I`ve spent some time reading about the baryon asymmetry and the Sakharov`s conditions, and there some things I didn't exactly get: 1. Interactions out of thermal equilibrium: isn't it trivial? our universe is expanding so, of course, it out of equilibrium. 2. CP violation: I`ve read that Cronin and Fitch experiment proves that issue, the problem is that the amount of the CP violation there is too small to explain the baryon asymmetry in the universe. 3. Baryon number B violation. My question is how can you solve problem 2. 3. using the lepton sector. Or more precisely by using the Majorana neutrinos in the lepton sector, making a lepton asymmetry. And how do you convert it to a baryon asymmetry using the sphaleron reactions? (An explanation about those reactions would be nice since I'm not that familiar with them). Thanks!