  An observation of the anisotropy of dark matter interactions in a
direction-sensitive detector would provide decisive evidence for the discovery
of galactic dark matter. Directional information would also provide a crucial
input to understanding its distribution in the local Universe. Most of the
existing directional dark matter detectors utilize particle tracking methods in
a low-pressure gas time projection chamber. These low pressure detectors
require excessively large volumes in order to be competitive in the search for
physics beyond the current limit. In order to avoid these volume limitations,
we consider a novel proposal, which exploits a columnar recombination effect in
a high-pressure gas time projection chamber. The ratio of scintillation to
ionization signals observed in the detector carries the angular information of
the particle interactions. In this paper, we investigate the sensitivity of a
future directional detector focused on the proposed high-pressure Xenon gas
time projection chamber. We study the prospect of detecting an anisotropy in
the dark matter velocity distribution. We find that tens of events are needed
to exclude an isotropic distribution of dark matter interactions at 95%
confidence level in the most optimistic case with head-to-tail information.
However, one needs at least 10-20 times more events without head-to-tail
information for light dark matter below 50 GeV. For an intermediate mass range,
we find it challenging to observe an anisotropy of the dark matter
distribution. Our results also show that the directional information
significantly improves precision measurements of dark matter mass and the
elastic scattering cross section for a heavy dark matter.
