  We investigate the idea of detecting pure neutrino-hydrogen interactions in a
multinuclear target using the transverse kinematic imbalance technique [Lu et
al., Phys. Rev. D 92, 051302 (2015)] in a high-pressure time projection chamber
(HPTPC). With full solid-angle acceptance, MeV-level proton tracking threshold,
state-of-the-art tracking resolution, and an O(100 m^3) gas volume at 10 bar,
an HPTPC could provide an opportunity to realize this technique. We propose the
use of hydrogen-rich gases in the TPC to achieve high detection purity with
large hydrogen mass. With the projected neutrino beam exposure at the DUNE
experiment, neutrino-hydrogen events of the order of 10^4 per year with purity
above 90% could be achieved with such an HPTPC using methane gas. In this
paper, we present a systematic study of the event rate and purity for a variety
of argon-alkane mixtures, and examine these gas candidates for the TPC
tracking-related properties.
