In the dormitory building of SLAC, Chen Zhou is sitting at his desk, habitually pointing at the scratch paper with a pen.

Feynman once said, "If in a certain disaster, all scientific knowledge is destroyed, and only one sentence is passed on to the next generation, what sentence can use the smallest few words to contain the most information? I think it is the atomic hypothesis.

That is, all matter is composed of atoms.”

People now realize that atoms are composed of a nucleus and electrons outside the nucleus.

The nucleus is composed of nucleons, namely protons and neutrons.

So is there a more microscopic structure inside the nucleus?

The answer given by modern physics is that nucleons are composed of quarks.

For different quarks, physicists use "flavor" to distinguish them.

As for why "flavor" is used instead of other things.

There is a legend that Gell-Mann casually used the color and taste of ice cream to label physical quantities while eating ice cream while doing scientific research.

So currently, physicists have discovered 6 different "flavors" of quarks, namely up quark (u), down quark (d), charm quark (c), strange quark (s), top quark (t) and bottom quark.

Quark(b).

These different "flavors" of quarks also have corresponding antiquarks.

Speaking of which, the existence of up quarks was first proposed in 1964.

Then in 1967, deep inelastic scattering experiments conducted through the SLAC linear accelerator provided evidence for the existence of this quark for the first time.

As for the unique "flavor" of these quarks, the sum total is the flavor of hadrons.

The self-selected parity of a hadron is determined by the spin of the quarks and their mutual orbital angular momentum.

Mesons can be divided into two major categories according to their different "flavors".

One type is the neutral-flavored meson, which means that the positive and negative quarks are the same.

Just like up quark and down quark mesons, they are regarded as the same "flavor".

The other category refers to mesons with different “flavors” of charm quarks, strange quarks, top quarks and bottom quarks, that is, mesons with different “flavors” of front and back quarks.

For this kind of meson with "taste", it can be named according to its different "taste".

As for the naming of neutral-flavored mesons, it is not only based on the "flavor" of the meson, but also distinguishes whether the total spin of the quark pair is 0 or 1, and whether the orbital angular momentum is odd or even.

For example, baryons contain three quarks, which only need to be distinguished according to different "flavor" quantum numbers.

Hadrons in highly excited states are represented by the corresponding hadron name plus "*", and their mass is identified in brackets after it.

However, strong interactions allow new forms of matter to exist.

The glue ball composed of pure gluons that Chen Zhou was chasing with all his strength at this moment, but could not get a full glimpse of, was this new form of matter, also called the strange hadronic state.

In addition to glue balls, there are also hybrid states composed of quarks and gluons, and multi-quark states composed of three or more quarks, etc., which also belong to this strange hadron state.

Finding and studying these new forms of matter will provide important information for the formation of hadrons from quarks and gluons.

If strange hadronic states do not exist, it will mean that the basic theory of strong interaction needs major changes.

The strong interaction force exists between quarks.

This is the strongest interaction force currently known to humans in nature.

The strong interaction is transmitted through the gluon field, similar to the electromagnetic force transmitted between charges through the electromagnetic field.

A proton contains three quarks, and these three quarks form a bound state through the strong interaction transmitted by gluons.

Moreover, the mass of the three quarks that make up the proton only accounts for less than 2% of the mass of the proton. Most of the mass comes from the gluons participating in the strong interaction.

Therefore, studying glue balls composed of pure gluons is of extremely important significance.

Thinking of this, the pen in Chen Zhou's hand suddenly paused, and then he placed it on the draft paper.

Chen Zhou then opened his computer's browser and began searching for content related to strong interactions.

This is the last problem Chen Zhou has encountered in his current theoretical research on strange quantum number glue balls.

He needs to reasonably and fully explain a difficult problem in the strong interaction in order to finally reach that, which may be the commanding heights of the glue ball theory of strange quantum numbers.

While waiting for the browser page to jump, Chen Zhou glanced at the date and time in the lower right corner of the computer screen.

Today is March 7th, and seven days have passed since the last time Cross completed all the documentation.

There are still 24 days left before SLAC closes its collider laboratory.

Chen Zhou, who originally thought he had plenty of time, and had Cross's two days of preparation beyond his expectations, now felt that time was tight again.

It wasn't because of anything else, it was precisely because of the final problem he was encountering now.

Originally, Chen Zhou thought that he had solved the problem of the rubber ball experimental detection method in his previous research.

Unexpectedly, as the research on the strange quantum number glue ball became more and more in-depth, the originally innovative detection method of the glue ball experiment once again ran into the wrong set of questions when conducting paper-based experimental research.

When he saw this part of the content, Chen Zhou was stunned.

This was an unexpected surprise.

And this surprise cannot be said to be small.

If it cannot be solved, all their previous efforts will be in vain.

The final experimental plan that Friedman, Cross and others have been waiting for will be completed over time.

This is something Chen Zhou cannot allow.

No matter what the final experimental results are, before the experiment is carried out, the path of theoretical research must not stop with him.

Otherwise, he will be condemned in his heart.

Therefore, after discovering this problem, Chen Zhou did not stop for a moment, just thinking about how to quickly solve the problem.

But sometimes it happens that the more you want to solve something, the harder it becomes to solve it.

Its difficulty also rises exponentially.

"Strong interaction is contrary to our intuition. Unlike the strength of universal gravitation and electromagnetic force, which are inversely proportional to distance, for strong interaction, the closer the distance, the weaker it is, and the farther the distance, the stronger the force..."

Looking at the documents he found, Chen Zhou fell into deep thought again.

What this means, simply put, is that when you try to separate the quarks in a proton, the further apart they are, the stronger the force required.

Moreover, this force is strong enough to create a new pair of quarks in the vacuum without separating the original quarks.

Just like a magnet, when you break a magnet, you don't get two magnetic monopoles, but two new magnets.

This property of strong interaction is called "color confinement".

Chen Zhou was trapped by this "sexual confinement".

Chen Zhou shook his head slightly and shook away the complicated thoughts from his head.

He reached out and picked up the wrong question set aside and turned to the content of the glue ball experiment detection method.

While looking at it, I sorted it out on the scratch paper.

He tried to find something different in it, hoping to find a breakthrough from the content itself.

Speaking of which, the problem Chen Zhou is encountering now is about the theory of elementary particles.

Essentially, the theory of elementary particles is still a developing theory.

It is unsatisfactory in many respects.

In the theory of elementary particles, there are two theoretical issues of philosophical significance that need to be clarified.

One of them is the hierarchical structure issue.

The other is the problem of interaction unification.

"Color confinement" is a problem of interaction unity.

At the atomic level of the material structure, the electrons and nuclei in the atoms can be separated.

At the atomic nucleus level, the protons and neutrons that make up the atomic nucleus can also be separated from the atomic nucleus.

But after entering the "elementary particle" level, the situation changes.

This change is called "sexual confinement".

This is a question for which no clear answer has yet been found theoretically.

Although physicists have given many theoretical models for this, the models differ greatly, and it is difficult to verify and judge experimentally which model is correct.

Chen Zhou originally thought that he had avoided this problem that had troubled the physics community for decades and could go straight to Huanglong and unearth the long-hidden glue ball.

But I didn't expect that on the eve of the experiment, I would still be trapped here.

"Quarks are transferring and exchanging gluons, and at the same time, gluons are also emitting and absorbing gluons. This is equivalent to the process of gluons being transferred between quarks, and multiple gluons are 'strongly pulling' each other.

…”

Time passed slowly, and the draft paper on Chen Zhou's desk became more and more written.

However, the solution to the problem has never been found.
To be continued...