Four neutrons can be combined, is this a miracle or a mistake in physics

The nucleus is made up of protons and neutrons, which are tightly bound together through strong interactions. The structure of atomic nuclei is not simple, they come in different shapes, sizes, spins, excited states, etc. The nature of the nucleus depends on the arrangement of protons and neutrons, as well as the interactions between them.

Physicists use different models to describe the structure of atomic nuclei, such as droplet models, shell models, collective models, etc. Each of these models has its own advantages and limitations, and can explain some experimental phenomena, but some cannot be explained. Therefore, the structure of the nucleus remains an interesting and complex area of study.

In this article, I am going to introduce a very peculiar phenomenon about the nucleus of an atom, and that is the existence of four neutrons. Four neutrons refer to particles that are made up of four neutrons. You may ask, how can four neutrons be combined? Isn't that a violation of the basic principles of physics? That's a good question, let's see how physicists answer.

1. The theory of the four neutrons

The theory of the four-neutron dates back to the 30s of the 20th century, when physicists discovered neutrons and began to study the interaction between neutrons and atomic nuclei.

They discovered that neutrons can be absorbed by the nucleus, causing the nucleus to fission into two or more smaller nuclei. These processes release a lot of energy, which is where nuclear energy comes from. Physicists have also discovered that neutrons also interact with each other, but this interaction is weak and can only be manifested when the distance between neutrons is small.

Physicists soon began to wonder if there were particles made up of multiple neutrons, such as two, three, and four neutrons. They used mathematical and physical methods to calculate the likelihood of these particles, and found that the two and three neutrons are unstable and will quickly decay into one neutron and one proton, or two neutrons and one helium nucleus.

However, they found that the tetraneutron has a certain stability, it can exist for a period of time before decaying into other particles. This is because the structure of the four-neutron has a special symmetry that makes it a little less energetic than other combinations. This symmetry is called Wigner hypermorphism, and it is a quantum mechanical phenomenon that we will not explain in detail here.

Physicists are excited about the theory of the four-neutron, and they hope to observe the existence of the four-neutron experimentally. They came up with some possible ways to produce four neutrons, such as bombarding the nucleus with high-energy particles, or irradiating the nucleus with a neutron source, or using the process of nuclear fission to produce four neutrons.

They use a variety of instruments to detect the signals of the four neutrons, such as cloud chambers, scintillation counters, gas detectors, etc. However, none of them succeeded, and they did not find any signs of the four neutrons.

This disappointed them and made them wonder if the theory of the four neutrons was correct. They began to revise their theory to consider some other factors, such as how the tetraneutron decayed, how it decayed, how long it decayed, how it decayed, how it went, how it went, They also tried to describe the structure of the four neutrons with different models, such as the boson model, the fermion model, the molecular model, etc. However, none of these efforts have brought breakthrough results, and the four neutrons remain a mystery.

Experiments with two and four neutrons

The theory and experiments of the four-neutron continued into the 21st century, and physicists did not give up on the exploration of the four-neutron. They use more advanced technology and equipment to conduct experiments, such as accelerators, detectors, computers, etc. They also use more precise methods to analyze experimental data, such as Monte Carlo simulations, Bayesian statistics, machine learning, etc. They hope to find some new clues, or to confirm or deny the existence of the four neutrons.

Among these experiments, one that caught the attention of many people was the one conducted by Fujioka and others in Japan in 2023: they used a nuclear reactor to produce thermal neutrons, and then used those neutrons to bombard a uranium-235 target.

Their aim was to observe the fission process of uranium-235 to see if four neutrons were produced. They used a strontium-88 detector to detect the signals of the four neutrons, because strontium-88 can be transformed into strontium-91 through a four-neutron-induced reaction, and strontium-91 emits γ rays through β decay. They believe that if the γ rays of Strontium-91 can be observed in the detector, then there are four neutrons.

The results of the experiment were surprising, they observed γ rays of strontium-91 in the detector, and the intensity and energy of these γ rays were consistent with the theoretical predictions of the four neutrons. These results, they argued, showed that they observed particle-stable tetraneutrons.

The controversy over the three and four neutrons

Although the results of Fujiokan et al.'s experiments are exciting, they have also caused a lot of controversy. The results of their experiments differed greatly from those of previous ones, and there was some criticism of their experimental methods and analytical methods.

Some physicists believe that the results of their experiments may be due to other factors, such as background noise, detector efficiency, data processing errors, etc. They asked Fujioka and others to provide more details and evidence, or to repeat their experiments, in order to verify their conclusions.

Other physicists believe that Fujiokan et al.'s experimental results may be true, but their theoretical interpretation is wrong. They believe that the tetraneutron is not a particle-stable particle, but a short-lived resonance state, that is, a tetraneutron is an excited state that exists for a short time, which can be produced by some special reactions, but quickly decays into other particles.

They believe that the γ rays of strontium-91 observed by Fujioka et al. are not due to a four-neutron-induced reaction, but to other reactions, such as a three-neutron-induced response, or a two-neutron-induced response. They used different models and parameters to calculate the likelihood of these reactions and found that they matched the experimental data.

There are also physicists who believe that the experimental results and theoretical explanations of Fujiokan and others are correct, but their theories need to be further developed and refined.

They believe that the tetraneutron is a new nuclear physical phenomenon, which reveals some new characteristics and laws of nuclear force, and that the existence and stability of the tetraneutron may be related to some new physical mechanisms, such as quantum chromodynamics, supersymmetry, superstring theory, etc. They used these theories to try to explain the properties of the four neutrons, and could find many interesting predictions and outcomes.

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Source: Vientiane Experience

Editor: Zizhu and