Physicists have analyzed the possible mechanisms for the absorption of dark matter particles, and showed that such reactions can register existing detectors. This gives the possibility of adapting a number of existing experiments to search for hypothetical particles and to obtain new constraints on their parameters, almost without additional costs. The text of the paper published in the journal Physical Review Letters.
Dark matter is a hypothetical form of matter that does not participate in electromagnetic interaction. For the first time about its existence, scientists have started talking in the beginning of the last century. Then the researchers found that galaxies and galaxy clusters do not have enough ordinary mass to move with the observed speed, you need an invisible component of matter that multiplies gravity. Since then, physicists have obtained many experimental and theoretical evidence for the existence of dark matter (more about this you can read in our interview with astrophysicist Andrei Doroshkevich). Today it is believed that its mass in the Universe is about five times greater than the mass of visible matter. Despite this, attempts to directly register dark matter particles yet weren’t crowned with success.
The American research team from the National laboratory behalf of the Lawrence Berkeley and University of California, under the leadership of Jeff Dror (Dror Jeff) introduced a new method of searching of the hypothetical particles. The authors focused on the reactions of absorption, in contrast to scattering, in which there is an exchange only of kinetic energy, in such processes the incident particle passes the target (usually the atomic nucleus) and its rest energy. The reaction can be detected by its — products in the particles produced in the collision. Their characteristics are measured by special detectors, and then, using the conservation laws, determine the type of the incident particle and its properties.
The researchers examined two kinds of reactions: in one case, the product becomes a neutrino and the other beta-particle (i.e. electron or positron). Thus for the considered targets, the two processes cannot occur spontaneously: for their course need more energy. The latter allows to exclude erroneous signals: in such circumstances, the registration of neutrinos or beta particle detector ensures that the target that was hit, and it is only necessary to set the type of the incident particle.
According to the study, the authors found that in the reactions with emission of neutrinos, which take place with the participation of dark matter particles, the core-target acquires a well-defined energy values. This will allow in the future easy to filter data — that is, to reduce the background and improve the sensitivity of the experiments. For processes involving beta-particle physics predicted a chain of subsequent reactions, which accompanies the birth of a number of known particles. Thus, to detect the absorption also becomes much easier. In addition, the researchers concluded that the search for dark matter using new method it is possible to use existing detectors. Their sensitivity allows if not to detect hypothetical particles, then at least to obtain important constraints on their parameters that will help in the further experiments. Thus, in this area it is possible to achieve significant progress, spending little effort for the adaptation of plants.
Earlier we wrote about how the hypothesis of superfluid dark matter is not withstood experimental testing and how to assemble a detector of elementary particles with their hands.