Probing scotogenic effects in Higgs boson decays

Abstract

The recent observation of a Higgs boson at the LHC and experimental confirmation of the nonvanishing neutrino-mixing parameter $\mathrm{sin}{\ensuremath{\theta}}_{13}$ offer important means to test physics beyond the standard model. We explore this within the context of the scotogenic model, in which neutrinos acquire mass radiatively via one-loop interactions with dark matter. Starting with a two-parameter neutrino-mixing matrix which is consistent with the latest neutrino-oscillation data at the one-sigma level, we derive different sets of solutions for the Yukawa couplings of the nonstandard particles in the model and use the results to consider the Higgs decays into final states involving the new particles. Assuming that the lightest one of them serves as fermionic cold dark matter, we show that such decays are allowed by various experimental and theoretical constraints to have substantial rates that are already restricted by the current LHC data. We also look at their correlations with the Higgs decays into $\ensuremath{\gamma}\ensuremath{\gamma}$ and $\ensuremath{\gamma}Z$. Upcoming LHC measurements of the Higgs boson can therefore either detect scotogenic signals or place further constraints on the model.