The paper proposes a minimal extension of the Standard Model (SM) to explain the observed small Majorana masses of left-handed neutrinos through a one-loop radiative seesaw mechanism. This model introduces two candidates for dark matter: one bosonic and one fermionic. The model is structured to be verifiable in experiments at the Large Hadron Collider (LHC). The key features include: 1. **Model Structure**: The particle content includes left-handed lepton doublets, right-handed leptons, heavy singlet Majorana neutrinos ($N_i$), and a scalar doublet $(\eta^+, \eta^0)$, all transforming under $SU(2)_L \times U(1)_Y \times Z_2$ with $Z_2$ being an exact symmetry. 2. **Yukawa Interactions**: The Yukawa interactions involve the exchange of $\eta^0$ and $\eta^+$, leading to the radiative generation of neutrino masses. 3. **Dark Matter Candidates**: The lightest stable particle (LSP) can be either a boson ($\sqrt{2} Re \eta^0$) or a fermion ($N_{1,2,3}$). Both candidates have observable decay processes that can be used to extract Yukawa couplings and verify the seesaw mechanism. 4. **Experimental Feasibility**: The seesaw scale is reduced to around 1 TeV, making it amenable to experimental verification at the LHC. 5. **Lepton Family Symmetry**: The model is flexible in incorporating lepton family symmetry, such as the tetrahedral symmetry $A_4$, which can implement tribimaximal mixing. 6. **Conclusion**: The minimal extension to the SM provides a framework for realistic radiative neutrino masses and dark matter candidates, with the potential for experimental verification in upcoming LHC experiments. This work was supported by the U.S. Department of Energy under Grant No. DEFG03-94ER40837.The paper proposes a minimal extension of the Standard Model (SM) to explain the observed small Majorana masses of left-handed neutrinos through a one-loop radiative seesaw mechanism. This model introduces two candidates for dark matter: one bosonic and one fermionic. The model is structured to be verifiable in experiments at the Large Hadron Collider (LHC). The key features include: 1. **Model Structure**: The particle content includes left-handed lepton doublets, right-handed leptons, heavy singlet Majorana neutrinos ($N_i$), and a scalar doublet $(\eta^+, \eta^0)$, all transforming under $SU(2)_L \times U(1)_Y \times Z_2$ with $Z_2$ being an exact symmetry. 2. **Yukawa Interactions**: The Yukawa interactions involve the exchange of $\eta^0$ and $\eta^+$, leading to the radiative generation of neutrino masses. 3. **Dark Matter Candidates**: The lightest stable particle (LSP) can be either a boson ($\sqrt{2} Re \eta^0$) or a fermion ($N_{1,2,3}$). Both candidates have observable decay processes that can be used to extract Yukawa couplings and verify the seesaw mechanism. 4. **Experimental Feasibility**: The seesaw scale is reduced to around 1 TeV, making it amenable to experimental verification at the LHC. 5. **Lepton Family Symmetry**: The model is flexible in incorporating lepton family symmetry, such as the tetrahedral symmetry $A_4$, which can implement tribimaximal mixing. 6. **Conclusion**: The minimal extension to the SM provides a framework for realistic radiative neutrino masses and dark matter candidates, with the potential for experimental verification in upcoming LHC experiments. This work was supported by the U.S. Department of Energy under Grant No. DEFG03-94ER40837.