Deep Space Fleet

I feel that what I wrote recently is not very good, there is no passion, the last day of the May Day holiday, let's take a day off, and update it normally tomorrow.

After all, the author is not Zhang Yuan. He can explode the liver all day long and do not know that he is tired. He needs to rest normally ... (I also seem to become his QAQ)

Finally, there is a popular science article, an article written by an academician, I feel pretty good, you can check it out if you are interested.

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Opinions on the construction of a large collider in China

祚 庥 Researcher, Institute of Theoretical Physics, Chinese Academy of Sciences, Chinese Academy of Sciences

Written by He Ji (Researcher, Institute of Theoretical Physics, Chinese Academy of Sciences, Academician of Chinese Academy of Sciences)

Responsible Editor | Lu Haoran

1

的 The CEPC-SPPC project proposed by Director Wang Yifang and others from the Institute of High Energy Physics of the Chinese Academy of Sciences is not an innovative project. The overall design idea borrows from the LHC and enlarges it, and the project funding is also very large. The US SSC project has a planned energy of 20 TeV; Italy, that is, Europe had a larger project than the US SSC, with a higher planned energy. The energy of SPPC suggested by Wang Yifang is 70-100 TeV, which is actually similar to that of the latter, and the latter died without the opposition of many high-energy physicists in Europe.

The United States started a fierce debate for the SSC, and finally disputed in Congress, which was voted by Congress and finally rejected. Some people say that this is a victim of political disputes between the two parties, right! Regarding the decision of the SSC project, the person in charge of the financial affairs of the country believed that this project did not have much scientific value and was costly. It would affect the country's development capacity and was eventually abandoned. Of course, many high-energy physicists have expressed their support, but many high-energy physicists have also expressed their opposition and considered it a waste! In the end, Congress accepted the views of the opposing party and voted down.

I should also note that the thoroughness of the "veto" in the United States is surprising! The US government has invested US $ 2 billion, mainly to dig a large tunnel, and the cost of the tunnel in the plan accounts for about 10% of the total cost. Later, an additional $ 15-20 billion was required for eventual realization.

结果 But the result is that Congress would rather sacrifice the 2 billion dollars it should invest, and would no longer allow such unproductive investments. After the veto of the Congress, even the excavated excavations have been filled in, and "resurgence" is not allowed.

2

Why did the US Congress question the opinions of several experts and finally rejected the SSC project after the Congressional debate? There is also an important reason in academics: 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 "Great Desert of High Energy Physics" "theory.

"The Great Desert" theory holds that at least the energy must be raised to the Planck scale, which is equivalent to an energy of 10 ^ 16TeV, and new discoveries in high-energy physics are possible. Later, some high-energy physicists believed that this theory was not completely correct and should be revised. The method of correction is to introduce the concept of "supersymmetry", and think that with these supersymmetric particles, the energy standard will be reduced by many orders of magnitude, but still much higher than that proposed by SPPC! Later, several accelerators in the United States and Europe tried to find these supersymmetric particles, but found nothing. This also illustrates the rationality of the "Great Desert" theory from the side. Therefore, the U.S. Congress rejected the continued construction of the SSC project with an overwhelming number of votes.

Of course, the "missing" of supersymmetric particles immediately led to a major fundamental change of view, that is, the superstring theory elaborately produced by many particle physicists and mathematicians also "collapsed"! The so-called "downfall" here is aimed at the theory that superstring theory is meaningless in physics. However, it does not rule out its significance in mathematics.

But there is still a considerable part of theoretical physicists who do superstring theory and supersymmetric particles do not think that supersymmetric is dead, and they still insist. However, few people believe that this is a promising theory in particle physics, and they have announced that they will not change their careers. For example, Professor Li Miao who contributed to the theory of superstrings in the Institute of Theoretical Physics has now given up. In other words, superstring theory is no longer the mainstream of high-energy academics and particle sciences!

3

Combining the above two discussions, I can only think that the CEPC-SPPC solution 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 brought it to the Chinese government sell.

As for whether the Chinese government is willing to invest heavily in construction, it depends on how the Chinese government evaluates the matter.

We should also note that many of the people who sell the collider project are still American experts, such as academicians of the American Academy of Sciences, who said that this program has "many benefits." Of course, because the study of high-energy physics in China is far less advanced and developed than in the United States, it may be the "mouse" of us, without scientific foresight. However, there is still a question that makes me unable to understand: why such a good solution is not accepted by the US science and technology community? Why is such a good plan not to continue lobbying the US government? If the US government announces the launch of this "innovative" plan and hopes that China will also invest a lot of money to join the cooperation, I believe that it will definitely receive the full support of many scientists in the high-energy physics community in China!

4

One answer to our question is: This solution is still of 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 phrase "science knows no borders, and scientists have the motherland." We cannot agree to a plan that has little significance for the world's sciences, but will have "great significance" for the homeland of Chinese scientists. There are too many scientific problems to be solved in contemporary China, and many, many young people need to participate in this work. However, it is not possible that a few people from China or other countries in the world have entered the high-energy physics community, but they lack jobs, so they have come up with a scheme that is not very "effective" to accommodate these high-energy physics people!

The world is a whole. The economic and scientific development of countries in the contemporary world must follow the path of "integration" and "globalization". Recently, I study and study economics and political economics in my spare time. Many conclusions of economics should also apply to the development of world science.

We know that there is a law of diminishing marginal utility in economics, which can be applied to a wide range. For example, why has our economy increased from an average of 10% earlier to 6.9% today? The simplest explanation is diminishing marginal utility. The way to mitigate this effect is to rely on innovation. These basic principles are also necessarily applicable to the research of high-energy physics.

From the proposal proposed by Wang Yifang and others, this scheme is characterized by no revolutionary technological innovation at all, and it only develops towards "super large", so it must be applied to the law of diminishing marginal utility.

There is a technical difficulty in applying the law of diminishing marginal utility, that is, it is difficult to judge at what rate "marginal utility" is "decreasing", and how much will it "decrease" its "margin" in the future? In fact, recent experiments with LHC have given a judgement.

In the previous period, the LHC found a 750 GeV "resonant peak" in the 700-800 GeV energy range. The academic community is very excited, because it seems that high-energy physics can still make new discoveries toward the "high place". The theory of the "Great Desert" is inconsistent with reality! However, due to the insufficient number of experiments, it is not clear that this is a new particle. Therefore, some people advocate investing more operating time and costs in order to remove this "new particle". There are also a large number of theorists who think 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 the "Desert" theory still believe that this so-called "new particle" should be a statistical fluctuation, not a new particle.

As a result, further high-precision experiments show that the existence of "new particles" has not been confirmed! The "Great Desert" theory is still true in this energy zone. It should be noted that the energy of 750GeV is actually 6 times that of 125GeV of the Higgs particle called "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 LHC's energy zone has been reduced to "zero".

Now, in Wang Yifang's proposal, the maximum energy is only 7 times that of LHC. And if you follow this trend, how do you ensure that new particles are discovered, or other major new things? Not only that, the Geneva Center will soon further increase its energy to 20TeV and continue to engage in experimental work. But Geneva already has very large accelerators, and the West only needs to reinvest some money to realize marginal benefits. However, China has to restart the stove, which is only to increase the energy by 7 times, but to go back to the long journey that the Geneva Center LHC has gone through.

Or Wang Yifang's plan is by no means an equal competitor in Geneva.

The contribution of the Geneva Center's LHC to high-energy physics is huge. It has been running for 20 years. Four important particles have been discovered in succession, and the "standard model" is almost completely proved to be correct. There is only one small question left, namely whether the lepton number is "absolutely" conserved. However, the answer to this question does not require ultra-high-energy accelerators to study, but rather low- and medium-energy accelerators, such as the spallation neutron source, ADS and other projects already established by the Academy of Sciences.

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

Then, why is it necessary for China today to make a significant investment in this CEPC-SPPC, which is unlikely to produce significant results?

5

Of course, Director Wang Yifang has always emphasized that the positron-negative electron collider built by High Energy never overruns, and the fluctuation range will not exceed 5%. It should be said that this is a historical fact. As a witness of the Beijing Electron Positron, I have to tell some stories behind it.

The high-energy positron collider built by Xiu Gao Energy was a large-scale basic research project popularized by Comrade * based on the will of Premier Zhou after the Cultural Revolution. Its total construction cost was 220 million yuan. Since this is the first large-scale scientific research project specifically approved by the central government after the reform and opening up, the central government has come forward to say hello to all parties: this is not a piece of "Tang Monk Meat", and all ministries and commissions cannot take the opportunity to take a sip. This "hello" also spread to Hong Kong, which had not yet returned. The industry in Hong Kong stated that this is a project specifically approved by Comrade Xiaoping, and we must strongly support it. Even if we do not make money, we will try to ensure supply.

In order to ensure that the positron and electron colliders proceed as planned, the Central Committee also specially dispatched Comrade Hu Qiaomu's wife, Comrade Gu Yu, to preside over this task. When encountering difficulties, Comrade Gu Yu coordinated from it. For example, when the electron-positron collider started construction, nearby residents worried about radioactive contamination and opposed it. The environmental protection department therefore sent a division-level cadre to participate in the supervision. However, the cadre's professional knowledge reserve was insufficient, and he just blindly opposed it.

We asked her to come up with a corresponding "indicator", what kind of standard should be reached to pass, but she could not give a specific value. At that time, the leader of the High Energy Institute entrusted me to organize some young comrades to design protective devices for high-energy accelerators. Because the cadre sent by the environmental protection department was really "layman", he could not give a specific index, and we certainly suspected that she had "啃Meaning "a mouthful".

Therefore, Comrade Gu Yu went to Comrade Xiaoping to report the situation. In the end, Comrade Xiaoping decided that we were responsible.

Of course, our design was soon completed. Because this collider is a positron collider, it only emits x-rays and γ-rays, and its impact on the environment is smaller than the cosmic ray background.

The question is, in the present era, can Wang Yifang's "wishful thinking" be realized again? The conclusion should be: This is a plan that does not meet China's national conditions, and policy makers should not support it.

6

Director Wang Yifang also stated that ~ www.readwn.com ~ almost all opponents are experts outside the field of high energy physics. I don't think this is true.

We (the Institute of Theoretical Physics) also have a group of members of the High Energy Physics Society, and many of them are against it. In fact, there are some different opinions inside the high-energy institute, but because of the feelings of colleagues, I am embarrassed to make it public.

Previously, Professor Yang Zhenning published an article against the construction of a large collider in China. Some people also suggested that Mr. Yang has been away from the physics frontline for many years and deviated from the mainstream of physics. These questions are not correct. Although Professor Yang is old and has not rushed to the front line for many years, Mr. Yang's views on theoretical physics cannot be said to be outdated or deviate from the mainstream. Historically, Mr. Yang's Judgment cannot be said to be insignificant.

Recently, Director Wang Yifang also proposed that almost all high-energy experimental physicists are in favor of the construction of a large collider project in China. Opponents are all theoretical physicists. They have raised some questions about the profession of the opponents, including Professor Yang Zhenning. Nor is it an experimental physicist.

Well, then I also listed a scholar who can definitely be called a high-energy physics experimenter in the world, and is also the teacher of Professor Wang Yifang-Professor Ding Zhaozhong. Professor Ding asked me what research Wang Yifang is doing now, and I answered that he is also measuring neutrino oscillations in Daya Bay. In addition, he is working on some new schemes. Professor Ding asked what is the new plan? I said that he wanted to move a similar SSC scheme discussed in the United States to China. Professor Ding said immediately, why do you want to do this? Nothing interesting!

I'm sorry, I'm here to make Professor Ding Zhaozhong's opinion public. But I think this is enough proof that there are still some internationally renowned high-energy physics experimenters who do not support his scheme.