Super-Kamiokande

Welcome to Super-Kamiokande!

One of Super-Kamiokande’s (Super-K) main research focuses is the study of neutrinos. Neutrinos are a type of elementary particle, similar to electrons and quarks, but they are unique in that they carry no electric charge and interact with matter only very rarely. Detecting these elusive particles requires a large amount of material, which is why the Super-K tank contains 50,000 tons of ultra-pure water. Although neutrinos were once thought to be massless, Super-K’s discovery of neutrino oscillations—a phenomenon where neutrinos change from one type to another—revealed that they do, in fact, have mass. This groundbreaking finding demonstrated that the Standard Model of particle physics is incomplete, paving the way for new and advanced theoretical models.

Because neutrinos interact so weakly with matter, they can be used to study both the deep interiors of stars and the vast expanse of the universe. For instance, neutrinos enable us to observe the core of the Sun, where nuclear fusion generates the energy that powers life on Earth, as well as the dramatic collapse of a massive star’s core during a supernova explosion. Additionally, neutrinos produced by all the supernovae since the universe’s inception, known as “supernova relic neutrinos,” are still traveling through space today. Observing these supernova relic neutrinos would provide valuable insights into the universe’s history and evolution.

Another key research area at Super-K is the search for proton decay. Under the Standard Model, protons are stable and do not decay, as they are the lightest members of their particle family. However, if particles like electrons, neutrinos, and pions are part of the same particle family as the proton, the proton could theoretically decay into these lighter particles. Detecting proton decay would confirm this relationship, offering direct evidence for Grand Unified Theories—a class of theories that aim to unify all fundamental particles under a single framework.

In August 2020, the SK detector entered a new era with the introduction of gadolinium, a rare earth element, into its ultra-pure water. This enhancement significantly improved the detector’s sensitivity to neutrinos and opened the door to the first-ever observation of supernova relic neutrinos.

In closing, I would like to express my gratitude for your interest in Super-K and invite you to follow our future discoveries with anticipation.