A new Chalmers study, together with ETH Zurich, Switzerland, offers a promising way to detect elusive dark matter particles through previously unexplored atomic reactions occurring in the detector material.
The new calculations allow theorists to make detailed predictions about the nature and strength of interactions between dark matter and electrons that were not previously possible.
“Our new study of these atomic reactions reveals material properties that have so far remained hidden. They cannot be studied with any of the particles available to us today ̵
For every star, galaxy or dust cloud visible in space, there is five times more material that is invisible – dark matter. Finding ways to detect these unknown particles that form such a significant part of Milky Way it is therefore a top priority in astroparticle physics. In the global search for dark matter, large detectors have been built deep underground to try to capture particles as they bounce off atomic nuclei.
So far, these mysterious particles have escaped discovery. According to Chalmers researchers, a possible explanation may be that the particles of dark matter are lighter than protons and thus do not cause the nuclei to recede – imagine that a ping pong ball collides with a bowling ball. Therefore, a promising way to overcome this problem could be to shift the focus from the nuclei to the electrons, which are much lighter.
In a recent article, researchers described how dark matter particles can interact with electrons in atoms. They suggest that the rate at which dark matter can eject electrons from atoms depends on four independent atomic reactions – three of which have previously been unidentified. They calculated the ways in which the electrons in the argon and xenon atoms used in today’s largest detectors must react to dark matter.
The results were recently published in the journal Physical Review Research and were carried out as part of a new collaboration with condensed matter physics Nikola Spaldin and her group at ETH. Their predictions can now be tested in dark matter observatories around the world.
“We tried to remove as many barriers to access as possible. The report is published in a fully open journal and the scientific code for calculating the new functions of the atomic response is open source, for anyone who wants to look “under the hood” of our paper, “said Timon Emken, a postdoctoral fellow in the dark group. matter to the Department of Physics at Chalmers.
Reference: “Atomic responses to general dark matter-electron interactions” by Ricardo Catena, Timon Emken, Nicola A. Spaldin and Walter Tarantino, August 5, 2020, Physical examination.
DOI: h10.1103 / PhysRevResearch.2.033195
More on dark matter
What is the universe made of? This question has fascinated humanity for millennia. Yet it remains largely unanswered, as more than three-quarters of the matter in our universe is thought to be made of particles so elusive that we do not know what they are. These particles are called dark matter and do not emit or absorb radiation at visible wavelengths. The discovery of unknown particles is a top priority for scientists around the world. To detect dark matter, researchers are looking for rare interactions between dark matter and electrons in deep underground detectors with low backgrounds.
There is indisputable evidence for the existence of dark matter in our universe. The evidence is based on the observation of unexpected gravitational effects in extremely diverse physical systems, including galaxies, galactic clusters, the cosmic microwave background, and the large-scale structure of the universe. While the European space satellite Planck has unequivocally shown that dark matter represents about 85% of all matter in the universe, its nature remains a mystery.
More about the scientific article
Read the article Atomic reactions of common interactions of dark matter and electrons in Physical examination. It was written by Ricardo Catena and Timon Emken from the Department of Physics at Chalmers and Nicola Spaldin, and Walter Tarantino from the Department of Materials at ETH Zurich, Switzerland.