster has
experienced. Finally, we determine the radial equipartition profile for each
cluster, that is, how the degree of equipartition changes with projected
distance from the cluster centre. We do not detect statistically significant
trends in the degree of equipartition with radius. Overall, our observational
findings are in broad agreement with theoretical predictions from N-body models
published in recent years.
