Scientists have reported the first direct experimental evidence of neutrinos produced by the solar secondary fusion carbon, nitrogen and oxygen cycle, a new astrophysics study published in nature on the 25th. The measurement of these neutrinos can provide important clues for us to understand the structure of the sun and the abundance of elements in the core of the sun. < p > < p > the energy of stars comes from the fusion of hydrogen and helium, which occurs through two processes: proton proton chain reaction and carbon nitrogen oxygen cycle. The former involves only hydrogen and helium isotopes, while the latter relies on carbon, nitrogen and oxygen to catalyze fusion. Among them, proton proton chain reaction is the main energy generation mode of stars similar to the sun, accounting for about 99% of the total energy production, which has been widely studied. However, it is more challenging to study the carbon nitrogen oxygen cycle, because the neutrinos produced by this mechanism are only a few more than the background signals per day. < p > < p > in the gransaso National Laboratory of the National Institute of nuclear physics in Italy, the boricino cooperation organization is committed to the study of extremely rare neutrino interactions. This joint research team is composed of researchers from Italy, France, Germany, Poland, Russia and the United States. < / P > < p > this time, they reported the detection of neutrinos emitted during the solar carbon nitrogen oxygen fusion cycle, with high statistical significance. They used a highly sensitive borrelino detector at the gransaso National Laboratory in Italy. The instrument consists of a container about 18 meters high, which contains 254 tons of liquid. When the electrons in the liquid interact with neutrinos, the liquid will flash and emit light. The brighter flash indicates that the energy is higher, and it is more likely that the neutrinos are produced by the carbon nitrogen oxygen cycle. This detector can eliminate or interpret most of the background noise sources. In the latest study, the team said the results represent the first direct experimental evidence of the carbon nitrogen oxygen cycle to date, proving that the carbon nitrogen oxygen cycle contributes about 1% of the solar energy. < / P > < p > the researchers suggest that the abundance of carbon, nitrogen and oxygen in stars can be determined by measuring the neutrinos produced by carbon nitrogen oxygen fusion. It is believed that the carbon nitrogen oxygen cycle has a greater contribution to the energy production of stars with a mass greater than that of the sun. Understanding the abundance of elements heavier than helium in stars can help us understand the dominant energy sources of different stars. In the “news and opinion” article attached to the paper, Gabriel oleby Gunn, a scientist at the University of California, Berkeley, said that the work of the borrelino collaboration has provided a more comprehensive understanding of the formation of the sun and massive stars, which may define research objectives in this field for the scientific community in the next few years. < / P > < p > in fact, there are two types of nuclear fusion reactions occurring in the solar core. The first is the proton proton chain reaction, in which protons fuse to convert hydrogen into helium; the second is the carbon nitrogen oxygen cycle. These two types produce different neutrinos. These almost massless subatomic particles can pass through ordinary matter without any sign most of the time, which is difficult for us to detect, especially the second type. However, many sensitive detectors are arranged in a large water tank inside the Bresciano instrument. They are isolated from the background radiation of cosmic rays on the earth’s surface, preventing other signals from “drowning out” neutrinos from the carbon nitrogen oxygen cycle, and finally help scientists detect the rare signals generated by this cycle.