It seems to me that spin is important in LENR because spin somehow
correlates with mass. The key to the LENR reaction is the production of
additional mass of the quarks that comprise hadrons. This change in quark
mass is induced by unbalanced magnetic field lines. This type of
anisometric field lines produces an increase in the spin rate of the quark
which will add energy to the quark. Balanced magnetic field lines do not
increase the spin of the quark. When the quantum of additional spin energy
is reached, the quark will convert that spin energy into additional mass.
When mass is added to a quark, the flavor of the quark changes and the
quark will jump to the next higher flavor. For protons and neutrons in an
anisotropic magnetic field, the up or down quark will transform into a
strange quark, the flavor that is the next up in energy/mass size. This
change in quark flavor will convert a proton to other subatomic particles
that end up as kaons.
Actually, things get more complicated. The lambda is a baryon
is made up of three quarks: an up, a down and a strange quark. Based on the
amount of magnetic energy that is pumped into the proton or the neutron,
however, a variety of different Lamba particles can be produced. The third
converted quark might be strange, charm, beauty, bottom, or top. This
Lambda particle will decay in short order to produce a zoo of different
decay particle types including the kaon.
And then thing get even more complicated when subatomic molecules form.