Rare Lepton-Number-Violating $W$ Decays at the LHC: CP Violation

Some models of leptogenesis involve a nearly-degenerate pair of heavy Majorana neutrinos $N_{1,2}$ whose masses can be small, $O({rm GeV})$. There can be heavy-light neutrino mixing parametrized by $|B_{ell N}|^2 = 10^{-5}$, which leads to the rare lepton-number-violating decay $W^pm to ell_1^pm ell_2^pm (q{bar q})^mp$. With contributions to this decay from both $N_1$ and $N_2$, a CP-violating rate difference between the decay and its CP-conjugate can be generated. In this talk, I describe the prospects for measuring such a CP asymmetry $A_{rm CP}$ at the LHC. I consider thre