Cesium vapor helps in the search for dark matter
The hunt for dark matter is one of the most exciting challenges facing fundamental physics in the 21st century.
Researchers have long known that it must exist, as many astrophysical observations would otherwise be impossible to explain. For example, stars rotate much faster in galaxies than they would if only ‘normal’ matter existed.
In total, the matter we can see only accounts for, at the most, 20 percent of the total matter in the universe meaning that a remarkable 80 percent is dark matter.
But so far no one knows what dark matter is made of. Scientists in the field are considering and researching a whole range of possible particles that might theoretically qualify as candidates. Among these are extremely lightweight bosonic particles, currently considered to be one of the most promising prospects.
These can also be regarded as a classical field oscillating at a specific frequency. But we can’t yet put a figure on this and therefore the mass of the particles, explained Budker. Our basic assumption is that this dark matter field is coupled to visible matter and has an extremely subtle influence on certain atomic properties that would normally be constant.
It employs atomic spectroscopy and involves the use of cesium atom vapor. Only on exposure to laser light of a very specific wavelength do these atoms become excited. The conjecture is that minute changes in the corresponding observed wavelength would indicate coupling of the cesium vapor to a dark matter particle field.
With their new technique, the scientists have now accessed a hitherto unexplored frequency range in which, as postulated in relaxion theory, the effects of certain forms of dark matter on the atomic properties of cesium should be relatively easy to spot. The results also allow the researchers to formulate new restrictions as to what the nature of dark matter is likely to be.
The study is published in johaness gutenberg universitaet mainz