Search for GeV-Scale Sterile Neutrinos Responsible for Active Neutrino Oscillations and Baryon Asymmetry of the Universe
Figure 4
The allowed region of parameters of sterile neutrinos, responsible for neutrino oscillations (region above the dotted “seesaw” line) and for baryo/leptogenesis (region between two black solid lines). Sterile neutrinos with the parameters in the shaded region to the left of the “BBN” line would spoil predictions of primordial nucleosynthesis. Accelerator experiments, searching for heavy neutral leptons exclude regions above green lines. (a) restrictions for normal hierarchy (b) inverted hierarchy. Adopted from [27]. The region above the red curve can be probed with a single section of the detector of length m, height 5 m and width m, placed at a distance of about hundred meters, see the text for details.
