Effective theory for baryogenesis with a Majorana fermion pair coupled to quarks

With a goal toward explaining the observed baryon asymmetry of Universe, we extend standard model (SM) by adding vector-vector dimension-six effective operator coupling new Dirac fermion $\ensuremath{\chi}$, uncharged under SM gauge symmetries but charged number, to quarklike up-type and two identical down-type fermions. We introduce number violation Majorana masses which splits into fermions with unequal masses. speculate on origin operator, mass, physics sector connection considering some ultraviolet completion examples. In addition violation, show that $C$ $CP$ invariances can be violated in theory, interference between tree loop amplitudes on-shell intermediate states lead $\ensuremath{\chi}$ decay scattering processes. provide numerical estimates for generated, neutron-antineutron oscillation rate.