I feel that I have not written very well recently and I don’t have much passion. On the last day of May Day holiday, I’d better take a day off and update it normally tomorrow.

After all, the author Jun is not Zhang Yuan. He can burst into liver all day long without knowing how tired he is, and needs a normal rest... (I also seem to have become him qaq)

Finally, let’s have a popular science article. The article written by an academician is quite good. If you are interested, you can read it.

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Opinions on China's construction of a large collider

He Zuoxi, Researcher at the Institute of Theoretical Physics, Chinese Academy of Sciences, Academician of the Chinese Academy of Sciences

Written by | He Zuoxiu (researcher at the Institute of Theoretical Physics, Chinese Academy of Sciences, and academician of the Chinese Academy of Sciences)

Editor-in-chief | Lu Haoran

1

The cepc-spc project suggested by Wang Yifang, director of the Institute of High Energy Physics of the Chinese Academy of Sciences, etc. is not an innovative project. The overall design idea is borrowed from LHC and amplified, and the project funding is also very large. The planned energy of the SSC project in the United States is 20Tev; Italy, that is, Europe once had an Eiosatron project larger than the SSC in the United States, with a higher planned energy. Now the energy of the SSC proposed by Wang Yifang is 70-100Tev, which is actually similar to that of Eiosatron. The latter died without discussion from multiple countries and encountered opposition from many high-energy physics scholars in Europe.

The United States held a fierce debate for SSC, and finally the dispute came to Congress, which was voted by Congress and finally rejected. Some people said that this was a victim of the political debate between the two parties, and it was not right! Regarding the decision-making of the SSC project, the state's financial management personnel believed that this project did not have much scientific value and cost a lot, which would affect the country's development capabilities, so they eventually abandoned it. Of course, many high-energy physicists expressed their support, but many high-energy physicists expressed their persistence in opposition, believing it was a big waste! In the end, Congress adopted the opinions of the opposing party and voted to reject it.

It should also be noted that the degree of the US "veto" is surprising! The US government has invested $2 billion, mainly to dig a large tunnel, and the cost of the tunnel accounts for about 10% of the total cost in the planning. Later, it is required to allocate an additional $15 billion to $20 billion in order to achieve the final achievement.

But the result was that Congress would rather sacrifice the $2 billion it should invest than allow such ineffective investment. After Congress rejected it, even the tunnels that had been excavated were filled and were not allowed to be "resurrected."

2

Why did the US Congress question the opinions of many experts and finally reject the SSC project after the Congressional debate? Another important reason in academics is that there is an important theory in particle physics theory, that is, particle physics will develop towards ultra-high energy physics, and there will be no new discoveries. This is called the "big desert" theory of high energy physics.

The "Great Desert" theory believes that at least the energy must be increased to the Planck scale, that is, energy equivalent to 10^16tev, so that high-energy physics can make new discoveries. Later, some high-energy physics scholars believed that this theory was not completely correct and should be revised. The correction method was to introduce the concept of "supersymmetry" and believed that with these supersymmetric particles, their energy standards would be reduced by many orders of magnitude, but they were still much higher than the order proposed by SPPC! Later, several accelerators such as the United States and Europe tried to discover these supersymmetric particles, but they found nothing. This also indirectly illustrates the rationality of the "Great Desert" theory. Therefore, the US Congress rejected the continued construction of the SSC project with overwhelming votes.

Of course, the "missing" of supersymmetric particles immediately led to a major fundamental change in view, that is, the superstring theory carefully crafted by many particle physicists and mathematicians also "falls"! The so-called "falls" here are targeting the theory that superstring theory is meaningless in physics. However, it is not ruled out that it has certain significance in mathematics.

But there are still quite a few theoretical physicists who do superstring theory. Supersymmetric particles do not think that supersymmetry is dead and are still insisting on it. However, few people have believed that this is a promising theory in particle physics, and have announced that they will not do it. For example, Professor Li Miao, who has made great contributions to superstring theory in the Institute of Theoretical Physics, has now given up not doing it. In other words, superstring theory is no longer the mainstream in the high-energy academic and particle science community!

3

Combining the above two arguments, I can only think that the cepc-spc plan proposed by Director Wang Yifang is just an "innovation" that has been completely abandoned by the US Congress, but at this time many scientists have taken it to the Chinese government.

As for whether the Chinese government is willing to spend huge amounts of money to build, it depends on how the Chinese government evaluates the matter.

We should also note that many of the people who promote the collider project are American experts such as academicians of the American Academy of Sciences. They said that this plan has "many benefits". Of course, since China's research on high-energy physics is far less advanced and developed than that of the United States, it may be that we are short-sighted and have no scientific vision. However, there is still a question that makes me unable to understand: why such a good plan is not accepted by the American science and technology community? Why does such a good plan not insist on lobbying the US government? If the US government announces that it will launch this "innovation" plan and hopes that China can also contribute a large amount of funds to join the cooperation, I believe it will definitely receive strong support from many scientists in the high-energy physics community in my country!

4

There is an answer to our question: this plan still has far-reaching significance for the research of high-energy physics in developing countries, such as China. I cannot agree with this. We have always agreed with the saying "science has no borders, scientists have their motherland". We cannot agree with a plan that has no significance to world science but has "huge significance" for the motherland of Chinese scientists. There are too many scientific problems that contemporary China needs to solve, and many young people need to participate in this work. But we cannot think of a plan that is not very "effective" to accommodate these high-energy physics scholars!

The world is a whole. The development of economics and science in contemporary countries in the world must follow the path of "integration" and "globalization". Recently, I have been studying and researching economics and political economy in my spare time. Many conclusions of economics should also be applicable to the development of world science.

We know that there is a law of decreasing marginal utility in economics, which can be applied to a wide range. For example, why did my country's economy change from an earlier average increase of 10% to 6.9% today? The simplest explanation is the decreasing marginal utility. And the way to alleviate this impact is to rely on innovation. These basic principles must also be applicable to the research of high-energy physics.

Judging from the proposals suggested by Wang Yifang and others, this plan is characterized by no revolutionary technological innovation at all and is only developing towards "super-large", so it must be applicable to the law of decreasing marginal utility.

There is a technical difficulty in applying the law of decreasing marginal utility, which is that it is difficult to judge how fast the "marginal utility" "decreases" at, and how much will it "decrease" in the future "margin", that is, the "slope"? In fact, the recent experiment of lhc has given a judgment.

During the previous period, LHC discovered a 750gev "former peak" in the energy range of 700-800gev. The academic community was very excited because it seems that there may still be new discoveries for high-energy physics to "go high places", and the theory of "big desert" is inconsistent with the practice! However, due to the insufficient number of experiments, it is impossible to clearly believe that this is a new particle. Therefore, some people advocate more operation time and expenses in order to fish out this "new particle". A large number of theorists also believe that this is a new thing, and have made many "new" theories to explain this particle and make various new predictions.

However, most theoretical physicists who insist on believing in the "Great Desert" theory still believe that this so-called "new particle" should be statistical fluctuations, not the discovery of any new particles.

The result is that further high-precision experiments have not confirmed the existence of "new particles"! The "Great Desert" theory is still correct in this energy zone. It should be noted that the energy of 750gev is actually 6 times that of the Higgs particle 125gev, known as "God Particle", but the result is still zero. If interpreted in economic terms, this experiment has shown that the "marginal utility" of the high-energy collider in the energy zone of lhc has decreased to "zero".

Now, in the plan proposed by Wang Yifang, the maximum energy is only 7 times that of lhc. If we continue to do this according to this trend, how can we ensure that new particles or other major new things be discovered? Not only that, the Geneva Center will also further increase its energy to 20tev and continue to engage in experimental work. However, Geneva already has a super-large accelerator, and the West only needs to invest some money again to achieve marginal benefits. However, China wants to restart the stove, which is only 7 times more energy, but it has to retrace the long journey that the Geneva Center LHC has gone through.

Or the plan of Wang Yifang and others is by no means an equal competitor in Geneva.

The lhc of the Geneva Center has made great contributions to high-energy physics. It has been operating for 20 years and has discovered four important particles in succession, and has almost perfectly proved the correctness of the "standard model". Now there is only one small question left, that is, the question of whether the lepton number is "absolute" conservation has not been completely solved. However, the answer to this question does not require ultra-high energy accelerators to study, but requires medium and low energy accelerators, such as the spalling neutron source, ads and other projects that have been established by the Academy of Sciences to answer.

It can be said that the current development trend of high-energy physics is completely corresponding to the supply curve repeatedly emphasized by Prime Minister ***, and will extend to the "right" according to the "s" trait. However, at this time, there are already "Great Desert" theory and experimental results of lhc, which all indicate that the "marginal utility" of this extension has generally approached zero, that is, the curve of the "s" shape is close to the "vertex".

So, why does China today have to make significant investments in this cepc-spc that is difficult to produce major results?

5

Of course, Director Wang Yifang has always emphasized that the high-energy institute never overspending when building a positive and negative electron collider, and the up and down fluctuation will not exceed 5%. It should be said that this is a historical fact. As a witness to the Beijing Positive and Negative Electronic Collider, I want to tell some stories behind it.

The Institute of High Energy built a positive and negative electron collider after the Cultural Revolution. Comrade *** was a large-scale basic research project based on Premier Zhou's last wishes. The total cost was 220 million yuan. Since this was the first large-scale scientific research project specially approved by the central government after the reform and opening up, the central government once greeted all parties: This is not a piece of "Tang Monk's meat", and all ministries and commissions should not take the opportunity to "chew a bite". This "helping" was also spread to Hong Kong, which had not returned at the time. The Hong Kong industry said that this was a project specially approved by Comrade Xiaoping, and we must strongly support it. Even if we don't make money, we will try to ensure supply.

In order to ensure that the positive and negative electron collider is carried out as planned, the central government also specially sent Comrade Hu Qiaomu's wife, Comrade Guyu, to take charge of this work. When difficulties are encountered, Comrade Guyu will coordinate. For example, when the construction of the positive and negative electron collider started, residents nearby were worried about radioactive pollution and expressed opposition. Therefore, the environmental protection department sent a department-level cadre to participate in supervision. However, the cadre lacked professional knowledge reserves and simply expressed opposition.

We asked her to come up with a corresponding "indicator". What kind of standards should she reach to pass, but she could not give a specific value. At that time, the leaders of the Institute of High Energy entrusted me to organize some young comrades to design protective devices for high-energy accelerators. Since the cadre sent by the environmental protection department was really "outsider", we could not give a specific indicator, and of course we also suspected that she had the meaning of "chewing a bite".

Therefore, Comrade Guyu went to Comrade Xiaoping to report the situation, and Comrade Xiaoping finally decided that we would be responsible.

Of course, our design was completed quickly. Because this collider is a positive and negative electron collider, which only emits x-rays and gamma rays, and its impact on the environment is smaller than that of the cosmic ray background.

The question is, in the current era, can the "wishness" of Director Wang Yifang be realized again? The conclusion should be: This is a plan that does not conform to China's national conditions and decision makers should not support it.

6

Director Wang Yifang also said that almost all opponents are experts outside the field of high-energy physics. I think this is by no means a fact.

Here (Institute of Theoretical Physics) we also have a group of members of the High Energy Physics Society, and many of them expressed opposition. In fact, there are some different opinions within the High Energy Institute, but they are embarrassed to publicly express their feelings due to the feelings of their colleagues.

Previously, Professor Yang Zhenning published an article opposing China's construction of large-scale colliders. Some people also pointed out that Mr. Yang has been away from the front line of physics for many years and has deviated from the mainstream of physics. These doubts are not correct. Although Professor Yang is old and has not been on the front line for many years, Mr. Yang's views on theoretical physics cannot be said to be outdated or deviated from the mainstream. Historically, Mr. Yang's judgment on the future of physics cannot be said to be insignificant.

Recently, Director Wang Yifang has proposed that almost all high-energy experimental physicists agree with China's large-scale collider project, and opponents are all theoretical physicists, and some questions have been raised about the opponent's profession, including Professor Yang Zhenning, who is not an experimental physicist.

OK, then I will also list a scholar who can definitely be called a high-energy physics experimenter in the world, and also the teacher of Director Wang Yifang - Professor Ding Zhaozhong. Professor Ding once asked me what research Wang Yifang is currently engaged in. I replied that he is still measuring neutrino oscillations in Daya Bay. In addition, he is studying some new solutions. Professor Ding asked what new solutions it was? I said that he wanted to move similar SSC solutions discussed in the United States to China. Professor Ding immediately said, why do you want to do this? There is no meaning at all!
Chapter completed!