The Japanese cabinet recently approved the construction of a "top-level Kamioka" neutrino detector and agreed to allocate $ 32 million as the first batch of construction costs. Scientists look forward to this detection "giant" will bring revolutionary discoveries, deepen the understanding of the differences in neutrino and antineutrino behavior, and detect proton decay.
"Top Kamioka" is the "successor" of Japan's existing "Super Kamioka" detector. In 1998, "Super God Gang" provided the first conclusive evidence of neutrino oscillations and sent the person in charge of Takada Putian to the podium of the 2015 Nobel Prize in Physics. The "Top Kamioka" will be the largest neutrino detector to date.
"Top Kamioka" will be built underground in Hida City, Gifu Prefecture, and will be able to detect massive neutrinos from various sources such as cosmic rays, the sun, supernova and particle accelerators. The main facility has a diameter of 68 meters, a depth of 71 meters, and a water storage capacity of 260,000 tons, which is more than five times that of the "Super Kamioka". There are about 40,000 photomultiplier tubes on the wall of the pool. Light.
Putian Takaaki said on the 16th that neutrino physicists are looking forward to the arrival of the "top-level god gang" because it can study the difference in behavior between neutrinos and antineutrinos, which helps explain why the universe seems to be made of matter. leading. "Super Kamioka" has seen some "horse clues", but "Top Kamioka" and the United States "Deep Underground Neutrino Experiment" (DUNE, using liquid argon) should be able to use different technologies to achieve high-precision measurements, thus supporting each other. DUNE will start in 2025. In addition to these two "giants", the Jiangmen Underground Neutrino Experiment (JUNO), located in Guangdong, China, is also one of the three major neutrino experiments that will begin in the 1920s, and it will begin collecting in 2021. data.
Masui Nakamizu, a physicist at the University of Tokyo and a spokesman for "Super Kamioka", said that "top Kamioka" is also expected to discover proton decay. Proton decay has never been observed and is therefore extremely rare, which means that the average proton life span is more than 10 to 34 power years.
In the standard model of particle physics, protons cannot decay, but many theories that attempt to replace the standard models predict proton decay. Proton decay is more likely to be observed because the amount of water used by "Top Kamioka" to detect neutrinos is far greater than that of its "predecessor". If not, it means that the average lifespan of protons will increase tenfold.
It is reported that the total cost of "Top Kamioka" is about US $ 600 million, Japan will provide about 75%, and the remaining funds will be paid by Britain and Canada. Japanese physicists say the Japanese parliament may officially approve the project next month.
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