China's annular electron positron collider cepc: once completed, it will

In 2012, European Nuclear Research Organization (CERN) announced that the Large Hadron Collider (LHC) had discovered the "God particle" - Higgs particle, which put its prophet on the Nobel Prize podium in 2013, and then opened a new era of particle physics research - a number of high-energy cutting-edge experimental devices based on accelerators around the world have been established and become the development trend of particle physics research.

In september2012, the Institute of high energy physics of Chinese Academy of Sciences also proposed to build the next generation Ring Electron Positron Collider (cepc) and timely transform it into a high-energy proton Collider (SPPC).

On August 1st, 2016, the "International Conference on string theory" kicked off at Tsinghua University. Top international theoretical physicists gathered together to discuss the frontier issues of physical research, and accepted an interview with the reporter of China Science Daily on the scientific value and development prospect of China cepc project.

If no new particles can be found

According to the planning assumption, cepc will be a ring accelerator with a length of 50 ~ 70 km, which can produce a large number of Higgs particles, so that scientists can accurately measure and study Higgs particles and other standard model particles. Of course, scientists expect to find new physics (new particles or new phenomena) in the high-energy region of the experiment.

However, if the cepc experimental device can not find new particles, does it mean that cepc has not achieved its scientific goals? During the interview, experts responded to this.

"In fact, the accurate measurement of the Higgs particle itself has very important scientific value." Nobel Prize winner and American particle physicist David gross told reporters that of course, new particles may also be found in the experiment.

It is understood that theoretical physicists have done a lot of work to describe the next development direction of particle physics. For the cepc project, "even if no new particles are found, it is equivalent to excluding the corresponding areas". Cumrun vafa, Professor of the Department of physics of Harvard University, told reporters that the efforts made by Chinese scientists and engineers in the construction of this device are of great significance to the development of Chinese science. Therefore, in his view, "failure to find new particles does not mean failure".

In addition, the collider can help scientists understand the structure of small-scale matter and better understand the concepts of time and space. The theoretical assumptions of future research such as cosmology and dark matter need to be further verified in experiments. "This is also the reason for our further efforts." Said Robert dijkgraaf, Dean of the Princeton Institute for advanced studies.

Benchmarking science project

"The value of basic research cannot be directly measured by commercial value." When talking about the value of cepc project, David gross said.

He told reporters that once completed, cepc will be the largest Ring Electron Positron Collider in the world. Although it can not directly generate commercial and social value in medical, pharmaceutical and other fields, it will be accompanied by many technical by-products, which will affect people's lives.

"Basic research will indirectly promote technological development." David gross said, "although it does not directly promote the current scientific and technological development, its indirect effect will be more influential than the direct effect."

In the opinion of experts, the pursuit of the most basic natural problems is very wonderful. It will produce many unexpected results. "Lasers, nuclear magnetic resonance, etc. are good cases of by-products of basic research." David gross added.

During the interview, many scientists expressed great expectation for the possible benchmarking demonstration effect of cepc project. As Edward Witten, an American theoretical physicist, said when commenting on cepc, "once the device is completed, it will undoubtedly become the most cutting-edge Collider in the world and will lead the world in the next few decades."

Because of its leading position, Professor qiuchengtong of Harvard University is optimistic about the positive impact on Chinese education and millions of Chinese parents.

"It is of great significance to expose children to world-class scientific devices." Qiu Chengtong said that in the past period of time, many middle school students in China went abroad to study in developed countries in Europe and the United States. Once the cepc project is successfully constructed, it will give Chinese parents and children confidence that China can also make advanced scientific achievements, so as to attract more outstanding young people to learn science.

International cooperation is of great significance

Particle physics research is a very open scientific field, and has a good tradition of international cooperation.

"International cooperation in the field of high energy physics is very extensive, which is a very good tradition." Therefore, David gross hopes that scientists from China, the United States, Europe and other countries and regions will actively cooperate in the promotion of this project.

During the interview, experts expressed optimism about China's economic development and its possible long-term support for scientific research. However, they also stressed that it is unrealistic for a country to undertake such a large scientific project. Only by reducing the cost of time and space through international cooperation can the process of the project be effectively promoted.

It is reported that China has a certain foundation and confidence to complete the construction of the first phase of cepc. However, to upgrade to the proton collision stage, relevant technologies at home and abroad still need some time to develop, and they are not available at present.

It is gratifying that this project has received extensive support in the United States, Europe and other countries and regions. "Physicists in the United States and Europe all support this project." Qiu Chengtong told the reporter positively.

During the interview, the experts are looking forward to the future of cepc project. They firmly believe that such a large scientific project will have extraordinary significance for China's scientific development.

Because, with the promotion of the project, China can not only become a leader in relevant fields, but also attract a large number of world top scientists to China for exchange and work, and even take root in China, which will have a huge and far-reaching impact on China's scientific development.