In Japan, the 15 story tall tank of water buried 1000 meters under a mountain has been active for researching on neutrinos that reshapes the standard model of particle physics. The Hyper-Kamiokande(Hyper-K) has been approved by the Japanese government. Hyper-K has been designed to detect neutrinos which are incredibly hard and elusive to spot due to their rare interaction. If we get a lot of matter and stare at all of it for a while, we should notice the telltale sign of a neutrino interaction. The telltale sign in question is known as Cherenkov Radiation. It occurs when a charged particle travels faster than the speed of light through a dielectric medium like water. However, neutrinos have no charge. It comes in 3 types, electron, muon and tau. Neutrino on it’s interaction with water(rarely) converts it into these 3 subatomic particles based on it’s flavor. Electrons, muons and tau particles are charged emitting a cone of Cherenkov light until their speed in water slows down below the speed of light. The end result sensors detect a faint flash of a blue ring of light. 50,000 metric tons of ultra pure water used in Super-K watched by 11,000 golden bulbs called Photo Multiplier Tubes takes the faint light and converts it into an electrical current.
It can detect neutrinos from the sun, atmosphere, etc. due to it’s huge size and sensitivity. It was noted that neutrinos switch between their 3 flavors while travelling. It is believed that Hyper-K will make more precise measurements revealing the different speeds of neutrinos and their antimatter counterparts, anti-neutrinos, cycling through 3 flavors. This difference could be useful to describe the creation of more matter than antimatter at the beginning of the universe. The standard model says decay of a proton is impossible.
But if Hyper-K observes a proton decay, it will change our understanding of the entire universe indicating that 3 of the 4 fundamental forces(Strong force, Weak force, Electromagnetic force)stem from a single fundamental force. Hyper-K should be able to view a proton decay in case their average lifetime is 10^34 years. In case Hyper-K doesn’t detect it, it will indicate the average life of a proton to be 10 times longer. In 2019, researchers added gadolinium in place of ultra-pure water in Super-K to make it more sensitive to antineutrinos. Scientists made 2 testbeds with the acronyms EGADS and GADZOOKS to test the water filtration with the new element.