The Origin of Matter in the Universe

Paul Dirac proposed the baryon symmetric universe in 1933. This proposal has become very attractive now, since it seems that all pre-existing asymmetry would have been diluted if we had an inflationary stage in the early universe. However, if our universe began baryon symmetric, the tiny imbalance in numbers of baryons and anti-baryons must have been generated by some physical processes in the early universe, otherwise we would not have existed. In my talk I will show why the small neutrino mass is key to solving this long-standing problem in our understanding of the observed universe.