Chapter 465 The true identity of the particles! (Part 1)
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First row area.
I heard this sudden sound of ‘ah lie lie’.
All the big guys who were thinking about the problem raised their heads and turned to look at the person who made the sound.
I only see this moment.
A few meters away from them in the open space.
Xu Yun was holding a report in his hand, tilting his head slightly with an innocent expression on his face.
However, Academician Pan, who knew his student's character well, instantly realized something. He gently adjusted his glasses and looked at Xu Yun:
"Xiao Xu, have you discovered anything?"
The last time Xu Yun spoke, Academician Pan was a little worried that his identity was inappropriate.
But after Xu Yun assisted Zhou Shaoping. No, to be more precise, it was Xu Yun who relied on his own ability to keenly realize that there was a problem with the limited-angle vector rotation and it was successfully verified.
He already has the right to express his views from the front row - at least in this meeting.
Therefore, Academician Pan did not take any protective action this time, but directly questioned Xu Yun.
Then Xu Yun winked at Academician Pan, came to Academician Pan, and handed the document in his hand to him:
"Teacher, look at this data."
Academician Pan took the document and glanced at it a few times, his eyes slightly condensed:
"This is topological susceptibility? It is actually 0?"
Xu Yun nodded heavily:
"That's right."
Upon seeing this, Academician Pan paused for a moment and then handed the document to several other big guys, who all took turns to read it.
in theoretical physics.
Witten and Veneziano once named a relationship called the Witten-Veneziano relationship.
Its content is not important. The key is that the left side of the formula is the topological magnetic susceptibility of vacuum, which describes the fluctuation of topological charges.
As for topological charges
This thing, like the Fermi surface, can also be divided into two concepts.
One type of topological charge is the topological charge related to the photonic crystal flat plate radiation, and the other is the topological charge concept in the orbital angular momentum OAM.
The situation mentioned here is naturally the latter, and the topological charge in the orbital angular momentum OAM will not be 0 only under pure gauge theory.
all in all.
The current topological susceptibility of the report in Xu Yun's hand is 0, which means that its property framework is a non-pure gauge theory.
Then here comes the problem.
How can we make the property framework of a particle a non-pure gauge theory?
That's right.
The smart classmates must have thought of it again.
That is.
It has at least one gauge group that is non-Abelian.
The Lagrangian operator of all non-Abelian gauge theories must contain a Yang-Mills term:
LA=14Fμνa(x)Faμν(x).
Think of this.
Higgs on the side thought of something again.
With the help of his assistant, he returned to the large terminal where Witten had input data earlier, and retrieved certain contents.
Academician Pan looked thoughtfully at the well-behaved Xu Yun beside him.jpg.
This guy's performance today was a bit impressive.
After a while.
This particle physics expert turned his head suddenly, the movement was so big that the balls on both sides of his cheeks were trembling:
"Hey Pan, the decay factor doesn't match the gauge potential, it's too big!"
Upon hearing this, Academician Pan looked at each other and a few others, and a slightly excited expression gradually appeared on his face.
Sure enough there is a problem!
If we say that the previous eigenvalues, scalar field expressions and the topological susceptibility discovered by Xu Yun are just some minor anomalies.
Then the difference between the decay factor and the gauge potential connected in series based on the Yang-Mills term LA≡14Fμνa(x)Faμν(x) is a big problem that cannot be ignored.
Take the human body as an example.
In life, everyone generally encounters various minor symptoms.
For example, occasional coughing, tinnitus, certain tendons in the hands and feet beating very fast, etc.
These problems can be big or small, and you can ignore them if you don't want to go to the hospital.
But if you have symptoms such as black blood in your stool or coughing up blood, then the situation cannot be ignored and you must go to the hospital for examination.
The decay factor currently derived based on the topological magnetic susceptibility discovered by Xu Yun falls into the latter category.
That is to say, there is indeed an abnormality in this particle that is obviously unreasonable.
More importantly.
The cause of "fever" may be one of many conditions such as cold, fever, pneumonia or even enteritis.
Although the symptoms of "blood in the stool" are much more serious, it is relatively easy to find the bleeding point and determine the problem.
For example, the difference between the decay factor and the gauge potential.
The only possibility that leads to this situation is that there is a problem with the CP broken link, which can be described in mathematical language
A non-zero vacuum expectation occurs in a certain field.
Of course.
The order here is that the mathematical language is derived from the physical observation data, that is, there is no need to use physical experiments to prove the guess.
"Non-zero vacuum expectation value."
After everyone sat back down.
Polyakov looked at Mr. Yang beside him and asked:
"Yang, tell me what you think."
"You are the person who named Yang-Mills Field. When it comes to the field of CP breakthrough, no one among us can compare with you."
The rest of the people also nodded after hearing this.
CP is broken.
This is also a very important concept in particle physics, and it can even be ranked among the top in terms of importance.
It does not mean to dismantle CP, but a combination phenomenon.
Where P refers to parity and C is charge.
Very long ago.
A female mathematician Noether proposed a Noether theorem, which simply means that a symmetry corresponds to a conservation.
She described conservation situations in the world into three types:
Time translation symmetry corresponds to energy conservation.
The translational symmetry of space corresponds to the conservation of momentum.
The rotational symmetry of space corresponds to the conservation of angular momentum.
These three relationships of symmetry and conservation are now recognized and are the source of all evil.
After Nott.
Another physicist, Wigner, discovered that there is another kind of symmetry, namely mirror symmetry.
For example, your left and right hands, or you and yourself in the mirror.
He believed that there should also be a conservation of this symmetry. Wigner called this conservation of parity, that is, parity.
Later, the physics community proved the accuracy of parity conservation in physical experiments under electromagnetic interaction and strong interaction, so it was believed that parity P was indeed conserved.
But around 1950.
Mr. Yang and Mr. Li discovered a problem:
There was no experimental support for the conservation of parity in weak interactions, so they proposed the idea of non-conservation of parity.
Later, the Chinese physicist Ms. Wu Jianxiong discovered parity nonconservation in the decay reaction of cobalt. Yang and Li quickly won the Nobel Prize in Physics, becoming the Nobel Prize winners with the shortest time from publication to award. .
If the above sentence is difficult to understand, here is a simple example.
You must have looked in the mirror before.
You touch your face, and you in the mirror touch your face too;
You make a face, and you in the mirror make a face too.
This is parity conservation, but this is a phenomenon that only occurs at the macroscopic level.
In the microcosm you will find a problem:
Sometimes when you touch your face, you in the mirror are waving your hands.
This is called parity nonconservation.
Yang Lao's parity non-conservation predicted that in the microscopic world, your movements may be inconsistent inside and outside the mirror. This anomaly was finally confirmed by scientific experiments.
So strictly speaking.
The first person in history to discover that parity is not conserved should be Jia Rui from Dream of Red Mansions. Unfortunately, the Nobel Prize was not yet born when Cao Xueqin died, ahem
As for charge non-conservation, the same is almost the same, but its official name is charge parity non-conservation:
At first, the physics community believed that charge parity was conserved. However, in 1964, Cronin and Fitch discovered that K mesons did not follow the existing mirror symmetry and charge symmetry during the radioactive decay of K mesons.
Therefore, this C+P is double symmetry breaking, also called CP breaking or CP breaking, depending on what you call it.
By the way.
The person who answered the symmetry violation was Makoto Kobayashi who had previously conducted experiments at Neon. He and his senior brother Toshihide Masukawa solved this problem. This is the famous Kobayashi-Masukawa theory.
His eyes returned to reality.
After listening to Polyakov's question, Mr. Yang picked up the report and looked at it a few more times and said:
"Everyone should know that although CP violation is a common phrase, there are currently not many particles that meet double symmetry breaking at the same time."
"Many times what is broken is the conservation of parity, not the parity of charge, even to a certain extent"
"The number of particles capable of charge parity violation can be counted."
Witten understood what Mr. Yang meant:
"Yang, so what kind of particle do you think may be causing charge parity violation?"
Mr. Yang glanced at him and thought:
"Pi mesons are definitely impossible, because pi mesons were 'donated' to Pangu particles by Λ4685 hyperons. Well, let's use lone point particles in this sentence."
"In addition, K meson is impossible because it has a singular eigenstate, and we have not observed this eigenstate bulge."
"As for the neutrino, it is obviously even less likely - it was still a dark matter candidate before today."
Hear this.
David Gross on the side interrupted:
"So Yang, do you think it may be an anomaly caused by W or Z bosons?"
Mr. Yang hummed softly and turned to look at Fermilab representative Bruce Arnold who had not come over:
"It is possible. Do you still remember the research on the overweight W boson by Fermilab in 2022?"
Witten was stunned for a moment, then blurted out:
"You mean DOI:10.1126/science.abk1781?"
Mr. Yang nodded.
The research that Mr. Yang mentioned was published in April 2022. At that time, "Science" gave it an unprecedented front page push.
The content of the article is very simple:
Fermilab experts have continuously analyzed the W boson data produced by the Tevatron collider in the 10 years from 2002 to 2011, and found that the mass of the W boson is 80433±9.4 MeV, which is higher than the standard model. The predicted value is 76 MeV heavier - equivalent to a difference in mass of 152 electrons.
And the deviation between this measurement result and the theoretical value reaches.
7 σ.
Mentioned earlier.
In particle physics, 5 σ can be regarded as a truly new physical discovery.
More importantly.
In the standard model, the mass of the W boson is given by the Higgs mechanism:
The Higgs mechanism causes the electroweak symmetry of SU(2)×U(1) to spontaneously break, producing Goldstone bosons.
The W boson then absorbed Goldstone as its longitudinal mode, thus gaining mass.
The mass of the W boson is greater than the prediction of the standard model, which may indicate that there is a problem with the Higgs mechanism.
Either
In a certain area, there is a brand new fundamental particle.
The global physics community is currently waiting for the verification of the LHC. After all, this is currently the most authoritative piece of equipment in the world.
The LHC, on the other hand, is like an author who started out of chapters, clamoring to start every day, but it never turns on.
all in all.
Many people are always beeping that there are no great discoveries in the physics world, but in fact, basic physics has quietly faced a huge crisis, and the physics building is likely to collapse again. (You can keep an eye out here. It is said that the LHC will start verification in July this year. If it is true, it will be great fun)
Then Witten looked at Mr. Yang again, his expression thoughtful.
Mr. Yang’s meaning is actually very obvious:
The abnormality of the particle may be due to the influence of the W boson.
That is to say, the Higgs field appears in a quantum mechanical vacuum in an unsteady state, and the continuity of the entire physical system is spontaneously broken, triggering the entire anomaly from the Weinberg angle.
How do you say this?
It seemed reasonable, but Witten felt a little uncomfortable.
After all, the research has reached this stage. Looking at all the participants at the scene, except for a few exceptions such as Suzuki Atsushi, everyone must be thinking about discovering more interesting things.
So Mr. Yang's statement seemed to answer the question, but the expected value was a bit different from what Witten thought - because the impact of this particle on the W boson had been observed before the meeting.
To put it bluntly
This explanation seems somewhat unworthy of its final ‘identity’ in this press conference, and also unworthy of the risks that Witten has taken for it.
After all, CP deficiency is not his professional direction, and Witten has not much interaction with it.
Think of this.
Witten couldn't help but sigh in his heart.
Whatever.
If there is a gap, there will be a gap.
At least this particle does exist, and it can be regarded as an advertisement for his ability in mathematics, but it is not without gain.
It can only be said that the intersection between this particle and him is not that deep, and he will definitely have little chance to participate in subsequent research.
And just when Witten was in a trance.
Out of the corner of his eye, he suddenly caught sight of Xu Yun approaching Mr. Yang and whispering something.
Then under the watchful eye of Witten.
Mr. Yang's somewhat tired eyes lit up inexplicably, and the expression on his face became much more vivid, as if
He heard something that surprised him.
Then Mr. Yang picked up the previous report again, pressed the tip of his thumbnail against a certain line, and scratched slowly from left to right.
Half a minute passed.
Mr. Yang couldn't help but let out a sigh, attracting everyone's attention.
See this situation.
Academician Pan glanced at Xu Yun and couldn't help but asked Mr. Yang:
"Old Yang, what are you doing?"
Unexpectedly, Mr. Yang ignored him, but waved his hand and continued to check the report.
When Xu Yun saw this, he didn't want to disturb Mr. Yang. He could only shrug at his teacher and express that he was helpless.
that's all.
After three or four minutes, Mr. Yang slowly raised his head and looked directly at Witten:
"Mr. Witten, we seem to have made a mistake."
Witten was startled:
"Error?"
"Yes, if the entire value is an anomaly caused from the Weinberg angle, then the coupling constant of the abnormal magnetic moment should also have an obvious abnormality within that frame, right?"
Witten thought for a while and affirmed:
"Yes, based on this deviation value, the energy scale change of the coupling constant should be more than 10, but not more than 15."
"Then you can calculate its abnormal movement magnitude now."
Xu Yun on the side heard this and immediately handed the pen and paper to Witten obediently.
Witten subconsciously took the paper and pen, glanced at Mr. Yang, then at Xu Yun, lowered his head and began to calculate.
Weinberg Point.
This is also a very important parameter in the unified theory of weak electricity. It is not difficult to tell who the contributor is from the name.
It can be defined by the inverse cosine function of the mass ratio of the W boson to the Z boson, which is approximately 29 degrees - of course, it is an abstract angle.
The value of this angle cannot be derived from first principles theory and can only be measured experimentally.
So to some extent.
The electroweak unification is only at a certain energy level, and the boundaries between the two basic forces are blurred.
The inner mechanism of the physical laws that cause this kind of running with the energy scale is currently not understood by the scientific community - at least from the level of accepted theory.
Therefore, Witten can only infer the Weinberg angle from the wrong data first, and determine the covariant derivative through weak supercharge, which is represented by the two-component back-base component.
Of course.
A calculation of this magnitude is naturally not a problem for Witten.
So it's quick.
Witten calculated the value of the coupling constant of the abnormal magnetic moment.
However, when writing the final result, Witten's pen suddenly paused and his face showed surprise.
He looked up at Mr. Yang for the second time, and then at Xu Yun.
Then he lowered his head again, scrawled a few times on the paper with his pen tip, and calculated again.
When Mr. Yang saw this, he didn't say much, but just watched Witten calculate.
This time.
Witten's calculations lasted
Fourteen minutes.
Fourteen minutes later.
Witten raised his head for the third time, but this time he looked around at the people around him before saying to Mr. Yang:
"1.53, the energy scale change of the coupling constant is only 1.53."
Gulu——
Witten swallowed hard. At this moment, he felt that his lips were a little dry:
"Yang, so... your previous guess was wrong?"
"Yes, something went wrong."
"So what's the real reason?"
Mr. Yang was silent for a moment and said slowly:
"Edward, before the experiment started, you once gave the example of Pluto and used Pluto's influence on Uranus to explain the existence of unknown particles."
"In that case, you should also know that there is something very special about the planet Pluto."
"That is, it has a satellite that is not very different in size from it, called Charon, also known as Charon. The two face each other like twins."
Witten nodded subconsciously, but he still didn't understand Yang Lao's purpose of mentioning Pluto again.
But after a few seconds.
He suddenly realized something, his eyes were as big as 30 Li Ronghao's, and he looked at Mr. Yang in shock:
"Yang, what do you mean"
Mr. Xu nodded slightly towards him, leaned back on his seat, and said in a somewhat emotional tone:
"Yes. We have regarded the number 923.8 GeV as the energy level of a particle from the beginning, but is there actually a possibility?"
"These are actually two particles that are very close to each other. They are always."
"Where are we holding hands?" (End of Chapter)