The Science Fiction World of Xueba

Shen Jing thought for a while and said, "Okay, then let's make an agreement. If you still can't think of a way to save me after one year, then you must agree to my request."

Pang Xuelin smiled and said, "No problem."

In the following time, the two let go of their respective thoughts and began to enjoy this holiday trip with ease.

Because of the flying car, the complex landforms of the Qinghai-Tibet Plateau are no longer an obstacle.

The majestic Himalayas, the winding Yarlung Zangbo Grand Canyon, and the large and small lakes scattered like sapphires on the Qinghai-Tibet Plateau allow Pang Xuelin and Shen Jing to fully appreciate the beauty of the roof of the world.

What surprised Pang Xuelei was that Shen Jing was not as sentimental as shown in the movie. He was quite open to the fact that he would be permanently trapped in the center of the earth, and the surface world would lose one glance. Care too much.

While Pang Xuelin was surprised, he also secretly lamented that the crew members who could be selected for the Sunset series of land spaceships are all very human.

At the same time, Pang Xuelin also vaguely realized that the reason why Zhong Shenjing behaved like that was more likely because when the hero took Shen Jing to the grassland, Shen Jing was trapped in the center of the earth not long ago, and his mentality had not fully adapted to life in the center of the earth.

But now, she is ready to live in the center of the earth for the rest of her life, and when looking at the outside world, her mood will naturally be different.

After finishing the three-day journey, Pang Xuelin returned to the base with Shen Jing's "eyes", told Shen Yuan about his gambling game with Shen Jing, and asked Shen Yuan to interrupt the communication between the base and Sunset No. 6.

Although Shen Yuan was curious about how Pang Xuelin found a way to save Sunset No. 6 within a year, since Pang Xuelin didn't say anything, Shen Yuan couldn't ask more questions for a while.

Afterwards, Pang Xuelin bid farewell to Shen Yuan and returned to Beijing. As the deputy chief engineer of the Earth Cannon Project, he went to the Institute of High Energy Physics of the Chinese Academy of Sciences to start research on neutrinos.

In this world, although the overall level of science and technology is a bit higher than the real world, in the fields of basic physics and basic mathematics, there is not much difference between the two.

Similar to the real world, in this world, after the discovery of the Higgs boson, particle physics entered a new stage.

The discovery of the Higgs boson, the last building block of the Standard Model of particle physics, spells the end of an era and the beginning of a new one.

The Standard Model is a theoretical system that systematically describes the entire particle physics and has been tested by a large number of experiments.

After the discovery of the Higgs particle, the Standard Model is approaching perfection, with a beautiful structure and amazing predictive power.

But on the other hand, there are some phenomena that cannot be accommodated by the standard model, such as dark matter, dark energy, the asymmetry of positive and negative matter in the universe, neutrino mass, etc., or are difficult to explain, indicating that there must be new physics beyond the standard model.

In the Standard Model, neutrinos are massless.

The discovery of neutrino oscillations shows that neutrinos have mass.

This is the only phenomenon discovered so far that has solid experimental evidence beyond the Standard Model.

There are three types of neutrinos: electron neutrinos, m neutrinos, and t neutrinos.

They have zero mass in the Standard Model.

In 1956, Li Zhengdao and Yang Zhenning predicted the non-conservation of weak-action parity, that is, the left-right asymmetry of space, which was soon confirmed by Wu Jianxiong with experiments.

Experiments also found that parity is not only not conserved in the weak interaction, but also the most destructive.

The reason for this phenomenon is that there are only neutrinos with left-handed helicity (that is, its spin is always opposite to the direction of motion), and there are no right-handed neutrinos.

This can only be established if the mass of the neutrino is zero, because if the mass is not zero, then the speed of the neutrino must be less than the speed of light, you can choose a reference system faster than it, and let its helicity

Live flip.

According to this phenomenon, Li Zhengdao and Yang Zhenning put forward the two-component theory of neutrinos, which gave birth to the weakly acting V-A theory, which was inherited by the standard model and was in good agreement with various experimental data.

Therefore, in the Standard Model, neutrinos are massless.

However, in 1998, the Super-Kamiokande Experiment (Super-K) in Japan discovered that there is an oscillation phenomenon in atmospheric neutrinos, that is, neutrinos can change into other types of neutrinos during flight.

Together with the earlier mystery of the disappearance of solar neutrinos and the results of experiments such as SNO (solar neutrinos), (reactor neutrinos) and K2K (accelerator neutrinos) later, the neutrino oscillation solid evidence.

Neutrino oscillations indicate that neutrinos have mass, but they are so small that even with the level of human technology in this world, it is still impossible to accurately measure the mass of neutrinos.

Incorporating the neutrino's mass into the Standard Model doesn't seem like a big deal, adding a mass term for it like the electron seems to do.

But two problems immediately arise.

One question is how to add. Neutrinos have a spin of 1/2 and are fermions.

All other fermions are charged, but neutrinos are not.

In this way, the neutrino can be a Dirac particle like other fermions, with a Dirac mass term, or it can be a special type of Majorana particle, that is, its antiparticle is itself, but with the opposite helicity .

Another problem is that the mass of the neutrino is too small. If you simply add a Dirac mass term, its mass is a trillion times different from the heaviest top quark.

The same Higgs particle needs to produce a mass as large as the top quark and a mass as small as a neutrino. Such a huge gap is hard to believe.

There is a kind of theory that is very popular among physicists, called the "seesaw mechanism", which assumes that neutrinos are Majorana particles, and there are undiscovered heavy neutrinos with a mass much larger than the electroweak energy scale. The tiny mass of the micron can be explained naturally.

However, heavy neutrinos cannot fit into the three-generation structure of the Standard Model.

Neutrinos hold a great deal of unsolved mysteries, both for physics in this world and for physics here on Earth.

Firstly, its mass has not been directly measured, and its size is unknown; secondly, it is not known whether the neutrino and its antiparticle are the same kind of particle; thirdly, there are two parameters of neutrino oscillation that have not been measured, and this Two parameters are likely to be related to the mystery of the absence of antimatter in the universe; fourth, whether it has a magnetic moment; and so on.

Therefore, neutrinos have become an interdisciplinary and hot subject of particle physics, astrophysics, cosmology, and geophysics.

Currently, in this world, neutrinos have two main applications.

One is neutrino communication.

Since the earth is a spherical surface, coupled with the shielding of buildings and terrain on the surface, the distance transmission of electromagnetic wavelengths must pass through communication satellites and ground stations.

However, neutrinos can pass through the earth, and their loss is very small when passing through the earth. The neutrinos produced by high-energy accelerators of 1 billion electron volts only attenuate by one-thousandth when passing through the earth. Therefore, neutrinos can be used from South America. The beamlet travels directly across the globe to China.

By modulating a beam of neutrinos so that they contain useful information, any two points on Earth can be communicated without the need for expensive and complex satellites or microwave stations.

The second application is neutrino earth tomography, or formation CT.

The interaction cross-section between neutrinos and matter increases with the increase of neutrino energy, and neutrino beams with an energy of more than one trillion electron volts generated by high-energy accelerators are used to irradiate formations in a directional manner, and the interaction with formation materials can produce local small "earthquakes" , similar to seismic exploration, it can also explore deep strata, and scan strata layer by layer.

However, the accuracy of this earth tomographic scan is quite limited, and the error has reached tens of kilometers. Under such conditions, trying to locate Sunset 6 in the earth's core through stratum CT is tantamount to finding a needle in a haystack.

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