Neutrinos: the spy of new physics, from matter to stars

Neutrinos , the most elusive and at the same time most abundant particles in the universe, are the sign that something is missing from the Standard Model , the reference theory of modern physics. "In the last 25 years, 3 Nobel prizes have been awarded to neutrinos and this already gives a sign of their importance", Mauro Mezzetto, research director of the National Institute of Nuclear Physics in Padua, told ANSA.

"The last one was awarded in 2015 for the discovery of neutrino oscillations , which demonstrate that these particles have mass. But the Standard Model, as it is, does not predict mass for neutrinos, so - he notes - there must be particles that we do not yet know: we need new physics ". This is why the future of research in this field occupies a fundamental part within the Open Symposium in Venice , which these days sees the entire European community of particle physics gathered to discuss the strategy for the coming years . "Here in Venice all the experiments are represented at the highest levels - comments the physicist from the INFN - so the discussion is very different from a normal conference where you meet only among physicists, it is at a different and extremely interesting level". The experiments are focusing in particular on two themes : on the one hand the asymmetry between matter and antimatter that we observe in the universe and that neutrinos could help explain , on the other the detection of cosmic neutrinos , which carry very important information on stellar processes. "In the first case - says Mezzetto - in the next 3-5 years three large experiments will start in the United States , Japan and China , in which Europe and Italy participate significantly with 40-50% of the researchers ". As for cosmic neutrinos , however, two telescopes are already operational and will be further strengthened in the coming years: one is located in Italy and is KM3NeT , an underwater structure off the coast of Sicily, the result of an international collaboration in which the INFN participates, which in February 2025 announced the capture of the most energetic neutrino ever seen ; the other telescope is IceCube , which is located under the ice of Antarctica and has been in operation for about 10 years. "They are two complementary experiments - concludes Mezzetto - since they are located in different hemispheres".