hard particles dark matter They may be hiding deep in the heart of the Sun, and researchers have discovered that we can use a detector buried in the Antarctic ice sheet to find them. Dark matter is the inevitable result of decades of cosmological observations. Everything from the rotation speed of stars in galaxies to the growth of the largest structures in the universe points to the existence of a type of particle currently unknown to physics that rarely interacts with light or normal matter despite its strong gravitational pull. throughout the universe.

So far we don’t know who this dark matter particle is. Therefore, due to the relative lack of solid evidence, theorists have put forward dozens of suggestions for what dark matter might be. According to some of these hypotheses, dark matter interacts with ordinary matter; but very rarely, in the densest cosmic environment.

In a paper published in the Preprints Database, researchers suggested that the perfect place for this type of dark matter to naturally accumulate is the Sun’s interior. arXiv August 23, but not yet reviewed. The Sun’s core is incredibly dense; It is 20 times denser than iron. And the Sun has been orbiting the center of the Milky Way since its birth about 4.5 billion years ago. For all these billions of years, our star has been floating in an invisible sea of ​​dark matter particles that are thought to make up most of our galaxy.

Even if interactions between dark matter and normal matter are extremely rare, the density of the Sun’s core – combined with its extreme age – means that there is plenty of time for one of its particles to interact with dark matter. These interactions will deplete the dark matter particles’ energy and slow them down until they settle deep into the Sun’s core.

The IceCube laboratory at the South Pole is illuminated by star trails in this photo taken in July 2015. (Image: IceCube Collaboration)

And these dark matter particles can stay there for a second or a billion years until they interact with another normal matter particle in the dense medium. When this happens, a dark matter particle, if heavy enough, can collapse into a shower of more familiar types of particles. Most of these particles will remain trapped in the nucleus and bounce around in the endless frenzy of their fiery environment. However, a type of particle, the neutrino, manages to escape from the sun.

neutrino It’s almost like dark matter. They are incredibly light (the lightest known particles), have no electrical charge, and interact with almost nothing. To detect neutrinos, scientists need to build giant laboratories. The largest of these detectors is IceCube, which uses an entire cubic kilometer (0.24 cubic miles) of the Antarctic ice sheet as a test chamber. When neutrinos collide with water molecules, they create a shower of particles and light that can be detected by strings embedded in the ice.

The Sun naturally produces neutrinos as a result of reactions. synthesis. But in a new paper, researchers believe that if dark matter accumulates inside the solar core and these dark matter particles evaporate into a shower of ordinary particles, including neutrinos, then we might expect to see more high-energy neutrinos coming from the sun. in the IceCube detection array.

However, current neutrino detection rates from the sun are consistent with normal fusion reactions; This means that if dark matter exists and is currently accumulating in the Sun, these dark matter particles are extremely incapable of destroying normal matter. This lack of detection places significant constraints on the properties of dark matter particles.

In particular, these are the strongest constraints imposed on theories of massive dark matter, and all the data is just sitting there collected for other purposes, the researchers said. Instead of developing new and expensive experiments to investigate dark matter, they said, we should find clever ways to use existing experiments because we never know what surprises might arise. Source