Science Network June 5438+February 4, 2007 Swedish scientists recently suggested that if the quarks that make up protons and neutrons are indeed made up of smaller particles-precursors, then precursors with higher density than neutron stars and quarks may be detected in the universe, and their density is just like concentrating the mass of the moon on an object the size of a pea. Related papers were published online in Physical Review D. Lu Le? Fredrik Sandin and Johan Johan Hansson of the University of Science and Technology said that this precursor may exist in the ultra-dense blocks after the Big Bang, and these objects can be detected by the existing astronomical observation technology. This conclusion makes a highly uncertain hypothesis a testable point of view. If precursor stars do exist, they may account for a large part of the mass of dark matter in the universe. For a long time, human beings have gradually known the composition relationship between various particles. Atoms consist of protons and neutrons (collectively called hadrons) and very light electrons. Hadron consists of six types of quarks. In addition, there are six basic particles related to electrons-leptons. In 1974, physicists Jorge Patty and abdul sallam speculated that a family of particles called "precursors" might explain the difference between quarks and leptons. From 1999 to 2002, Hansen and his colleagues published in High Energy Physics-Phenomenology (http://www.arxiv.org/abs/hep-ph/9909569) and European Physics Letters (J. Europhys. Lett.60,188–194, 2002) thinks that three types of precursors are enough. In 2005, Hansen and his student Sundin continued to study whether substances can be combined into blocks in the precursor state instead of "condensed" into quarks or hadrons, and the answer is possible (Phys. Lett.b 66, 1-7, 2005). These pre-subblocks (pre-sub-stars) are denser than quarks and neutron stars. Researchers believe that the front sub-block can't be formed by the collapse of stars, but it may be the remains of the Big Bang. When the new universe expands, the matter in it becomes thinner and thinner, thus changing from precursor matter to quark matter, and finally becoming atoms used to build stars and interstellar gas. However, Hansen said that some precursors in the early universe may combine to form stable "bubbles", and the above changes have never happened. The researchers calculated that the mass of these precursor "bubbles" is less than that of ordinary stars, and will not exceed 100 times the mass of the earth, and the diameter will not exceed one meter. Although there is no lower limit, Sandin and Hansson think that the smallest front sub-block should be the size of a pea, and its mass is slightly smaller than that of the moon. It is conceivable how difficult it is to find such a celestial body in the vast universe. However, researchers say there are still some ways to find them. First of all, from the earth's point of view, these ultra-dense celestial bodies can bend the light coming from the back around them, which is the so-called "gravitational lens effect". Sandin and Hansson said that because the front sub-blocks are very small, they will have the strongest impact on cosmic gamma rays-making the gamma ray spectrum have a special swing. If the first two sub-blocks happen to form a double "star" system with * * * orbits due to gravity and are located near the sun, the gravitational waves (spatio-temporal fluctuations) they emit will be captured by gravitational wave detectors. However, if these two pre-sub-blocks are very small, the high-frequency fluctuations they emit can be detected only by desktop equipment without using the existing large detectors. In addition, once the tiny front sub-block hits the earth, it will also stimulate detectable seismic waves. Hansen said that they are too small to drill a hole in the earth. But they will leave traces of seismic waves on the straight-line motion path, which is obviously different from the friction between continental plates. Now, it seems impossible to create a precursor, because it needs to recreate the scene in BIGBANG. So, how will other physicists react to the statement of the former daughter Xing? Hansen himself said, "They are either very keen on it or think it is worthless garbage, and there are not many people in between." However, John Charap, a theoretical physicist at Queen Mary College in England, seems to be such a middleman. He said, "This is not an idea of stark raving mad. After all, we need some good crazy ideas to promote our understanding of dark matter. We are now trying to find a reasonable explanation for dark matter, and new ideas may be good candidates like others. "

Glue. Each nucleus is made up of protons and neutrons, and protons and neutrons are made up of quarks, which are connected by gluons! ! ! The theoretical size of quarks is only much smaller than that of nuclei. For example, a proton or neutron consists of three quarks and gluons. It can be seen that quarks are not much smaller than nuclei. The mass of electrons is11836 of protons or neutrons, which should be small enough. In recent years, there is still a hot issue in physics, that is, neutrinos. There are trillions of neutrinos passing through the body every second, but we don't know it at all, because it is too small and may have no mass (some scientists say it is one millionth of the mass of electrons). Quark is smaller than it, so it can only give up. Glue. A particle that theoretically predicts strong interaction between quarks. ***8 species, static mass 0, spin 1, with color charge. The electromagnetic interaction between charged particles is realized by exchanging photons; Similarly, the strong interaction between quarks with colored charges is realized by exchanging gluons, but the difference is that photons have no charge and cannot emit or absorb photons themselves; Gluons have colored charges, and there is also a strong interaction between gluons. Gluons themselves can release or absorb gluons. Free gluons have not been found in the experiment, but the deep inelastic scattering experiment of electrons on protons in 1968 shows that there is a point structure in protons, and only half of the energy of protons is carried by charged point substances, and the other half is carried by neutral components without electromagnetic action. According to the quark model, the charged point structure is quark and the neutral component is gluon. The experimental results provide the possible signs of gluons. In 1979, the phenomenon of three jets was found in the high energy electron-positron collision experiment, which further explained the existence of gluons.

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