Chinese physicists working in collaboration China Dark Matter Experiment (CDEX) began to search for hypothetical particles called dark photons and are candidates for dark matter. They managed to reveal the possible properties of the mysterious particles that will help to find them in the future. Article with the results of scientific work published in the journal Physical Review Letters.
To search for particle physicists have used experimental setup in the laboratory Jinping (CJPL), located underground at a depth of 2400 meters. It consists of three chains of germanium detectors with three elements, purified is surrounded by a copper shell with a thickness of 20 centimeters, which protects against background radiation. The whole structure is immersed in liquid nitrogen to maintain the low temperature.
If dark photons exist, then one way of detection is the interaction with the germanium detectors in the process similar to the photoelectric effect with normal light particles. The source of the dark photons may be the Sun, and particles with a low weight of about one hundred electron volts are the lower limit of the detection limit for the experimental setup.
The researchers analyzed data collected from February 2017 to August 2018. Although the signals indicating the existence of dark photons was detected, scientists have found new constraints on the properties of light dark matter particles, including the parameters of the mixing with photons of the Standard model, and how they can interact with ordinary matter.
In the future, scientists plan to improve the experimental setup that involves the use of a larger cryogenerator with liquid nitrogen with a volume of 1700 cubic meters and additional germanium detectors weighing up to a hundred pounds.
