The Large High Altitude Air Shower Observatory (LHAASO) is a gamma-ray and cosmic-ray observatory in China that is designed to observe air showers activated by gamma rays and cosmic rays.
Big High Altitude Air-shower Observatory (LHAASO) illustration. Credit: LHAASO
Scientists from the Institute of High Energy Physics of the Chinese Academy of Sciences took a look at the validity of the theory of relativity with the greatest accuracy in a research study entitled “Exploring Lorentz Invariance Violation from Ultrahigh-Energy? Rays Observed by LHAASO,” which was released in the latest concern of Physical Review Letters.
According to Einsteins theory of relativity, the fastest speed of matter in the Universe is the speed of light. Whether that limit is breachable can be checked by analyzing Lorentz symmetry breaking or Lorentz invariance infraction.
” Using the worlds highest energy gamma rays observed by the Large High Altitude Air-shower Observatory (LHAASO), a large-scale cosmic ray experiment in Daocheng, Sichuan province, China, we checked Lorentz balance. The result improves the breaking energy scale of Lorentz proportion by dozens of times compared to the previous best result. This is the most rigorous test of a Lorentz proportion breaking kind, validating when again the validity of Einsteins relativistic space-time balance,” said Prof. BI Xiaojun, one of the papers corresponding authors. Prof. BI is a scientist at the Institute of High Energy Physics and a member of the LHAASO cooperation.
What is the relationship in between Lorentz symmetry and the theory of relativity?
Einsteins theory of relativity, the cornerstone of contemporary physics, requires that physical laws have Lorentz proportion. In the more than 100 years given that Einstein proposed his theory of relativity, the credibility of Lorentz symmetry has actually undergone numerous speculative tests.
There is an irreconcilable contradiction between basic relativity, which describes gravity, and quantum mechanics, which explains the laws of the microscopic world. In order to unify basic relativity and quantum mechanics, theoretical physicists have made constant efforts and have established theories such as string theory and loop quantum gravity theory. These theories anticipate that Lorentz balance is most likely to be broken at really high energies, which means relativity might need to be customized at high energies.
It is essential to evaluate the theory of relativity and establish more essential laws of physics by looking for signals of Lorentz balance breaking. However, according to these theories, the impact of Lorentz proportion breaking is just substantial at the so-called Planck energy scale, which depends on 1019 GeV (1 GeV = 1 billion electron volts).
Given that artificial accelerators can just reach about 104 GeV, the impacts of Lorentz proportion breaking are too weak to be tested in labs. There are very violent astrophysical processes in the universe where particles can be accelerated to energies much greater than what man-made accelerators can reach. Astrophysical observations are a natural laboratory for looking for the effects of Lorentz balance breaking.
LHAASO is a large-scale cosmic ray experiment in China. Throughout the process of construction in 2021, the worlds highest energy gamma ray event was taped by LHAASO, with its energy approximately 1.4 PeV (1 PeV = 1015 electron volts). At the exact same time as setting a world record, it also supplied an important chance for checking out the fundamental laws of physics, such as Lorentz balance.
Lorentz balance breaking may trigger high-energy photons to become unsteady, rapidly decaying into an electron-positron set or into 3 photons. “In other words, the high-energy photons immediately vanish on their journey to Earth if Lorentz symmetry is broken, which indicates the energy spectrum we determined must be truncated at a specific energy,” said Prof. BI.
The information from LHAASO program that the current gamma ray spectrum continues to high energies above PeV, and no “strange” disappearance of any high-energy gamma ray occasions has been found. When approaching the Planck energy scale, this result reveals that Lorentz proportion is still kept.
Recommendation: “Exploring Lorentz Invariance Violation from Ultrahigh-Energy? Rays Observed by LHAASO” by Zhen Cao et al. (LHAASO Collaboration), 3 February 2022, Physical Review Letters.DOI: 10.1103/ PhysRevLett.128.051102.
” Using the worlds greatest energy gamma rays observed by the Large High Altitude Air-shower Observatory (LHAASO), a large-scale cosmic ray experiment in Daocheng, Sichuan province, China, we evaluated Lorentz symmetry. The outcome enhances the breaking energy scale of Lorentz proportion by lots of times compared with the previous finest result. These theories forecast that Lorentz proportion is likely to be broken at extremely high energies, which means relativity may require to be customized at high energies.
Considering that synthetic accelerators can only reach about 104 GeV, the effects of Lorentz balance breaking are too weak to be tested in labs. Astrophysical observations are a natural lab for looking for the effects of Lorentz proportion breaking.
