Why does the nucleus have so much energy? What is quark? Can it be broken down?

The nucleus is very small, with a diameter of10-15m ~10-14m, and the protons in the nucleus repel each other. Because of the strong nuclear force between nuclei, the nuclei can be closely combined into a stable nucleus. It is precisely because of the strong nuclear force between nucleons that certain energy should be released when nucleons combine to form nuclei. The energy released when nucleons combine into nuclei is called nuclear energy, or nuclear energy for short. For example, two neutrons and two protons combine to form a helium nucleus, which will release 28.37 MeV of energy. Quarks and Quarks In 1960s, American physicists Murray gherman and G Zweig independently proposed that hadrons such as neutrons and protons are composed of quarks, which are the more basic units, and many Chinese physicists called them "stratons". They have a fractional charge, which is 2/3 or-1/3 times of the electron charge, and their spin is 1/ 2. The word quark is taken from J Joyce's novel Night Sacrifice in finnigan, written by gherman. Quarks have many meanings in this book, one of which is the sound of seabirds. This is very suitable for his strange idea that "elementary particles are not fundamental and elementary charge is not an integer". At the same time, he also pointed out that this was just a joke and a resistance to the pretentious scientific language. In addition, it may also be the reason why he likes birds. At first, three kinds of quarks were needed to explain the strongly interacting particle theory, which were called quark three flavors, namely upper quark (up, u), lower quark (down, d) and odd quark. 1974 The discovery of the J/ ψ particle requires the introduction of the fourth quark charm quark (Charm, C). The particle υ was found in 1977, which requires the introduction of the fifth quark bottom (b). The sixth quark-top quark (T) was found in 1994 and is considered as the last quark. Quark theory holds that all baryons are composed of three quarks, while anti-baryons are composed of three corresponding antiquarks. Such as protons (uud) and neutrons (udd). Quark theory also predicted the existence of a particle (sss) composed of three strange quarks, which was observed in the hydrogen bubble chamber of 1964 and was called negative ω particle. Quarks are divided into three generations according to their characteristics. As shown in the following table: the Chinese name of the symbol is English name Charge (E) mass (GeV/C 2) U Quark up +2/3 0.004 d Quark down-1/3 0.008 c Charm Quark+2/31.5s Strange Quark strange-65448. 3 0. 15 t top quark top +2/3 176 b bottom quark bottom-1/3 4.7 In quantum chromodynamics, quarks have three "color" characteristics besides "taste", namely, red, green and blue. Here, "color" does not mean that quarks really have color, but uses the word "color" to vividly compare a physical property of quarks themselves. Quantum chromodynamics holds that general matter has no "color", and the "colors" of the three quarks that make up baryons are red, green and blue respectively, so they are colorless when superimposed together. So it includes six flavors and three colors, * * * has 18 quarks and their corresponding 18 antiquarks. Quark theory also holds that mesons are bound states composed of a quark and an antiquark of the same color. For example, Japanese physicist Hideki Yukawa predicted that [[π+meson]] consists of an upper quark and an anti-lower quark, while π-meson consists of an anti-upper quark and a lower quark, which are colorless. In addition to the top quark, five other quarks have been discovered by experiments. China scientist Ding Zhaozhong won the Nobel Prize in physics for discovering attractive quarks. Top quark (T) is a main direction of high-energy particle physicists in recent ten years. As for the sixth "top quark" newly discovered by 1994, I believe it is the last one. Its discovery enables scientists to obtain a complete picture of quarks, which helps to study how the universe evolved in less than a second at the beginning of the Big Bang, because the high heat generated at the beginning of the Big Bang will produce top quark particles. Studies have shown that some stars may become "quarks" at the end of evolution. When a star cannot resist its gravitational contraction, quarks will be squeezed out by a large increase in density. Eventually, a star the size of the sun may shrink to only seven or eight kilometers, but it will still shine. Quark theory holds that quarks are all trapped inside particles and there is no single quark. Some people object that quarks do not really exist. However, almost all the predictions made by quark theory are in good agreement with the experimental measurements, so most researchers think that quark theory is correct. 1997, Russian physicist Diane Konov and others predicted that there was a particle composed of five quarks, the mass of which was 50% greater than that of hydrogen atom. In 200 1 year, Japanese physicists discovered the evidence of the existence of pentaquark particles when they bombarded a piece of plastic with gamma rays on the SP Ring-8 accelerator. It was later confirmed by physicists at Thomas Jepperson National Accelerator Laboratory and Moscow Institute of Theoretical and Experimental Physics. This pentaquark particle consists of two upper quarks, two lower quarks and an anti-singular quark, which does not violate the standard model of particle physics. This is the first time that a particle composed of more than three quarks has been found. Researchers believe that this particle may be only the first member of the "five quarks" particle family to be discovered, and there may be particles composed of four or six quarks. Quarks are the smallest unit of matter recognized by physics at present, and can no longer be divided. However, scientists are still debating whether quarks exist. It is generally believed that matter is composed of molecules, and molecules are composed of atoms, which are composed of basic particles such as electrons, protons and neutrons, while basic particles are composed of sub-particles that are more alkaline than basic particles. Subparticles are also called quarks or stratons.