A view of neutrino studies with the next generation facilities

Abstract

Neutrino physics is nowadays receiving more and more attention as a possible source of information for the long-standing investigation of new physics beyond the Standard Model. The rather recent measurement of the third mixing angle θ₁₃ in the standard mixing oscillation scenario encourages the pursuit of what is still missing: the size of any leptonic CP violation, absolute neutrino masses and the characteristic nature of the neutrino. Several projects are currently running and they are providing impressive results. In this review, the phenomenology of neutrino oscillations that results from the last two decades of investigations is reviewed, with emphasis on our current knowledge and on what lesson can be taken from the past. We then present a critical discussion of current studies on the mass ordering and what might be expected from future results. Our conclusion is that decisions determining the next generation of experiments and investigations have to be strictly based on the findings of the current generation of experiment. In this sense it would be wise to wait a few years before taking decisions on the future projects. In the meantime, since no direct path forward is evident for the future projects, the community must be committed to their careful evaluation.