英語 での Proton decay の使用例とその 日本語 への翻訳
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Proton Decay Searches: Hyper-Kamiokande.
High energy physics experiment, proton decay experiment.
The"classical" proton decay mode, p e+ π0, can be efficiently detected with low background.
Further, with many more protons to observe it aims to discover rare proton decay phenomena.
In addition, the sensitivity of proton decay searches is also increased.
Proton decay had been predicted in the Grand Unified Theory but, at that time, still had not been proven experimentally.
Especially for neutrino event and proton decay, the R&D of large(<10 kt) LAr-TPC has been started.
These 1,000 large eyes quietly continue watching for Cherenkov radiation in order tocapture the instant that proton decay occurs.
Currently, the most sensitive detector in the world used to examine proton decay is Super-Kamiokande(SK), which contains 7.5x1033 protons. .
In 1983, a proton decay experiment was started as a joint experiment in Kamioka, and the construction of facilities for studying primary cosmic rays was finished.
In this way, while simultaneously continuing to await the instant of proton decay, Kamiokande was detecting solar neutrinos at a rate of once every nine days.
What we mainly do here is investigate the basic properties of particles andthe origins of the universe by means of neutrino observations and proton decay searches.
Proton decay experiments have made fundamental contributions to neutrino physics and particle astrophysics in the past, and any future experiment must be prepared to do the same.
Modern physics is experimentally approaching the origin of matter by conducting high energy accelerator experiments andsearching for very rare events such as proton decay Figure 2.
SK has been performing its observations for more than 12 years,but still proton decay has not been observed and 1034 years has been obtained as the lower limit of proton lifetime.
The proton decay observation experiment had the goal of using PMTs to capture the Cherenkov radiation triggered by the highenergy charged particles that are generated as protons decay. .
The modifications were completed in late 1986.In January 1987 the Kamiokande not only observed proton decay but also neutrinos generated from the nuclear fusion reaction occurring internally in the sun.
If a proton decays into a charged kaon and an anti-neutrino, the kaon will not have enough momentum to emit Cherenkov light, the principal means in which Super-Kamiokande observes particles.
Since the PMTs were to besubmerged in water for long periods of time in the proton decay experiment, a glass material called HARIO 32 was used as the glass bulb because it has superb water-resistance characteristics.
In particular, the project aspires not only to discover CP violation(particle-antiparticle asymmetry) in neutrinos, but to close in on theories of elementaryparticle unification with the world's first discovery of proton decay.
The most important purpose of the Kamiokande experiment was proton decay search. Due to the redundant(highly functional) design of the detector, however, low-energy neutrino could also be detected.
When Professor Koshiba heard of the American plans, he believed he had to do something to offset the smaller scale Japanese plan. He intended to accomplish this by boosting the sensitivity and accuracy for detecting Cherenkov radiation,which serves as proof of the proton decay process.
However, Super-Kamiokande, the most sensitive proton decay detector in the world, has not yet observed this phenomenon and has thereby set a lower limit on the proton lifetime for this decay mode at 1034 years, long enough to reject the simplest GUT.
The PMTs collect the pale blue light called Cerenkov light which is emitted by particles travelling fast as light in the water. By measuring the direction and intensity of this light,information about particle interactions such as neutrino interactions or proton decay can be determined.
The Super-Kamiokande is designed to examine and elucidate the properties of neutrinos,in addition to continuing the work of the Kamiokande experiment by searching for proton decay. Joint research is presently carried out with around 30 universities and research institutes from Japan, the US, Korea, China, Poland, and Spain.
Using 12 years of data the Super-Kamiokande collaboration haspublished a paper describing the search for a signal of this proton decay mode in Physical Review D. Particles predicted by SUSY models have been the target of intense searches by experiments at the LHC, a large collider in Europe, and this paper has accordingly been highlighted as an important result in the study of these theories.
Examples of densely instrumented water Cherenkov experiments: Super-Kamiokande(solar neutrinos, atmospheric neutrinos, far detector for K2K and T2K oscillation experiments);IMB(proton decay experiment, 1979- 1989, which was one of the two water Cherenkovs to detect neutrinos from SN 1987A).
On the other hand, the Grand Unified Theories(GUTs), which can unify the fundamental forces of nature,predict that the proton can decay into lighter energetic charged particles.
The shortest-lived isotope of lithium is 4Li, which decays through proton emission and has a half-life of 7.6× 10- 23 s.