  Despite recent progress, the astrophysical channels responsible for rapid
neutron capture (r-process) nucleosynthesis remain an unsettled question.
Observations of kilonovae following gravitational wave-detected neutron star
mergers established mergers as one site of the r-process, but additional
sources may be needed to fully explain r-process enrichment in the Universe.
One intriguing possibility is that rapidly rotating massive stars undergoing
core collapse launch r-process-rich outflows off the accretion disks formed
from their infalling matter. In this scenario, r-process winds comprise one
component of the supernova (SN) ejecta produced by "collapsar" explosions. We
present the first systematic study of the effects of r-process enrichment on
the emission from collapsar-generated SNe. We semi-analytically model r-process
SN emission from explosion out to late times, and determine its distinguishing
features. The ease with which r-process SNe can be identified depends on how
effectively wind material mixes into the initially r-process-free outer layers
of the ejecta. In many cases, enrichment produces a near infrared (NIR) excess
that can be detected within ~75 days of explosion. We also discuss optimal
targets and observing strategies for testing the r-process collapsar theory,
and find that frequent monitoring of optical and NIR emission from
high-velocity SNe in the first few months after explosion offers a reasonable
chance of success while respecting finite observing resources. Such early
identification of r-process collapsar candidates also lays the foundation for
nebular-phase spectroscopic follow-up in the near- and mid-infrared, for
example with the James Webb Space Telescope.
