Search for GeV-Scale Sterile Neutrinos Responsible for Active Neutrino Oscillations and Baryon Asymmetry of the Universe

Figure 5

Constraints on the sterile neutrino lifetime 𝜏_𝑁 coming from the baryon asymmetry of the Universe (blue solid lines: “BAU 𝑁” refers to the normal hierarchy, “BAU 𝐼” refers to the inverted hierarchy), from the seesaw mechanism (blue solid lines: “Seesaw 𝑁” refers to normal hierarchy, “Seesaw 𝐼” refers to the inverted hierarchy) and big bang nucleosynthesis (black line: “BBN”). The allowed region of parameter space is in white. Limits from direct searches presented in Figure 4 are not outlined.