The "super racetrack" of the microscopic world: China plans to build the world's most powerful "particle bumper car"

Produced by: Science Popularization China

Author: Guo Fei (Yantai University)

Producer: China Science Expo

In science fiction movies, we often see future technology that can freely enter and exit the microscopic material world. Now, such science fiction scenes are becoming a reality in China. Underground, in a 100-kilometer-long tunnel, a huge "microscope" may be born, which can allow us to peek into the deepest secrets of the earth and even the universe.

This is the world's largest particle collider that China plans to build - the Circular Electron Positron Collider (CEPC). It will not only promote the progress of basic scientific research, but may also completely change our understanding of the universe.

Unveiling the secrets of particle colliders: the "super racetrack" of the microscopic world

A particle collider is like a "super racetrack" in the microscopic world. In this sophisticated device, scientists use sophisticated and complex accelerating electric fields to make tiny particles run at speeds close to the speed of light, bypass long tunnels, and collide at specific locations.

When two beams of high-speed particles collide at a predetermined "observation point", it is like creating a miniature "Big Bang" on the subatomic scale. This high-energy collision allows us to observe physical phenomena that are usually hidden. The reason is that according to Einstein's famous mass-energy equation E=mc², we can know that huge amounts of energy can be converted into matter. Therefore, in these high-energy collisions, the huge amount of energy released instantly can create various phenomena that are not common in our daily world, and also give us the opportunity to peek into the structural mysteries of microscopic particles.

What's even more exciting is that this high-energy collision can also reproduce the high-energy state at the moment the universe was born. By simulating the high temperature and high density environment in the early universe, we can better understand how the universe evolved from a singularity to the vast starry sky we see today. It's like having a "cosmic time machine" that gives us the opportunity to study what the universe looked like in its infancy.

This is why the circular accelerator is regarded as one of the most important tools in modern physics. It is not only a "super microscope" for exploring the microscopic world, but also a "time machine" for studying the origin of the universe.

The Compact Muon Solenoid (CMS) detector at the Large Hadron Collider (LHC), with the ladder at the lower right highlighting its size.

(Image source: Wikipedia)

The particle collider that China plans to build is called the Circular Electron Positron Collider (CEPC). Its main goal is to study the Higgs boson, a mysterious particle discovered in 2012 and nicknamed the "God particle." Like the core spell in a magic book, the Higgs boson is believed to be able to give other particles mass.

By studying it in depth, scientists hope to answer some of the most fundamental questions in the universe: Why does matter have mass? How did the universe evolve? Why is there more matter than antimatter in the universe?

There are six quarks (in purple) and six leptons (in green) in the Standard Model. In addition to fermions, there are four gauge bosons (in red) and the Higgs boson (in yellow).

(Image source: Wikipedia)

CEPC is like a tool to help us decipher this core spell. By building this "super microscope", Chinese scientists are making important contributions to human exploration of the mysteries of the universe and are expected to make major breakthroughs in basic physics research.

CEPC: The crystallization of scientific and technological innovation

The design of CEPC is an engineering marvel that combines cutting-edge technologies. This giant "track" consists of an underground tunnel with a circumference of 100 kilometers, which is equivalent to the length of 250 standard 400-meter running tracks connected end to end. In this huge facility, particles will be accelerated to nearly the speed of light, producing high-energy collisions. What makes CEPC unique is not only its size, but also its efficiency and precision. It can produce millions of Higgs bosons every year, which will allow scientists to measure the properties of this mysterious particle with unprecedented precision.

Group photo of the CEPC team, the International Advisory Committee and some members of the International Review Committee of the CEPC Conceptual Design Report

(Image source: Institute of High Energy Physics, Chinese Academy of Sciences)

What's more exciting is that if everything goes well, CEPC is expected to start construction in 2027 and take about 10 years to complete. This means that it will be completed at least a few years earlier than Europe's Future Circular Collider (FCC) plan, and China is likely to gain an advantage in this technological competition.

Challenges and opportunities coexist: building a world-class scientific research platform

However, it is not easy to turn the grand plan of CEPC into reality. Building such a large and sophisticated device requires breakthroughs in many cutting-edge technologies, from superconducting magnets to precision control systems, and each component requires extremely high precision and stability. It is like assembling a super-precision watch, and every part cannot be wrong.

The engineering challenges are equally huge. Digging a 100-kilometer-long underground tunnel requires consideration of complex geological conditions and environmental impacts. Currently, the three cities of Qinhuangdao, Changsha and Huzhou are competing for the site selection of CEPC, and each location has its own unique advantages and challenges.

Inside the CERN LHC collider tunnel

(Image source: Wikipedia)

Despite these challenges, the CEPC project also brings great opportunities. It will promote the development of China in many high-tech fields, from superconducting technology to precision manufacturing. More importantly, it will train a large number of world-class scientists and engineers for China, laying a solid talent foundation for future scientific and technological innovation.

Looking to the future, if the CEPC project is successfully implemented, it will open a new window for mankind to understand the universe. The CEPC project is undoubtedly a bold scientific and technological adventure, but it is this spirit of courage to explore the unknown that drives human civilization forward. Regardless of the outcome, China's courage to propose and promote this grand plan has demonstrated the ambition and responsibility of a major scientific and technological power. Let us look forward to this huge "microscope" made in China to help us uncover more secrets of the universe!

References:

1. Nature, China could start building worlds biggest particle collider in 2027

2. Wang Yifang, building a large accelerator to realize the scientific dream