Chapter 267 The discovery that changed the physics building!
In the auditorium, there were many people in the audience expressing their opinions on the questions raised by Xu Chuan.
In the front row, Frank Wilczek reached out and poked Witten sitting next to him.
Witten cast a confused look.
"As to the question just now, what do you think is his answer?" Wilczek asked.
Witten thought for a while and said: "If I change the question to one word - "When facing the vast universe, what is the biggest 'difficult' problem that the human scientific community has encountered so far?"
"Then there may be many answers to this question."
"For example, the iron wall of the speed of light limits human beings' observation of the universe, such as how mass originates, or what is the cause of the expansion of space and time..."
"But 'When facing the vastness of the universe, what is the biggest puzzle that human science has encountered so far?'."
"I'm afraid there is only one answer to this."
Frank Wilczek: “Dark Matter?”
Edward Witten nodded.
Dark matter is by far the biggest mystery faced by all scientists in studying the universe.
One of the essential issues in scientific research is "material science".
What exactly is "dark matter and dark energy" that accounts for 96% of the total mass of the universe? From the time humans began to observe the universe until now, we still know nothing about it.
Even a mysterious black hole that can swallow light is still dazzling under the observation of modern science. In fact, today's science has enough ability to take pictures of it and present it to the public.
However, more than a hundred years have passed, and no one has been able to observe dark matter. It is a "mysterious existence" that is far more difficult to capture than black holes.
It is as mysterious as ever. Human beings cannot see it, nor know what it consists of, let alone its properties.
Except for the fact that there is indeed a substance unknown to mankind in the universe through the movement of celestial bodies, the phenomenon of Newtonian gravity, the gravitational lens effect, the formation of the large-scale structure of the universe, etc., there is no way to find it at all.
any trace of it.
After more than a century of research, modern scientists have discovered that humankind's understanding of dark matter has reached its "peak" from the moment it was discovered.
........
"In the data of the Alice detector, the 120um (rφ direction) beam z observation data of the antihelium-3 nucleus of the internal tracking system..."
On the podium, Xu Chuan raised a question and did not dwell on it too much, nor did he give his own answer. Instead, he started the core of the entire press conference.
Announce the results of this analysis of the Alice detector data.
Following his report, when the discovery of sterile neutrinos appeared on the projection screen along with the Dalitz diagram, and when the relationship between sterile neutrinos and dark matter was described, the commotion in the auditorium became more obvious.
Not only the media reporters who were busy taking pictures with cameras under the podium opened their mouths, but also the physicists who were invited to attend the lecture could not suppress their surprise.
Although many of these people had already learned about the content of this report meeting through the invitation letter in advance.
But when Xu Chuan stood on the podium to announce the news, it was still shocking.
........
"We have now completed the analysis of the 120um (rφ direction) beam z observation data of the antihelium-3 nucleus of the internal tracking system. Theoretically, the confidence level that there is a new type of particle that has not yet been discovered by the physics community has reached
3sigma."
"In the second half of this year, more particle collision experiments will be launched around this discovery to collect more data to confirm whether it is a sterile neutrino or another particle that we have never discovered."
"Now that the content of this press conference has been reported, it will be time for questions."
After the words fell, the media reporters in the front row raised their palms in unison.
If the stages weren't so far apart, they might have rushed up and stuffed the microphone into Xu Chuan's mouth.
On the podium, Xu Chuan stretched out his hand to signal the first media reporter to ask a question.
As a Chinese, the first media reporter he signaled was naturally the boss of the Chinese media, the reporter arranged by Yang Ma. However, this time it was not the acquaintance who came over, but another woman who was usually responsible for interviews in the field of physics.
reporter.
】
After all, this kind of press conference must involve some professional knowledge and questions. If the reporter who goes to interview doesn't understand anything, it will definitely not work.
After receiving Xu Chuan's signal, Yangma's reporter stood up excitedly and took the microphone from the staff.
"Professor Xu, you just mentioned sterile neutrinos and dark matter at the press conference. Can you please explain it in detail?"
Xu Chuan nodded and said, "Of course."
“Dark matter is an invisible substance that is theoretically proposed in physics and may exist in the universe. It may be the main component of matter in the universe, but it does not constitute anything we can currently see and observe.
Celestial bodies.”
"Combining observations of microwave background radiation anisotropy in the universe and the standard cosmological model (Λcdm model), we can determine that dark matter in the current observable universe accounts for 85% of the total mass of all matter and 26.8% of the total mass and energy of the universe."
"It is the main component of the universe and has not yet been discovered by us."
"The sterile neutrino is also a fundamental particle of the universe proposed in physics theory. It may be a fundamental particle that constitutes dark matter."
"Judging from the data analysis results of the 13tev energy level collision experiment of the Alice detector, it is very likely that there is a particle currently unknown to humans hidden in this area, and judging from various data, this unknown particle may be
Sterile neutrinos in theory.”
After the words fell, countless media reporters in the audience raised their hands again.
This chapter is not over yet, please click on the next page to continue reading! This time Xu Chuan just picked it casually, and the media reporter who was called was very excited.
"Professor Xu, you just mentioned a professional term in your report, 3sigma confidence. Can you explain what it means?"
Xu Chuan: "Sigma is a standard used by statistics to express the standard deviation, that is, the degree of dispersion of data. It is also called the "three times standard deviation method". It is a statistical criterion used to measure the performance of a specific sample combination of a specific test item.
normal range."
"You can understand that 3sigma means that the probability of this happening is more than 99.73%."
Hearing this, the crowd in the audience became commotion again.
Especially for media reporters who are not very familiar with the field of high-energy physics, the probability of 99.73% can be said to be very high. This probability is almost the same as if it happened.
"Professor Xu, does such a high probability mean that you have found dark matter?" A reporter from the audience quickly followed up and asked.
Xu Chuan shook his head and said: "I have never said this. In the world of physics, if you want to confirm the occurrence of something, or confirm the existence of a new particle, you need to have a confidence level of at least 5sigma.
.”
"The 5-sigma confidence level can be understood as 99.% of the observed results are real results. Only when this level of confidence is reached can the real existence be confirmed."
"So the next step is to conduct more experiments around this unknown new particle and collect more data to increase confidence."
After the words fell, another media reporter stood up: "Professor Xu, if I remember correctly, this collision experiment was conducted on September 28, 2018."
"On the day the collision experiment was launched, a 7.5-magnitude earthquake occurred in Sulawesi, Indonesia, killing more than 2,000 people and injuring more than 1,000 people. Are the two related? Is it caused by the operation of the LHC?
Earthquake in Sulawesi? Is this a warning from God?”
Upon hearing this question, Xu Chuan looked at the media reporter who asked the question. Sure enough, the person causing trouble was a foreign reporter, who was looking at him with a look of hatred.
"This is something without any basis. In fact, the operation of LHC will not cause any damage to the earth's ecological environment, let alone cause natural disasters such as earthquakes..."
At press conferences, reporters from such media ask all kinds of weird questions every time.
There is also a group of people who have always believed that the operation of the LHC will bring disaster to the earth, so every year a large number of people gather to protest to stop the LHC experiment.
In this regard, Xu Chuan could only say that the popularity of nine-year compulsory education abroad is really low, and such people should have their brains cured.
But he can't say this at a press conference, and he has to be careful with the words he uses to answer this question. Once reporters from these media catch him giving an answer that can be taken out of context, he will really fall into a pit that is either shit or shit.
.........
The atmosphere in the auditorium was quite lively.
In addition to a small number of media raising some weird questions, more media reporters are focusing on things like sterile neutrinos, dark matter, and the universe.
No way, this discovery is really amazing.
Sterile neutrinos, dark matter, dark energy...
If such a particle really exists in the 13tev ultra-high energy level collision experiment data, in a sense, this will be a disruptive discovery.
Many people present thought of the "neutrino superluminal event" nearly ten years ago. At that time, the neutrino oscillating latex track (opera) collaboration team from Italy announced that it had discovered a neutrino in a neutrino experiment.
"Neutrinos that travel faster than the speed of light".
This result will almost directly break the special theory of relativity created by Einstein in the last century, and will almost subvert the entire world of physics.
Fortunately, it was later confirmed that superluminal neutrinos did not exist. It was just a problem caused by a faulty fiber optic cable that caused this embarrassing incident.
And this time, if the sterile neutrino, a particle related to dark matter, is confirmed, although it will not directly subvert the entire world of physics, it will bring a broader future to mankind.
.........
In this Internet era, the speed of message transmission is undoubtedly very fast.
In the afternoon after the press conference was held, various media outlets quickly conveyed the contents of the press conference.
And the titles taken out are also more amazing than the last, and each one is more eye-catching than the last.
"Shocked! The youngest Nobel Prize winner in history confirmed the existence of dark matter!"
"Dark matter, which accounts for more than 85% of the total mass of the universe, has been discovered, and it looks like this!"
"The sterile neutrino! A particle that exceeds the standard model building is also a bomb thrown into high-energy physics. The building of physics is about to collapse!"
"......."
One headline after another quickly detonated the entire Internet, attracting countless fans.
[Holy shit! Dark matter has been discovered? 】
[I didn’t say it, I just said that a new particle may have been discovered. It may be a sterile neutrino, which may be a part of dark matter. Pay attention! There are three possibilities here, so it is fundamentally uncertain. 】
[Dark matter cannot be discovered, and nothing that can be observed is dark matter!]
[It’s all conjecture. It can neither be confirmed nor falsified. You can only listen to it while eating and entertain yourself. But it’s obviously a higher standard because no one can refute you. The reason is that it can neither be confirmed nor falsified.
.]
[When did Sichuan God become such an uncertain party? Woohoo, my Sichuan God.]
[High-energy physics is like this. Before any new phenomenon or new particle is finally confirmed, we can only say that it may exist, but the 3sigma confidence level is indeed a bit low. 】
This chapter is not finished yet, please click on the next page to continue reading the exciting content! [As expected of the God of Sichuan! This is news that shocked the world.]
[The probability of more than 99.73% is still low. When I threw the dice for the multiple-choice question in the college entrance examination, the probability of being selected was one-half, which was already very high!]
[Laughing and crying, how can it be compared like this? Your college entrance examination is not important to human science at all, and this top science must be completely certain. If you are wrong, it will affect your college entrance examination. 】
【So what exactly is dark matter?】
[I don’t know! If you ask me who to ask, I guess even God of Sichuan doesn’t know what dark matter is.]
........
On the Internet, the related popularity is rising rapidly.
Of course, this also has something to do with Xu Chuan. Since he won the Nobel Prize, many people have been paying attention to him and want to know what he is researching.
With its own popularity, and the fact that the term dark matter carries all kinds of things that can be discussed, the discussion on the Internet is quite heated.
But this has no impact on either Xu Chuan or Lai Yan.
After the press conference, NTU invited various Nobel Prize winners in physics to hold a report or lecture.
At this report meeting, Xu Chuan gave a more detailed introduction to the discovery of sterile neutrinos than the press conference, which will attract more physicists to devote their energy to this field.
He is not worried that others will discover or analyze and confirm the existence of sterile neutrinos in advance. He is confident enough about this.
But at the same time, there are countless secrets hidden in the field of high-energy physics. Sterile neutrinos are only part of dark matter, and research on dark matter requires more physicists to work together.
Relying on his own strength alone is far from enough.
However, what Xu Chuan did not expect was that his press conference not only attracted the attention of the majority of netizens, but also attracted the attention of higher-ups.
After the report meeting, an unexpected red phone call came directly to his mobile phone.