Chapter 467: One in 42.9 billion chance
Note:
Before reading this chapter, I suggest you read Chapter 216, the part about the destruction of the world.
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First row.
Listen to these words coming from Witten's mouth.
The scene suddenly fell into a somewhat subtle silence.
Anton Salinger flipped through his pile of reports a few times, pulled out the one with the same number as Witten's, and put it in front of him to examine it carefully.
The other people quickly made the same move.
Another moment passed.
Anton Salinger put down the document, made eye contact with Academician Pan, and then said to Witten:
"Mr. Witten, your idea is indeed very innovative, but."
"With all due respect, there seems to be no charm quark in physics at present. No, it should be said that there is no evidence that quarks and gluons will transform"
Anton Salinger finished.
Many people, including many attendees, nodded at the same time.
Mentioned before.
The so-called hadron.
It refers to the particles participating in the strong interaction, including Meson and Baryon.
After the quark model is established.
The physics community came up with a method called deep inelastic scattering, which is the DIS method that many people are familiar with, to explore the structure of hadrons—hadrons at that time were mainly protons.
Simply put, it is to bombard protons with high-energy electrons, drive the electrons into the interior of the proton, and infer the internal structure of the proton through the analysis of the final particles.
Therefore, this experiment is also called the electron-proton deep inelastic scattering experiment.
DIS illustrates a very important concept:
Partons within a proton have the property of "asymptotic freedom".
Simply put.
The closer the parts are to each other, the weaker the strong force.
When part molecules are very close to each other, the strong force is so weak that they can act as free particles.
This phenomenon is called "asymptotic freedom".
On the contrary, the greater the distance between partons, the stronger the strong force.
In 1973.
Across the sea, scientists Gross, Politz, and Wilczek discovered that the non-Abelian gauge group under the SU(3) color gauge group has the property of asymptotic freedom, thus establishing a theory to describe the strong interaction—that is, Hehe The famous quantum chromodynamics, and won the Nobel Prize in 2004.
That's right.
Gross—that is David Gross, who is now sitting opposite Xu Yun.
There are two basic types of degrees of freedom, or two types of particles, in QCD:
One is quark, fermion, spin 1/2, which is the quark in the quark model.
The other is gluons, with spin 1, and bosons, which are media particles that transmit strong interactions.
That is, quarks form structures, and gluons glue them into hadrons.
To use a real-life example, quarks are almost like bricks, and gluons are like cement. Both are indispensable.
Among them, quarks have six colors: upper, lower, top, bottom, strange, and charming.
Gluons have eight states.
But the problem is
Although both are core substances of the strong nuclear force, there is currently no evidence to prove that there is any connection between the two in terms of conversion.
In other words, quarks are quarks, and gluons are gluons.
There is no way to complete the conversion by adding a meson, lepton, or whatever.
As the top or even number one physicist in the world, Witten cannot possibly not know this.
Facing Anton Salinger's question, Witten seemed very calm at the moment, as if he had been prepared for it.
He once again pulled out a document from the report and handed it to Anton Salinger:
"Mr. Salinger, please take a look at this."
Anton Salinger glanced at Witten first, then took the document and started reading it.
After a while.
Anton Salinger suddenly let out a sigh:
"Hey, is this a baryon number imbalance? Is the decay width of the coupled up-type quark field so narrow?"
Hear this.
Higgs, who was opposite Anton Salinger, moved the tips of his ears slightly and couldn't help but said:
"Mr. Salinger, what is the report number?"
Anton Salinger glanced at the footer:
"P292."
Higgs quickly read the corresponding report.
Baryon number.
This is a very core property of baryons. Under normal circumstances, the baryon number of baryons is conserved.
For example, in the beta decay of free neutrons, the baryon number before the reaction is +1, and the baryon number after the reaction is also +1.
The conservation of baryon number is caused by interaction and color confinement. Hadron collision experiments did not find that color confinement was destroyed, so there is only one theoretical possibility for baryon number imbalance:
A new canonical group has been added.
That’s right!
Students with good memories should remember it.
As mentioned in paragraph 35 of Chapter 463, the report discovered by Xu Yun showed that the property framework of particles is a non-pure gauge theory!
That is to say
The color space of quarks and the weak isospin space are directly summed.
Think of this.
Higgs suddenly realized something, took a breath, turned to Xu Yun and asked:
"Dr. Xu, can you please find out the matrix element canonical group calculation formula you calculated before?"
Xu Yun was a little surprised by Higgs's words, but he quickly nodded affirmatively:
"No problem."
After saying that, he came to his original position, quickly flipped through the pile of documents a few times, and pulled out a somewhat messy manuscript paper.
Then he walked to Higgs with the manuscript paper, scratched his head in embarrassment while handing it over, and said:
"Mr. Higgs, this is the canonical group expression. The process is a bit sloppy. Please bear with me."
Xu Yun's words are not "self-effacing". This calculation is indeed quite sloppy.
After all, the previous calculation time was very tight, and the content Xu Yun wrote must be mainly simplified. I never expected that Higgs would use this thing.
Fortunately, Xu Yun's handwriting is still three-dimensional. Although it looks a bit messy, it does not particularly affect the look and feel.
Then Higgs thanked him, took the manuscript paper and read it.
"The 24 generators include 8 gluons, 3 weak interaction bosons, and 1 photon. The standard model occupies 12 of them, and the remaining 12 are the newly introduced weak interactions."
"Three of the vector field bands, each with a charge of +4/3, couple the down-type quark field -1/3 and the charged lepton field with a charge-1 charge, realizing the mutual transformation of down-type quarks and charged leptons. ”
"The coupled up-type quarks carry a charge of +2/3 to achieve mutual annihilation of up-type quarks."
"Correspondingly, there are three anti-vector fields that couple the anti-particles of the above process to realize their anti-particle reactions."
Higgs was doing calculations while reading, and from time to time he would take Witten's document to check the parameters.
Ten minutes later.
Higgs looked at the results he calculated and looked up at Witten with a complicated expression:
"."
Everything is left unsaid.
As everyone knows.
Different from the U(1) gauge field of photons, gluons originate from the color gauge group of SU(3).
This results in gluons having self-interactions - like three-gluon vertices and so on.
At the same time, when the quark flavor number is less than 33/2, the β functions in QCD are all greater than 0, resulting in the phenomenon of asymptotic freedom.
in this case.
Once the color space of quarks and the weak isospin space are directly summed, a phenomenon may occur:
Charm quark pairs have a probability of annihilating into gluons (referenced from Weinberg's "Dream of the Ultimate Theory" and Grand Unified Theory. Of course, it is almost impossible to happen in reality. I ignored the axial vector flow anomaly)
In other words.
Whether it is a mathematical matrix or a test result - that is, a physical phenomenon, it all fits Witten's ideas at this time.
Or to be more precise.
This is the only idea that fits both sides.
Of course.
This has nothing to do with the discovery of structures smaller than quarks. It is a new quark decay state that is highly suspected to be real.
Pure quark decay is not uncommon.
For example, the most typical example is that after the up quark releases a positron and neutrino, it decays into a down quark.
It's just that what Witten and the others have discovered now is not the conversion between quarks, but the transformation process between quarks and other basic particles.
From a purely model perspective, quarks are still the smallest particles in existence.
Then soon, Nima on the side raised his hand again:
"Mr. Witten, there is no problem with this idea mathematically, and the phenomenon also supports its establishment, but"
"The probability of successful annihilation seems too low, even lower than one in 13.7 billion of the generation of double charm quark particles. It is simply unimaginable."
When Xu Yun on the side heard this, a strange emotion appeared in his heart, and he couldn't help but ask:
"Mr. Nima, what is the probability that charm quarks annihilate into gluons?"
Nima glanced at him and turned his manuscript paper towards him:
"One in 85.8 billion, a dicharm quark particle can be divided into two quark pairs, which means that 42.9 billion dicharm quarks must pay their 'life' before one can be converted into a gluon."
"If Double Charm Quark had life, perhaps she would definitely refuse this approach of committing suicide."
"After all, if the conversion fails, her ending will be the annihilation of quarks into photons, and she will disappear forever."
"That's not necessarily the case."
Xu Yun subconsciously retorted. After coming back to his senses, although he felt that it might be a bit rude to say this, he still said:
"Perhaps the dicharm quark particles were already prepared before their annihilation, determined to pay all costs and become gluons no matter what."
Nima's brows suddenly raised when he heard this. Now in his forties, he is still less stable than other big guys:
"Oh? This statement is quite interesting. So Dr. Xu, why do you think bicharmed quark particles must turn into gluons?"
Xu Yun thought for a while and guessed:
"Maybe. Maybe the particle she likes is a gluon?"
"After all, the degrees of freedom of the strong interaction are quarks and gluons. If particles are alive, it is not impossible for quarks and gluons to fall in love."
Looking at Xu Yun with a serious look on his face, he opened his mouth but finally said nothing.
Although his reason told him that this kind of thing was almost impossible to be true.
But when he saw the probability he calculated, he stopped thinking about refuting it.
After all
This is a phenomenon that occurs only after 42.9 billion impacts.
Even if it has nothing to do with love, it still should not be ridiculed or denied by words.
Xu Yun's words made the atmosphere at the scene feel a little depressed, but soon, Witten spoke again:
"Okay, everyone, in short, we have now successfully deciphered the reason why these two particles maintain such an attitude."
"Whether these two particles are related to love or not, this is something worth celebrating, isn't it?"
Only then did everyone come back to their senses and applauded one after another.
As Witten said.
As this mechanism is proven, the ‘state’ of these two particles becomes clear:
The dicharm quark is split into two particles, and the two particles they form have the same properties. According to the principle of quantum chromodynamics, they should repel each other.
But the strengthened gluons form a more stable and powerful chain, tightly imprisoning the two particles together, as if holding each other's hands, neither one is separated.
No wonder Xu Yun would say this is love.
all in all.
After solving this problem.
The next link. Or the only link left is.
How about analyzing the specific structure of particles?
Is it a diquark particle?
Or three quarks?
Or four quarks or five quarks?
This kind of judgment is not difficult, after all, the necessary parameters are already there.
Although the current understanding of quarks in the physics world is still relatively limited, it is still relatively easy to determine the composition of a particle.
Now after determining the ‘state’ of the two particles.
As long as a gluon field and other parameters are introduced, the specific structure of the particle can be analyzed.
However, after a few minutes of calculation.
Witten's pupils suddenly shrank, and he stared at the manuscript paper in his hand:
"This is"
Note:
The PCT index is a bit high. The doctor doesn’t let me go home at night to code. I can only update 4,000 in the past two days to maintain attendance, which is hard to bear. Also, don’t mention the suggestion of asking for leave. I remember explaining the reason before
The press conference ends within two chapters. (End of chapter)