Why is matter and antimatter asymmetry? answer or in gravitational waves

The current Big Bang theory holds that the universe we live in originated in a Big Bang 13.8 billion years ago, but it is also believed that the Big Bang produced an equivalent amount of matter and antimatter, and that positive and antimatter would disappear when they met, causing all to disappear.

Why is matter and antimatter asymmetry? answer or in gravitational waves

A phase change in the universe, which causes a small imbalance in the number of matter and antimatter, causes some matter to survive annihilation, a phase change that is likely to lead to the creation of cosmic strings, which produce gravitational waves, so detecting such gravitational waves may explain why we exist. Picture: Physicist Organization Network

But everything in the universe does exist, and what happens in the middle of this twisting and strange story? A new theory recently proposed by scientists in the United States, Japan and Canada suggests that phase changes in the early universe have turned neutrinos into more particles (more numerous than antiparticles), skewing the amount of positive and negative matter. This phase change also produces “cosmic strings”, which produce gravitational waves that detect them, or reveal the mystery of the asymmetry of positive and negative matter.

In response, Cai Yifu, a professor in the Department of Astronomy at the School of Physics at the University of Science and Technology of China, told Science and Technology Daily: “Even if the gravitational waves produced by cosmic strings are observed, it may take many conditions to further confirm this view.” However, this provides a new way of thinking to solve the mystery of the asymmetry of positive and negative matter. “

Neutrinos “Stand Up”

The Big Bang theory of modern cosmology holds that at the beginning of the Big Bang, the universe produced an equivalent amount of matter and antimatter. If the plot continues in this way, then material and antimatter will eventually “meet the narrow road” and annihilate each other.

But in fact, the universe we are now in is full of stars, full of all kinds of matter, which is contrary to the above theory. Therefore, in order for the universe to exist, a small amount of antimatter must be converted into matter, resulting in an imbalance in the number of positive and negative matter. Scientists believe that the amount of matter can be more than a billionth of antimatter to allow the universe to exist.

But when and how did this imbalance occur between positive and negative substances? It remains an unsolved mystery, one of the greatest in the universe. “It’s a difficult question to answer,” said Jeff Drew, a postdoctoral researcher at the University of California, Berkeley. “

Given that matter and antimatter charges are opposite, they do not convert to each other unless they are electrically neutral. Neutrinos are the only electrically neutral matter particles we know to date, and scientists have high hopes for it as a “no-brainer” to accomplish this sacred mission.

There are currently three neutrinos known: electron neutrinos, muse neutrinos, and ceramic neutrinos. But some scientists have suggested that there may be a fourth neutrino: an inert neutrino.

Some scientists believe that the universe has undergone a phase change after the swell, causing the inert neutrinos produced in the early universe to decay out more particles (more than antiparticles) and “reshuffle” the amount of matter and antimatter.

“When the temperature of the universe is 1012-1024 times the temperature of the hottest place in the universe today, the ‘behaviour’ of neutrinos may ensure the existence of the universe,” said Graham White, a co-author of the latest study and a postdoctoral fellow at the Canadian Laboratory of Particle Physics and Nuclear Physics (TRIUMF). “

Gravitational wave “curve salvation”

So how do you detect these inert neutrinos?

Researchers say scientists are now unable to observe inert neutrinos directly because experimenting to create inert neutrinos requires a particle accelerator that is much more powerful than the Large Hadron Collider, so it is only indirect to detect gravitational waves from cosmic strings or a “curve-saving” method.

“This phase change in the early universe may have created cosmic strings, which are essentially topological flaws in space-time,” said lead researcher Murayama, co-author of the study and a researcher at the Kavrie Institute of Cosmic Physics and Mathematics at the University of Tokyo in Japan. “

Cai Yifu explained to science and technology daily reporters: “Phase changes abound in our daily life, such as water frozen into ice, ferromagnets into paramagnets and so on.” The history our universe goes through is a history of constant phase-changing thermal expansion, in which elementary particles are produced, elements are synthesized into elements, and elements end up combining the familiar physical structures we see. “

“Phase change processes are accompanied by the release of energy, and cosmic strings are the same energy structures as the ropes that release energy as the universe goes through phase changes,” Cai added. “

Droe and Murayama, among others, believe that as these cosmic strings continue to evolve, gravitational waves will be produced, and the spectrum that produces gravitational waves is quite different from that of black holes and other astrophysical sources. Future gravitational wave observatories, such as the Square Kilometer Array (SKA), which will be launched by mid-2020, the European Space Agency’s Space Antenna Laser Interferometer (LISA), and the Japan Space Exploration Agency’s Hertz Interferometry Gravitational Wave Observatory (DECIGO), Perhaps these gravitational waves can be detected.

The researchers say there are other uses for finding gravitational waves from these cosmic strings, such as finding high-energy neutrinos produced by cosmic strings and more precise determination of the mass of known neutrinos.

In this regard, Cai Yifu said: “The cosmic string produces gravitational waves is not surprising, but we have not been lucky to find its ‘shadow’.” And even if we detect cosmic strings, the mechanism by which cosmic strings are produced is not unique, and the process behind the phase changes needs to be confirmed to confirm this view. “

In addition, Cai Yifu stressed: “The cosmic string, if charged, can use multi-messenger astronomical detection methods, such as rapid radio storm observation stoking these superconducting cosmic lines, so as to more three-dimensional, more clearly distinguish the ‘traces’ of cosmic changes.” “