Chapter 253 Dark Matter

From the moment humans looked up at the sky, their imagination of the sky, the universe, and the stars has never stopped.

The sun, the moon, the stars, everything looks so beautiful and mysterious.

After entering modern society, scientists began to use various instruments and equipment to observe and study the stars in the universe.

After a long time, they discovered that there may be a huge problem in the universe we live in.

That is, all the substances we are familiar with in daily life, such as trees, rocks, atoms, planets, stars, and galaxies, add up to less than 5% of the weight of the entire universe.

And what is the remaining 95%, neither visible nor known.

In subsequent research, scientists conducted a lot of tracking and analysis on this 95% of matter.

Finally, through various physical formulas and observational data, it was determined that there is an invisible substance in our universe that accounts for more than 95% of the total mass.

At that time, Professor Fritz Zwicky, the first astronomer who speculated on the discovery of this substance, named it ‘Dark matter’, which is the origin of dark matter.

In subsequent research, scientists found that Dark matter is actually divided into two types, one is the dark matter that was first proposed, and the other is dark energy.

Among them, dark matter accounts for 25% of the entire universe, while dark energy accounts for more than 70% of the entire universe.

The total mass of these two together accounts for more than 95% of the entire universe.

The remaining less than 5% of matter has formed everything we can observe today.

However, to date, we still cannot specifically observe 95% of dark matter and dark energy.

The research on them is still based on various speculations and observations of those abnormal cosmic phenomena.

For example, the movement of celestial bodies, the phenomenon of Newton's universal gravitation, the gravitational lens effect, the formation of large-scale structures in the universe, observations such as microwave background radiation, etc.

These cosmic phenomena indicate that dark matter and dark energy may exist in large quantities in galaxies, star clusters and the universe, and their mass is far greater than the sum of the masses of all visible celestial bodies in the universe.

Combined with the observation of anisotropy of microwave background radiation in the universe and the standard cosmological model (ΛCDM model), it can be determined that dark matter in the universe accounts for 85% of the total mass of all matter and 26.8% of the total mass-energy of the universe.

Regarding the study of dark matter, a widely accepted theory holds that dark matter is composed of "weakly interacting massive particles" (WIMPs), whose mass and interaction strength are near the electroweak scale, and the observed residual abundance is obtained through the thermal decoupling process during the expansion of the universe.

In addition, there are also hypotheses that dark matter is composed of other types of particles, such as axions, sterile neutrinos, and other hypothetical particles.

In his previous life, Xu Chuan observed two types of matter, axions and sterile neutrinos, which indirectly proved the existence of dark matter.

If it were not for the Nobel Prize regulations, he would have won the Nobel Prize in Physics in 2018 in his previous life directly for this discovery.

According to the Nobel Prize awarding principles, the medal will not be awarded to the discoverer of particles or some unknown phenomenon in existing theories, nor will it be awarded to researchers operating hadron colliders.

Even if the results are sensational, they will only be awarded to the proposer or improver of this theory.

Because in the general view of the academic community, the work of the first two is important, but not decisively important.

The latter's work is decisive.

For example, in 2012, CERN detected the Higgs boson, and in 2013, the Nobel Prize in Physics was awarded to Peter Higgs and Francois Vanguard, the proposers of the Higgs boson theory.

As for the CERN researchers who participated in the experiment, although everyone has made contributions, unfortunately, the Nobel Prize has nothing to do with them.

His mentor Edward Witten is actually a famous scholar of this type.

He proposed the M theory and a series of perfect theories. If these theories are verified to be true, then he will undoubtedly win the Nobel Prize.

But it is also quite regrettable that it is still unknown how long it will take to verify his theory.

Just like the Higgs boson was proposed in the 1960s, it took nearly 60 years for Higgs and Francois Vanguard, who proposed the theory, to win the Nobel Prize in 2013.

If Witten wants to win the Nobel Prize with his M theory, he may have to wait until he and Higgs become old men in their 90s to achieve it.

Therefore, Xu Chuan could not win the Nobel Prize for discovering the axion and sterile neutrino.

However, if he improves his previous method for calculating the "optimal search decay channel for the Yukawa coupling of the Higgs particle and the third-generation heavy quark" and spreads it to most particles, he may have a chance to win another Nobel Prize in Physics.

A mathematical model or method that can greatly save scientific research funds, save a lot of manpower and material resources, accelerate the search for new particles, and replace old methods at night. It is as important to high-energy physics and particle physics as the expanded application of the Xu-Weyl-Berry theorem is to The world of astronomy is as important as the world of astrophysics.

But I'm afraid he hasn't had time to do this recently.

On the one hand, he has a project in hand, and on the other hand, he has to get the discovery of sterile neutrinos first this year.

After all, this is his own scientific research result, and there is no reason for others to take it away.

Although the Nobel Prize is the highest honor, it is not that he has never won it.

Sterile neutrinos are related to the discovery of dark matter, which in Xu Chuan's opinion is more important than the Nobel Prize.

It's just that he can't go abroad at the moment, so he can only find a way to see if he can get experimental data from CERN and analyze and process it domestically.

Originally, it was a good opportunity for China to join CERN and become a member country, but unfortunately, the personnel currently arranged by China are mainly concentrated on the two major detectors, LHCb and ATLAS.

As for ATLCE, no personnel were arranged to go there.

This caused him a lot of trouble in finding the data.

Fortunately, his mentor is Witten, and his current identity is completely different from before. The reputation of a Nobel Prize winner in physics can help a lot.

After all, even in CERN, the holy land of physics, there are not many Nobel Prize winners, just a handful.

If a Nobel Prize winner actively participates in the analysis of experimental data, both the team responsible for the ATLCE detector and CERN will welcome it.

Even if he didn't go there in person.

After chatting with Lin Feng about the physics world and CERN cutting-edge information, Xu Chuan returned to his villa.

The annual person of the year event here at Nanda has been completed, and he has nothing to do with the rest.

Picking up the phone, Xu Chuan called Edward Witten.

"Hello, Xu Chuan." Edward Witten's voice came over from the other end.

"Tutor, did you participate in the high-energy collision experiment of CERN's ATLCE detector some time ago? Or did anyone you know participate in it?" Xu Chuan asked.

Witten thought for a while and then replied: "ATLCE detector? Let me think about it, I am not processing the data there. The high-energy collision experiment some time ago seems to have processed the experimental data from the California Institute of Technology and the University of St. Andrews." The team is handling it.”

"Why, are you interested in the experimental data of ATLCE?"

Xu Chuan nodded and said: "Well, I heard that the LHC set a collision experiment at the 13Tev energy level some time ago. I am very interested in the experimental data at this energy level."

Witten smiled and said: "Then you can come to Geneva. You are an official researcher anyway, and CERN will welcome you at any time."

After a pause, he continued: "I believe that the teams at Caltech and St. Andrews University will not refuse the addition of a Nobel Prize winner."

Xu Chuan shook his head and sighed: "It's a pity that I have something to do now and can't go there. If possible, I would like to have a copy of the original data of the collision experiment."

Witten pondered for a moment and said, "Okay, let me ask for you and see if I can get a copy of the experimental data."

Shrugging, he continued: "Although the time for making it public has not come yet, the teams at Caltech and St. Andrews University don't seem to have analyzed anything useful yet."

"Maybe I can make new discoveries in your hands?"

"After all, no one is better at analyzing these collision data through mathematics than you."

Xu Chuan smiled and said, "Then I'll trouble my mentor."

Witten waved his hand indifferently and said: "It's a small matter, I hope I can find something new."

"After all, in today's physics world, nothing new has been discovered for a long time."

After entrusting the acquisition of high-energy collision experiment data to his mentor Edward Witten, Xu Chuan returned to the Institute of Nuclear Energy and continued the second phase of semiconductor material research and development.

Less than two days later, Witten returned the phone call.

"Hey, Xu Chuan, I applied to CERN for the collision experiment data you want, and the analysis teams from Caltech and the University of St. Andrews also agreed."

"The experimental data is being packaged and processed now. It will take about two or three days. How will it be sent to you after it is processed?"

Edward Witten's voice came through the phone. Xu Chuan thought for a moment and said, "Please pass it on to my alma mater, Nanjing University. I will go and talk to them and arrange to connect with CERN."

"Okay, I happen to be having a meeting at CERN these two days, so I'll keep an eye on you first."

Xu Chuan said with shame: "It's too troublesome for you, mentor. It's not a big deal. Just find someone to connect with me."

Isn't it a waste of talent for a Fields Medal-level boss to help him monitor and transmit data? For such a trivial matter, just find an intern or staff member.

Witten smiled and said: "It's okay. I hope you can find something new in the data of this collision experiment."

After hanging up the call, Xu Chuan turned around and went to Nanda to borrow the supercomputing center of Nanda.

NTU also has a supercomputer and a supercomputing center, which were established just a few years ago.

NTU's high-performance computing project was officially launched in 2009 and officially established in March 2010.

Nanjing University's School of Atmospheric Sciences, School of Physics, School of Earth Sciences and Engineering, School of Chemistry and Chemical Engineering, School of Astronomy and Space Sciences and more than ten other schools and departments are the recipients of services provided by the High Performance Computing Center.

The theoretical computing peak reached 34 trillion floating-point operations per second, ranking seventh in the national computer TOP100 ranking and 203rd in the world computer TOP500 ranking.

In 2018, the supercomputing center of Nanjing University was not outdated and its performance was still good.

At least there was no problem in processing the experimental data sent from CERN.

For his request, Nanjing University agreed without any hesitation, and most of the non-urgent tasks of the supercomputing center were postponed for a whole month.

Although the Nanjing University High Performance Computing Center has been continuously performing high-speed calculations at full capacity, and the daily tasks are very heavy, postponing most of the tasks for half a month means that many people's matters will be affected.

But whether it is a request from a Nobel Prize winner or borrowing the Nanjing University supercomputing center to get CERN data, it is a very meaningful thing for Nanjing University.

The Department of Physics at Nanjing University is very strong, ranking at least in the top three in China. It has always been a cooperative unit of CERN, and many students are sent to CERN every year.

Whether they are brought there by professors or applied by themselves.

It is very good to be able to participate in the processing of experimental data in CERN, the holy land of physics, even if it is hard labor, to feel the atmosphere there.

There are too many masters there. If you are really interested in academics, I believe you will not miss such an opportunity.

And Xu Chuan got the experimental data to be processed at the supercomputing center of Nanjing University, which will definitely require a group of professors and students to help. For Nanjing University, it will help to cultivate more talents and apply for more exchanges with CERN next year.

"Then teacher, I'll trouble you with the early experimental data analysis."

In Chen Zhengping's office, Xu Chuan said with an embarrassed look.

After Nanjing University and CERN were connected, Witten arranged for someone to send the experimental data of the ATLCE detector.

The data are all raw data that have not been analyzed and need to be processed.

But it is obvious that he has no time now. The second phase of semiconductor material research and development of the nuclear energy project has entered a critical stage, and he can't spare time to do other things.

So we can only trouble Chen Zhengping and NTU to send a group of doctoral students to help process the preliminary experimental data.

Although Caltech and St Andrews University have analyzed these data for a long time, it is obvious that they will not give him the data they analyzed.

It is good to agree to let him get a copy of the original data for use. After all, this is the project they applied for, and it will take a long time before it is fully disclosed.

In the office, Chen Zhengping smiled and said: "It's nothing. It's still a good thing for NTU students. After all, not everyone has the opportunity to practice at CERN."

"Your complete copy of the original data is enough for them to experience the experience of working at CERN in China."