Axions – the particles that make up dark matter have fewer and fewer hiding places
The latest analysis of measurements of the properties of ultracold neutrons has led scientists to surprising conclusions. An international team of physicists, which included Poles, has shown that axions, if they actually existed, would have to meet much stricter constraints dot. their masses, and their interactions with ordinary matter would be much weaker.
Measurement analysisoin the electrical properties of ultracold neutronsow was published in the „Physical Review X”. Wspohe authors of the publication are m.in. Krakow scientists from the Institute of Nuclear Physics of the Polish Academy of Sciences (IFJ PAN) and Jagiellonian University.
Axions are hypothetical subatomic particles, whichore can create dark matter. As expected, they have no electric charge or spin. They were named by an American physicist of Polish-Italian descent – Frank Wilczek, and the name itself comes from the brand name of a certain laundry detergent.
Dark matter, on the other hand, is also hypothetical matter, whichoThe ra, according to assumptions, does not emit or reflect light radiation, so it is very difficult to detect it. But its existence is betrayed by the gravitational effects it exerts, at least in this wayob scientists explain the anomalies in the rotation of galaxies and the motion of galaxies in clusters. Despite years of searching, its existence has not been confirmed. Scientists are still trying to figure out the exact nature of dark matter and what creates it. According to the scientistsow, dark matter accounts for about 27 percent of the. The balance of mass and energy of the Universe around us – alongside ordinary matter and dark energy (whichora is also a hypothetical form of energy).
„Theorists have constructed a whole zoo of models predicting the existence of more or less exotic particles that could account for the existence of dark matter. Amongod candidateow are m.in. axions. If they existed, these extremely light particles would interact with ordinary matter almost exclusively by gravity. Almost, because previous models have predicted that in certain situations the photon mowould turn into an axion, and this after some time would transform back into a photon. This hypothetical phenomenon was and is the basis of the famous experimentsow „shining through the wall”. In their experiments, scientists direct an intense beam of laser light at a thick obstacle, hoping that at least a few photons will turn into axions, whichory would penetrate the wall without major problemsow. After passing through the wall, someore axions could revert to becoming photons with characteristics exactly like the photons originally incident on the wall” – we read on the IFJ PAN website.
The aforementioned analysis was based on data collected in the nEDM (Electric Dipole Moment of Neutron) experiment. The researchers showed that axions, if they existed, would have to meet much stricter constraints on their mass and manner than previously thoughtoin interactions with ordinary matter.
syndromeoł scientistow has been conducting its research for more than a dozen years. Participating in the work of Dr. hab. Adam Kozela of the Institute of Nuclear Physics of the Polish Academy of Sciences (IFJ PAN) admitted that the researchers did not think there could be traces related to potential dark matter particles in the data they collected. – Only recently theorists have suggested this possibility – and we eagerly took the opportunity to verify hypotheses about the properties of axionow – explained Kozela.
The theoretical work mentioned by the scientist predicting the possibility of additional interaction axionow with nucleons (protons or neutrons) and gluons (particles that bond quarks into nucleons). These interactions, depending on the mass of the axionow, could result in smaller or larger perturbations of the nature of dipole oscillations momentarilyoin electric nucleonoin, or even entire atomsow.
Thanks to the research, scientists have managed to tighten 40 times the restrictions imposed by the theory on the axion interactionow with nucleons. In the case of potential interactions with gluons, the strictures have increased even more, more than a thousandfold. So if axions do exist – they have fewer and fewer places in current theoretical models in which toowhich could be hiding – reports IFJ PAN.
Sourceobackground: IFJ PAN, fot. NASA, ESA, STScI, CXC. The image shows the distribution of dark matter (in blue) in six galaxy clusters, reconstructed from Hubble Space Telescope images'a