Hi, just as an introduction, my amateur knowledge in particle physics reaches to the Standard Model (just to put a number, 70 or 80 percent of its mathematical content understood) and then I understand the basic problems of physics beyond SM in a conceptual but not mathematical way. So Ive been starting to read some papers (example Sterile Neutrinos White Paper). Some of my biggest holes are in things related to renormalization group and, as a consequence, I have some conceptual doubts: 1) Here it says that sterile neutrinos can solve lots of problems like DM, matter-antimatter asymmetry and such, and it says that their masses in order to be natural should be no more than some value. What is natural in this model? Those masses? Every parameter? (in other words, the unnatural Higgs mass issue is solved with this model?) 2) Asymptotic Safety and Higgs Boson Mass Is it another way to solve the unnaturalness problem of the Higgs mass? Sorry for my English, for my gaps, thanks for your answers, and for all of you that didn't know these papers, well here you have them, seems very promising.