Kim Young-ki, chair professor of the Department of Physics at the University of Chicago, is giving a presentation at the Science Innovation Conference ‘Advanced Science, 50 Years to Come’ hosted by Choi Jong-hyun Academy on July 28. Provided by Choi Jonghyun Academy
The invisible atom has been known for centuries as the smallest basic unit of matter. However, the belief that the atom is the most unitary was devastated by modern particle physics in the 20th and 21st centuries. One by one, the existence of much smaller particles, such as quarks and electrons, was revealed. The accelerator, emitting huge energy, guided human attention to the world of smaller particles, much like looking into cells through a microscope. Just as scientists have uncovered the existence and power of smaller particles that make up matter over the past half century, scientists are expected to continue the challenge of looking into a smaller world.
Kim Young-ki, chair professor of the Department of Physics at the University of Chicago, said at the scientific innovation conference ‘Advanced Science, 50 Years to Come’ held by the Choi Jong-hyun Academy on the 28th, “Research to explore a smaller world with a bigger and more powerful energy accelerator will continue in the new 50 years.” said.
Professor Kim received his bachelor’s and master’s degrees from the Department of Physics at Korea University and his doctorate from the University of Rochester, USA. He served as a professor at the University of California, Berkeley, and then as head of physics at the University of Chicago. For 7 years, he served as deputy director of the US National Fermi Institute and president of the Korean American Association of Scientists and Engineers. In 2024 he is due to rise to the chair of American physics. Professor Kim, an experimental particle physicist, has been conducting research to find the origin of elementary particle mass using high-energy accelerators and powerful detectors. The American science magazine ‘Discover’ selected him as one of ’20 scientists who will lead the world’s scientific development for the next 20 years’ in 2000. It was at this time that he earned the nickname ‘Queen of Conflict’.
In this lecture, Professor Kim introduced the remarkable achievements of particle physics that have been with accelerators for 50 years and the tasks for the next 50 years. According to Professor Kim, the world that humans can see is getting smaller and smaller through the exploration and overcoming of the smallest particles. Instead of small tweezers or a microscope, a huge experimental device called an accelerator is being used here.
For centuries, the Greek philosopher Democritus introduced the concept of the atom as a basic and indivisible fragment that makes up the world, including solids and liquids, 2,500 years ago. However, with the advent of accelerators, that belief has continued to be broken over the past 100 years. Professor Kim said, “Atoms are no longer the smallest beings.” In 1897, electrons were discovered in the atom, and within 10 years, the nucleus of an atom, which was only 1/100,000th the size of the atom, and 20 years later, the existence of protons and neutrons, which were only 1/10th the size of the nucleus, was discovered. Although only 1/1000 of a proton, quarks, the fundamental particles that make up electrons and matter, have also been discovered.
As humanity sees a smaller world, the scale is becoming more sophisticated. The atomic scale uses nanometers (thousandths of a nanometer) because quarks and electrons are much smaller than a nm. As the smaller particles that make up the particles were revealed, the identity of the forces exchanged between them was also revealed one following another. The quarks that make up the nucleus of an atom are governed by a strong nuclear force, and the electromagnetic force between the electrons and the nucleus of the atom dominates. Professor Kim said, “The periodic table, which organizes numerous element types, is a great achievement of science in the 19th century, but as a result, the interior of all elements is composed of up quarks, down quarks, and electrons.”
Professor Kim said, “Light and electron microscopes were invented to see the small world, but to see things much smaller than nanometers, you need an accelerator, a more powerful microscope.” Putting in a lot of energy creates a beam with a shorter wavelength that allows us to see a smaller world.
A collision-type accelerator is a device that creates a very high energy beam and collides head-on. During this process, the particles annihilate each other, but the energy is conserved, creating very large particles that are presumed to have existed just following the Big Bang 14 billion years ago. This is why scientists call an accelerator that creates an environment similar to the early universe with high energy as a ‘time machine’.
Professor Kim said, “The Large Hadron Accelerator (LHC) owned by CERN is like a time machine that goes back to the early universe with modern technology.” The standard model, which consists of 6 quarks, 6 leptons, and 4 mediators, is a living history of particle physics. The sites of discovery of new particles that have appeared in the 50 years since 1972 overlap with the Stanford Linear Accelerator Center (SLAC), the Brookhaven National Laboratory, the US Fermi Laboratory, and the European Particle Physics Laboratory (CERN). Charm quark, taurepton, top quark, and mediator particles gluon, W boson and Z boson were discovered one following another at these laboratories. In 2012, a Higgs boson, the ultimate particle that gives mass to elementary particles, was also discovered in CERN’s Giant Hadron Accelerator.
In this regard, Professor Kim said, “The standard model is perfect and explains many parts,” but “discovering particles and making a table of standard models is not all regarding particle physics research.” “Ultimately, we need to understand the interaction of natural laws through particles and forces,” he said. It is not yet known why the elementary particles of the standard model have different masses. Also, the area that the standard model cannot explain for strongly interacting quark particles remains to be solved.
Professor Kim said, “Visible stars, galaxies, and cosmic dust are just the tip of the iceberg that makes up the universe.” It remains homework.” Professor Kim said, “Aristotle left a famous saying that the more you know, the more you know that you don’t know, and that statement fits perfectly in the study of particle physics.”
Professor Kim said, “Since Ernest Lawrence, a professor at the University of California, Berkeley, USA created the first accelerator that accelerates particles in a magnetic field by combining magnets and wires in 1929, scientists have been demanding higher energy and larger accelerators.” The collision energy ranges from 60 billion eV (electron volt) in the 1980s to 13 TeV (1 TeV is 1 trillion eV) in the current LHC. The accelerator experiment, which initially had only three or four participating countries and only a few dozen researchers, has now grown to a scale of more than 3,000 researchers from 40 countries. The size of the data has also grown as better algorithms are now applied through big data and artificial intelligence (AI) to the experiment of whether or not a collision will occur once in a billion collisions. Research programs at CERN, the Fermi Institute in the United States, and the Institute of High Energy Physics (KEK) in Japan provide researchers with access to powerful energies.
Professor Kim said, “When pioneering new particle physics in the 1950s, there was a case in which a technology was conceived to realize 1 TeV energy by rotating the Earth once in order to collide with higher energy. “Competing, we have achieved astonishing results in half a century with a much smaller facility.”
Professor Kim said, “It is clear that higher energy accelerators will emerge and research in this field will continue. ” he said.
Kim Young-ki, chair professor at the University of Chicago, Ha Taek-jip, Johns Hopkins University professor, Andrea Guez, professor at the University of California, Los Angeles, and Nima Arkanihamed, a professor at Princeton High School are having a discussion at the ‘Science Innovation Conference’ hosted by Choi Jong-hyun Academy on July 28. . Provided by Choi Jonghyun Academy
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