It
is certain that the origin of chiral excess must have arrived
very early in the chemistry leading to the origin of life. Either
chiral excess was initiated by one of the four universal forces or
it was a result of a statistical thermodynamic fluctuation in the
confines of the electromagnetic force involving a second law violation,
followed by an unlikely amplification. Only the weak force expresses
parity violation, arising from weak neutral currents, as a force of
nature. For over 5 decades, weak-force parity violation’s role
in the biomolecular selection, and consequently in homochirality,
remains significant and beyond possible exclusion. Yamagata originally
proposed that weak neutral currents interacting with Earth’s
natural racemic materials lead to terrestrial homochirality. However,
a number of authors have shown that the energy available in the electroweak
field is insufficient to generate a chiral excess on Earth, even with
a significant autocatalytic amplification process. Here, we revive
the most important aspect of the hypothesis that the weak force is
the origin of homochirality but caveat that the phenomena originally
took place far from Earth via neutrino–electron interactions.
Neutrinos exhibit chirality; only left-handed neutrinos interact with
the weak force. Neutrino chirality can be quantum mechanically described
by either right- or left-handed wave functions, Ψ(R) or Ψ(L). Unlike electrons, neutrinos travel near
the speed of light, very rarely interact with matter, and are born
only with left-handed chirality (Ψ(ν,L)). Conversely,
antineutrinos only have right-handed chirality. Left-handed neutrinos
interact preferentially with like-handed fermions (e.g., left-handed
translating electrons). The unpaired electron in a stationary chiral
radical transmits spin density into the chiral structure and is thus
itself chiral. Consequently, when polarized (in either the “up”
or “down” spin state) by a strong B-field, its chirality (Ψ(ρ,R) or Ψ(ρ,L)) is locked in place. The left-handed neutrinos
interact preferentially with chiral radicals (via the weak-force Hamiltonian, H
w) that have a complementary left-handed chirality:
⟨Ψ(ρ,L)|H
w|Ψ(ν,L)⟩ is greater than ⟨Ψ(ρ,R)|H
w|Ψ(ν,L)
⟩. In areas where there exist a very large
neutrino (ν) flux and a very large B-field,
as in the vicinity of a collapsing white dwarf, parity-violating neutrino-free
radical reactions lead to an enantiomeric excess. The neutrino–electron
scattering is mediated by the Zo boson, wherein the handedness
of the neutrino leads to preferential interactions with one of the
radical enantiomers: stereoselective neutrino unpaired electron ejection.
This is consistent with predictions of Senami and Ito who have pointed
out that, in space, one of an enantiomeric pair can be selectively
destroyed by interactions with astronomical particles, such as neutrinos.
As in the case of Hazen’s ur-minerals, hyperbolic ejection
exports the weak force-generated ur-enantiomers upon the rest of the
cosmos.