  The formation of the Earth remains an epoch with mysterious puzzles extending
to our still incomplete understanding of the planet's potential origin and bulk
composition. Direct confirmation of the Earth's internal heat engine was
accomplished by the successful observation of geoneutrinos originating from
uranium (U) and thorium (Th) progenies, manifestations of the planet's natural
radioactivity dominated by potassium (40K) and the decay chains of uranium
(238U) and thorium (232Th). This radiogenic energy output is critical to
planetary dynamics and must be accurately measured for a complete understanding
of the overall heat budget and thermal history of the Earth. Detecting
geoneutrinos remains the only direct probe to do so and constitutes a
challenging objective in modern neutrino physics. In particular, the intriguing
potassium geoneutrinos have never been observed and thus far have been
considered impractical to measure. We propose here a novel approach for
potassium geoneutrino detection using the unique antimatter signature of
antineutrinos to reduce the otherwise overwhelming backgrounds to observing
this rarest signal. The proposed detection framework relies on the innovative
LiquidO detection technique to enable positron (e+) identification and
antineutrino interactions with ideal isotope targets identified here for the
first time. We also provide the complete experimental methodology to yield the
first potassium geoneutrino discovery.
