Majorana fermions and CP-invariance of chiral gauge theories on the lattice

Understand

The construction of massless Majorana fermions with chiral Yukawa couplings on the lattice is considered.

• We find topological obstructions tightly linked to those underlying the Nielsen-Ninomiya no-go theorem.
• In contradistinction to chiral fermions the obstructions originate only from the combination of the Dirac action and the Yukawa term.
• These findings are used to construct a chirally invariant lattice action.