  We present a measurement of the low-mass quiescent size-mass relation at
Cosmic Noon (1<z<3) from the JWST PRIMER and UNCOVER treasury surveys, which
highlights two distinct classes of quiescent galaxies. While the massive
population is well studied at these redshifts, the low-mass end has been
previously under-explored due to a lack of observing facilities with sufficient
sensitivity and spatial resolution. We select a conservative sample of low-mass
quiescent galaxy candidates using rest-frame UVJ colors and specific star
formation rate criteria and measure galaxy morphology in both rest-frame
UV/optical wavelengths (F150W) and rest-frame near-infrared (F444W). We confirm
an unambiguous flattening of the low-mass quiescent size-mass relation, which
results from the separation of the quiescent galaxy sample into two distinct
populations at $\log(M_\star/M_\odot)\sim10.3$: low-mass quiescent galaxies
that are notably younger and have disky structures, and massive galaxies
consistent with spheroidal morphologies and older median stellar ages. These
separate populations imply mass quenching dominates at the massive end while
other mechanisms, such as environmental or feedback-driven quenching, form the
low-mass end. This stellar mass dependent slope of the quiescent size-mass
relation could also indicate a shift from size growth due to star formation
(low masses) to growth via mergers (massive galaxies). The transition mass
between these two populations also corresponds with other dramatic changes and
characteristic masses in several galaxy evolution scaling relations (e.g.
star-formation efficiency, dust obscuration, and stellar-halo mass ratios),
further highlighting the stark dichotomy between low-mass and massive galaxy
formation.
