  We study the interplay of interactions and topology in a pseudo-spin Weyl
system, obtained from a minimally modified Hubbard model, using the numerically
exact auxiliary-field quantum Monte Carlo method complemented by mean-field
theory. We find that the pseudo-spin plays a key role in the pairing mechanism,
and its effect is reflected in the structure of the pairing amplitude. An
attractive on-site interaction leads to pairing between quasiparticles carrying
opposite spin and opposite topological charge, resulting in the formation of
real-spin singlet pairs that are a mixture of pseudo-spin singlet and
pseudo-spin triplet. Our results provide a detailed characterization of the
exotic pairing behavior in this system, and represent an important step towards
a more complete understanding of superconductivity in the context of
topological band structures, which will help guide searches for topological
superconductivity in real materials and ultracold atoms.
