Chapter 464: Some casual words solved the doubts~ (8.4K)
Students who have done particle collision experiments should all know this.
When you enter the laboratory on your first day, your instructor will definitely tell you this:
"In the field of particle physics, a single case report has no reference value."
Tell the truth.
This sentence does apply to most situations, and an isolated example does not make any sense in many cases.
However, in a few cases, it may not be accurate.
The most representative one is the impact experiment conducted by Makoto Kobayashi and others. Everything is 0, and the curve is so flat that it can no longer be flat.
Even if there is only one case statistics, it is enough to explain a lot of problems.
Another example.
At this moment, in front of Xu Yun and others was the case list numbered 234491835.
The protrusions on this list of examples are extremely astonishing. They are as good as the small umbrellas that readers have when they wake up in the morning, and they are about 20 centimeters away.
Don’t talk about people in the industry.
Even Chen Shanshan and the audience watching the live broadcast outside the venue can see that this signal is definitely not an accident.
In other words.
Among the magnitudes calculated by the Academy of Sciences team, there is indeed an unknown particle.
However, as a senior fan of AC Milan, Academician Pan knows one thing very well.
That is, before the real hammer comes down, no matter what, you must endure not to open the champagne.
After all, let’s not talk about the far ones, let’s talk about the near ones:
The 11.4514GeV particles calculated by Atsushi Suzuki and others are capable of overturning.
So Academician Pan calmed down, forced himself to calm down, and said to the somewhat excited Carlo Rubbia:
"Mr. Rubia, please calm down. What we need to do now is to collect and summarize the cases first, completely summarize the relevant attributes of the particles and determine the true attributes of the particles. Ten million
"We can't let the old thing of 750GeV happen again."
750 GeV.
The second half of Academician Pan's words hit Carlo Rubbia's heart like a book of Boruto, causing his whole body to tremble.
The excitement that originally emerged has also subsided by most of it.
Theoretical physicists are all cursing CERN's original operation, but at that time CERN actually thought that they had discovered a new particle, and internally it was said that they had even thought of a name for the particle.
Who knew that such a stable particle would actually overturn, and CERN was scolded and has not been forgiven to this day.
So after hearing what Academician Pan said, Carlo Rubbia immediately calmed down.
Then he thought for a moment, took out his cell phone, and dialed a number.
After a while.
The call is connected.
"Hello, Mr. Rubia."
Carlo Rubbia moved the phone away and pressed the speakerphone button at the same time:
"Pop, how many cases are there now?"
There was a slight tapping sound on the keyboard from the other end of the phone:
"There are more than 2.33 billion messy cases - including meaningless cases."
Carlo Rubbia nodded.
The number of cases reported by my assistant sounds scary, but it is actually quite normal.
Just like two high-speed cars accidentally collided together, if even a few millimeters of fragments were counted, then there would be hundreds, thousands, or even more.
These examples are true to their meaning, and many of them are meaningless and worthless fragments.
Then Carlo Rubbia paused and continued:
"How many cases are there after optimization?"
"8.79 million copies."
"What about the one with the same fluctuation signal as 234491835?"
“There were 219 major incidents and 548 signal bulges.”
Carlo Rubbia's breathing suddenly accelerated a bit.
Unlike meaningless cases.
The so-called big event does not refer to the sputtering of various small particles after the collision, but the initial event of the collision of two lead ions.
To use the head-on collision example above, it is the collision of two cars.
In general.
During a large collision, the total number of colliding particles emitted is about 10 to the 14th power.
Among them, the 'big cases', that is, the total number of 'car accidents' in which collisions occurred, is probably between 2 million and 5 million times - of course, this number varies depending on the project, but it can only be said that this is a relatively common range. .
Among large events of this magnitude, the number of abnormally large events that can prove the existence of a certain particle is generally
Starting around 40.
That is to say, among 2 million collisions, 40 major events can show fluctuation signals, which can basically determine the existence of this particle.
By the way.
CERN originally proved that the number of large cases of so-called 750GeV particles was.
Two servings.
Then Carlo Rubbia glanced at Academician Pan beside him, and the two nodded at the same time with great understanding.
Just listen to Carlo Rubbia say to the phone again:
"Pop, please transmit those 219 major incidents to the information backend of the Chinese Academy of Sciences immediately, as quickly as possible!"
"I understand, Mr. Rubia!"
After hanging up the phone.
Carlo Rubbia put his cell phone back into his pocket, took off his eyes, and said to Academician Pan in a serious and thoughtful voice:
"Pan, the rest will be left to you."
Academician Pan nodded towards him, turned his ear back again extremely ably, and ordered:
"Xiao Chen, get ready and enter CERN's information packets into the background as soon as possible!"
"Understood!"
After saying these words.
Academician Pan returned to the front row with Hou Xingyuan and Carlo Rubbia.
He first ignored Suzuki Atsushi, who was gasping for breath, and then said hello to Mr. Yang and Witten, who looked expectant.
Then he waited with peace of mind.
Another moment passed.
Academician Pan heard a reply:
"Academician Pan, all the information has been entered!"
Academician Pan snorted, walked behind Xu Yun, blocked everyone's view of Xu Yun as a tool, and asked in a low voice:
"How is it? Has the report been verified?"
"Yes, we used the supercomputer 'Dawn' to conduct an emergency analysis. Although the specific properties require subsequent analysis, we can be sure that this is a new particle and not a statistical fluctuation like CERN."
When Academician Pan heard this, he immediately felt certain.
That last sentence is enough.
Then he thanked Erhui across from him, patted Xu Yun's shoulders hard several times, and strode towards
Podium.
See this situation.
The somewhat solemn atmosphere at the scene was once again solemn.
Nervous
Looking forward
Delight
Disgust
Muran
All eyes focused on Academician Pan at the same time.
After arriving at the podium.
Academician Pan first calibrated the microphone, looked around, and then said slowly and clearly:
"Dear colleagues at the scene, media guests, and external audience friends, everyone has been waiting for a long time."
“Not long ago, the Academy’s backend received first-hand reports from CERN on a total of 219 major cases.”
"Of course, the first thing to emphasize is that we don't know whether these 219 major incidents can prove the existence of the particles."
"Maybe there is, maybe there is not, no one can know the truth."
Hear this.
Xu Yun in the audience couldn't help but glance at Academician Pan, who had a look on his face that said, "We really don't know anything."
"."
As expected of me, Rabbit.
Then Academician Pan paused and continued:
"Next, our backend staff will synchronize these 219 major incident reports to the data terminals in front of you, and professionals will conduct report analysis and judgment."
"Attendees whose main major is particle physics will receive an additional voting qualification."
"That is, if you think these reports are sufficient to prove the existence of particles, please vote 'yes', if not, please vote 'no' - of course, you can also choose to abstain."
"As for non-particle physics majors, participants are not eligible to vote, but they can still check the analysis case reports at will."
As soon as Academician Pan said this.
The audience was only silent for a few seconds, and then there was a low sound of discussion.
Many scholars who were a little tired quickly sat up straight, and some quickly flipped through their briefcases to find paper and pens.
Academician Pan's words directly touched their hearts.
After all, as the top bosses in the industry, they have been watching the show in the audience for so long. It is impossible for them not to feel itchy.
But the problem is that the previous process of calculating particle Fermi surface data was very difficult, and even Higgs and others needed assistants to help.
Although these big guys at the table were moved, they were really powerless.
But it's different now.
Facing the data that has been generated, they do not need to perform large-scale calculations. What is tested is their long-term ability to analyze the data.
This is their strength, just like riding a bicycle, and they may never forget it in their lifetime.
Of course.
Some people are eager to try it, and naturally some people are a little dissatisfied with the Academy's approach.
"Why?"
On the tenth row of seats.
Christine was putting her hands on her hips and looking angrily at Academician Pan on the stage:
"Why do you have to have the right to vote only if you are engaged in particle physics? Is this discriminating against cosmology and statistical physics?!"
Lu Chaoyang beside her smiled and explained:
"Ms. Christine, after all, this vote is of great importance. Statistical physics is different from particle physics in this situation."
"Although your knowledge of particle physics is equally profound, not everyone is the same as you"
Lu Chaoyang's words were not entirely compliments.
During the previous particle calculation process, he had discovered that this girl was indeed an all-rounder and had deep research in particle physics.
However, the current occasion is obviously not suitable to give Christine the green light alone, so I can only feel a little wronged to this filial daughter.
As an assistant researcher at Harvard University, it was naturally not difficult for Christine to understand this truth, so she simply complained:
"Forget it, I hope I can have a chance in the future. Why are the documents from your academy of sciences transmitted so slowly? Huh? Here they are!"
The words just fell.
A file icon instantly appeared on the data terminal in front of Christine and Lu Chaoyang that was originally watching the live broadcast.
Seeing this, Christine couldn't wait to sit back in her seat and quickly clicked on the file.
Although for a scientific researcher, there are more opportunities to come into contact with paper reports on weekdays.
However, computer equipment is very popular these days, and many experimental data are directly viewed on the computer, so it is not difficult to adapt to the current data terminals.
Then quickly.
Kristine put on the noise-cancelling earmuffs and began to check the relevant data.
[Particle Detection Report] This word may be a bit unpopular in 2023. You can almost see this thing in novels with black science fiction.
But there are probably very few people who know what the content of this kind of report is and how to read it.
For example, a very simple question.
At present, all particles are invisible to the naked eye, and their trajectories can only be simulated afterward through a cloud chamber. So how do physicists know what particles they have captured?
Is it an image?
Or some kind of probe test?
NO.
The answer is the reported value.
For example, the simplest numerical value is the intrinsic property of the particle:
Mass, charge, spin.
On the basis of the above three, the report will also add a special column:
CP properties.
In addition, data such as the cross section of the generation channel and the branch ratio of the decay channel can be refined through interaction.
Take the Higgs particle discovered by CERN in 2012 as an example.
The Higgs particle predicted by the Standard Model is a neutral particle with spin 0 and CP ++.
It interacts directly with W and Z particles and fermions with mass, and the intensity of the interaction is proportional to the mass of the particle.
This can be seen in the original CERN report.
They found the Higgs particle from a two-photon final state, which means that the new particle can decay into two photons.
Students who have taken junior high school physics should all know this knowledge:
Photons have no charge.
So from conservation of charge we know that the particle is also uncharged.
also.
Since the final state is two bosons, we can also know that the new particle must be a boson.
Then according to the conclusion of the Landau-Young theorem, it can be seen that a particle with spin 1 cannot decay into two photons.
Therefore, the spin of the new particle can only be 0, 2, 3...
Next, CERN measured the cross-section and angular distribution of the new particles decaying into WW and ZZ and fitted them, and found that everything was in good agreement with [CP++ particles with spin 0].
Finally, CERN measured new particles to the final states of bb, mumu, and tautau as well as the joint production of new particles and tt, and found that they were also in good agreement with the assumptions of the standard model.
Therefore we can draw the conclusion:
This new particle is the Higgs particle.
This is the real basis for determining which model a particle can benchmark against.
Useless knowledge has been added.JPG.
So at this time, these experts are comparing their knowledge of particle models, not other abilities such as computing power.
"Spin 1/2 is the same as the value calculated by Professor Witten and others before. It satisfies the Pauli Exclusion Principle and belongs to the standard energy localized field configuration"
"The LL3 process has the largest cross-section and is consistent with the fourth-order Feynman diagram oscillation."
"Quick, quack, quack."
The results were watched.
Lu Chaoyang suddenly frowned.
His eyes rested on a report numbered 43967777, with a trace of doubt in his eyes.
This is a large example of band signal data, recording a small bulge in the final state of tautau+gamma.
There are hundreds of similar bulges in the entire report - as mentioned before, it is rare for CERN to conduct such a high-level experiment, and it must collect a variety of data.
But the current bulge
But it's a little strange.
As everyone knows.
In quantum theory, Hilbert space can be decomposed into the direct sum of Bose state and Fermi state subspaces:
H=H++H.
If the fermion parity operator is defined as (1)F, and F is the number of fermions, this is its invariant subspace decomposition.
The eigenvalue +1 corresponds to the Bose state, and the eigenvalue 1 corresponds to the Fermi state.
The spin of Pluto particles is 1/2, which means they are fermions.
But now the eigenvalue of the tautau+gamma terminal bulge is +1.
This is a little strange
And just when Lu Chaoyang frowned and thought.
Suddenly there was a whisper in his ear - due to personal habits, he did not wear earmuffs:
"Hey, what's going on with this data?"
Lu Chaoyang subconsciously turned his head and found that Kristen was holding a pen in her mouth, frowning and staring at the screen in front of her.
Seeing Lu Chaoyang looking towards her, the girl turned the screen towards Lu Chaoyang:
"Hey, Lu, come take a look at this."
Lu Chaoyang poked his head towards her.
She discovered that the report on her screen was not the same one she was looking at, but document number 2200433.
As a result, after just two glances, Lu Chaoyang couldn't help but raise his eyebrows:
"This is."
It was completely different from the content of the report in his hand.
The eigenvalues of the report in Christine's hands are normal, but it is an expression of a scalar field!
Mentioned before.
Scalar fields cannot describe fermions, only spinor fields can describe the spin of fermions. (See Chapter 455)
This is very strange
Then Lu Chaoyang thought for a while and handed his data terminal to Christine:
"Ms. Christine, to tell you the truth, I also found an anomaly report here."
Christine raised her head and looked at him, then took the terminal and looked at it.
After a while.
Kristine's voice sounded in Lu Chaoyang's ears again, but this time, this carefree girl's tone was unusually nervous:
"Lu, do you still remember your previous guess?"
Lu Chaoyang was stunned for a moment.
After a few seconds.
He suddenly thought of something and tapped the math paper on the table with his index finger:
"Are you talking about the previous Riddler's ahem, the theoretical model that can be established in the 1TeV range?"
Kristine nodded heavily:
"Yes, if that theory is applied, there seems to be room for explanation of this phenomenon."
Lu Chaoyang's expression changed for a while. He looked down at the report several times again, and finally frowned and sighed:
". It seems that it is not enough. The energy scale is still a little behind. No, it should be said that it is a lot worse."
"For that theoretical model to be able to explain this phenomenon, other new evidence is needed."
"Otherwise, these big guys here would have expressed their opinions a long time ago - do you think you and I are the only smart people?"
After hearing this, Kristine opened the calculation paper again, picked up a pen and calculated on it for a while, and then said quietly:
"Indeed, the difference is at least two orders of magnitude."
Just as Lu Chaoyang said.
There are not a few scholars who have discovered this kind of anomaly. After all, there were thousands of people present, including twenty Nobel Prize winners.
Perhaps no one will be able to completely figure out the causes and consequences of the data anomaly for a while, but it is definitely not just one or two people who discovered the anomaly and came up with an idea.
Of course.
There are also some scholars who have not considered it so deeply.
After confirming that the data was normal, someone quickly pressed the voting button representing the presence of particles.
First row.
Looking at the progress bar showing 14 confirmed votes and 0 opposed votes displayed on the screen, Academician Pan's expression still looked very calm.
After all, in this situation, there is no point in denying the situation. On the contrary, it will affect your reputation.
At this moment.
What Academician Pan, Witten and others really care about are the problems shown in a few reports.
After all, the process of proving whether a particle exists is complicated. It doesn't just mean that it is captured.
The spin and CP properties of the particles, what kind of particles they belong to, and what their constituent states are. All these must be explored.
"Strange"
Witten crossed his left hand across his chest, put his right thumb on his chin, and frowned:
"We have received 39 pieces of abnormal data. Although it has no impact on the conclusion that the particles exist, this abnormal situation cannot be ignored."
"What is going on here?"
Beside him, Academician Pan, Zhou Shaoping and Mr. Yang also looked a little confused at this time.
Due to the real-time transmission of signals, the supercomputing background of the Academy of Science and Technology could only prioritize the big issue of verifying the existence of particles. As for small anomalies such as bulges, it certainly could not cover everything.
So even Academician Pan and Hou Xingyuan, or even Carlo Rubbia, the head of CERN, were not aware of this situation in advance.
After a while.
Hutft's eyes moved slightly, he slowly raised his hand and said:
"Everyone, I have an idea. Could this particle be similar to the X17 particle? - I mean a model rather than an example."
Witten was stunned:
"X17 particles?"
X17 particles.
This is a very topical particle.
This is an example announced by the Atomki project team of the Hungarian Academy of Sciences a few years ago.
At that time, they claimed that the new particles discovered during the transition of helium atoms and the decay of beryllium-8 had properties close to a predicted type of boson.
As everyone knows.
New bosons represent new interactions, so many articles at that time hyped that humans suspected of discovering a fifth force.
But actually.
In subsequent verifications by multiple parties, no institution has reproduced this phenomenon.
At the same time, the Atomki project team has announced many shocking "major discoveries" before.
For example, in 2001 they claimed to have discovered a new particle of 9eV, in 2005 they claimed to have discovered the abnormal behavior of multiple particles caused by new particles, in 2008 they claimed to have discovered a new particle of 12eV megaelectronvolts, etc.
However, none of these findings have been replicated a second time so far.
Therefore, the Atomki project team is also jokingly called the Internet celebrity project team in the industry.
But on the other hand.
Although the case of the X17 particle is probably false, its model is still relatively useful for reference.
Its manifestation is the excited state of the electron even element, and its mass is between the ground state of the electron even element and the π0 meson.
Theoretically, when the electron momentum of the electron element reaches a certain mutation state, it may indeed cause some abnormal data.
But soon.
Higgs, who had studied particle models the most at the scene, shook his head:
"Unlikely, Gerald, if it is a similar principle to the X17 particle, then it must decay first to produce a positron-electron pair."
"If positrons are generated, then some signs must be seen in the 1.022MeV range, but it is a pity."
As he spoke, Higgs pointed to a blank space in the report:
"There is no positron-generated signal here."
Tehuft stepped forward and looked at it for a while, then nodded silently.
Higgs is right.
That is to say
The model of the X17 particle is not suitable for the current situation.
So what is this exception?
Just when the atmosphere at the scene was a little gloomy.
A voice suddenly sounded in Higgs's ears:
"Ah, it's so strange." Note:
The doctor asked me to be hospitalized, which was hard to bear, but actually I felt fine
(End of chapter)