What its all about
Neutrinos are the most elusive of the particles known to the mankind as they interact very weakly with matter. In recent past neutrino physics has provided some of the most interesting and important experimental results in the field of elementary particle physics. In fact, neutrino oscillations (they convert from one flavor to another) have been demonstrated to exist, implying that neutrinos are massive and that they mix. The present "Standard Model" of the fundamental interactions gives a successful mathematical description of all quantum phenomena down to the tiniest scales that can be probed experimentally at accelerators and with cosmic rays.
However the discovery that neutrinos have mass demonstrates that there must be new physical phenomena on even smaller scales, thus setting fresh challenges for our goal of obtaining a complete fundamental understanding of Nature. Therefore, understanding the origin of the neutrino masses could give us important pieces of information on physics beyond the Standard Model which may not be accessible otherwise in any terrestrial experiments and is expected to shed new light on longstanding questions concerning both fundamental physical laws and the nature of the universe as a whole. This discovery also suggests that subtle physical phenomena involving neutrinos may have created the observed preponderance of matter over antimatter in the universe and this has generated intense theoretical interest in this challenging problem.
The problem of neutrinos will be addressed from these four points of view: