# The most accurate value of the fine structure constant is calculated

Under the guidance of a professor at the Sorbonne University Saida Gelatti-Khelifa, physicists from France have clarified the value of the fine structure constant, a constant that determines the appearance and properties of our universe.

Among one of the main tasks of physics in the study of the universe is the understanding: have the laws of physics always been the same, in particular before and after the Big Bang? Specifically, they are interested in knowing whether the value of the fine-structure constant has changed. This constant determines the nature of the interactions between electromagnetic radiation and matter.

According to the last calculations, it is equal to a fraction, where there is one in the denominator and 137.035 in the numerator. However, as observations of white dwarfs and distant quasars show, it could have been different during the youth of the universe.

To calculate the constant value more accurately, a group of scientists from France observed the speed with which a rubidium atom begins to move, illuminated by a laser with a precisely adjusted power, size, and shape. The researchers decided to express the constant using indirect values: they cooled the atoms of rubidium or cesium to a temperature close to absolute zero. They then observed how they interact with particles of light.

After that, using a laser, they measured the speed at which the atom was moving, with the help of which they measured its mass. Further, this value is used to calculate the electron’s mass: it allows you to determine how tightly it is bound to the atom. It is through this ratio that the fine structure constant can be calculated.

Thanks to this, the scientists tripled the calculations’ accuracy and obtained the value of the fine structure constant with a record low error of 80 parts per trillion. According to their calculations, this value is one divided by 137.035999206 (11).

This value completely coincides with the theory of all elementary particles’ interaction but strongly disagrees with the previous estimates of the constant. Physicists hope that further experiments will help to find out what is the reason for this and will allow scientists to test for the first time whether electrons have the same anomalous magnetic properties as muons, their heavy counterparts.