The experiment, whose goal was to search for the mysterious dark matter, gave scientists some unusual signals – and now the scientific community is confused.
From 2016 to 2018, researchers developed an experiment called XENON1T, the purpose of which was to uncover the secrets of dark matter. Since, according to scientists, this substance should be present almost everywhere, XENON1T should have looked for rare evidence of when its particles interact with “ordinary” matter.
For this, scientists installed equipment opposite a huge tank filled with several tons of liquid xenon. When any external particle penetrates through the reservoir, it excites xenon atoms and creates a flash of light, as well as a stream of free electrons, which XENON1T should detect.
It is noteworthy that such phenomena can be the result of not only contact with dark matter, but also with almost any known particles. In order to filter out the “garbage” matter, the team created theoretical models and made predictions of the expected disturbances, and then compared them with the real picture.
As a result, physicists received a “fantastic abundance” of xenon disturbances. In addition to 232 expected outbreaks, as many as 53 were recorded!
Something strange is definitely happening inside the xenon tank. But what exactly?
Researchers say there are three possible explanations. Let’s get rid of the boring first: it may just be a random source of background noise. The signal is consistent with tritium impurities in the reservoir, and only a few tritium atoms per 10 septillion (!) Xenon atoms are needed to create an imbalance. Unfortunately, not a single tool is sensitive enough to detect such insignificant levels of tritium in several tons of xenon, so this version cannot be ruled out.
Fortunately, the other two ideas are much more interesting. The team says that a hypothetical elementary particle called an axion is best suited as a source of disturbances. The concept of these particle was first proposed in the 1970s. If axions had a certain mass, then they could explain the oddities that we attribute to dark matter.
Although these specific solar axions would not be a candidate for “dark matter”, if this hypothesis is confirmed, the experiment will be the first in the history of science confirmed evidence of the discovery of any kind of axions as such. This in itself would be an extremely significant discovery.
The third explanation is that these signals come from previously unknown neutrino properties. These ultralight elementary particles are everywhere and rarely interact with another substance, but still sometimes they do. If neutrinos interact with xenon, they have a greater magnetic moment than the one described by the standard model of particle physics. If this theory turns out to be true, then we will need to make adjustments to the usual physical models.
The team claims that the theory of solar axions is currently the leader. The next phase of the experiment involves a three-fold increase in xenon mass with a general decrease in background “noise” – so we can find out the answer very soon.