Scientists have found as many neutrinos pass through the Earth’s core

© Illustration RIA Novosti . Alina Planinata the artist presented, as neutrinos fly through the Earth’s centreScientists have found as many neutrinos pass through the Earth’s core© Illustration RIA Novosti . Alina Polyanina

. The observation of neutrinos of ultrahigh energies with the IceCube detector helped physicists figure out how many of these particles passes through the core of the Earth and prove that part of them is absorbed by the bowels of the planet, according to a paper published in the journal Nature.

«This discovery is extremely important for the reason that it showed that neutrinos of ultrahigh energies can interact and be absorbed by other forms of matter, in this case, the bowels of the Earth. We know that neutrinos of low energy can pass through anything, and although we expected that high energy particles will behave differently, and to prove it we had not been able to,» said Doug Cowen (Cowen Doug) from the University of Pennsylvania in Philadelphia (USA).

The neutrino telescope IceCube is the world’s largest Observatory designed to study fluxes of neutrinos and muons of cosmic origin. It is located at the Antarctic station Amundsen-Scott, South pole of the Earth. The construction of the Observatory began in 2005 and was completed in December 2010. The main task of the detector — detection of the main sources of neutrinos in space.

One of the distinguishing features of IceCube is that the detector may monitor the neutrino in a very wide energy range, from space analogues of the thin particles can be obtained even by using terrestrial nuclear reactors and accelerators of matter to neutrinos of ultrahigh energies get close to the so-called limit Grayzena-Zatsepin-Kuzmin.

This word scientists understand the amount of energy that can have a neutrino or cosmic ray, moving towards the Earth from distant galaxies and other objects in space. Corpuscles, «violate» this limit will begin to interact with the microwave «echo» of the Big Bang, forming pions and other charged particles and lose energy. Today, physicists are arguing fiercely about whether neutrinos and other particles do not comply with this limit, and data from IceCube can help resolve this debate.

The standard model of physics, as noted by Cowen, moreover, predicts that neutrinos will not differ in this respect from other cosmic rays and elementary particles – the probability of their interaction with other forms of matter must increase as it approaches this limit.

On the other hand, despite this growth, it will remain extremely low, and the traces of the interaction of particles can be seen only if the neutrinos will pass through the multi-kilometer layer of very dense matter. IceCube can solve this problem, since it can observe the particles passing the entire thickness of the planet, and to determine the direction from which they came.

To search for the answer to this question scientists have used a simple observation of high energy neutrinos to interact with matter more often than low neutrino energies. Therefore, the number of such particles in IceCube from the North pole and flew through the Earth’s core, will be significantly less than from the equator and «sides» of the planet.

Following this idea, the researchers analyzed data gathered by the IceCube in its first year of operation for which the detectors have recorded about 10 thousand of neutrinos that passed through the detector from the «center» of the planet. After studying their properties, scientists estimate the number and proportion of high and low neutrino energies flew through the Earth’s core and outskirts of the planet, and compared them with each other.

As it turned out, the predictions of the Standard model was correct – the fraction of neutrinos that passed through the center of the planet, significantly fell with increasing energy of the particles. Comparing these values, Cohen and his colleagues calculated the rate at which neutrinos are «getting fatter,» the growth energy.
The calculation results almost completely coincided with what the classical theory says that casts doubt on the idea of the existence of «extra» dimensions, or exotic vectors of interactions between leptons and quarks.

«After upgrading IceCube, we will hold a new series of measurements that will help us to get rid of the errors and to reach a higher energy. When we reach this level we will be able to see how the absorption of neutrinos affects the behavior of matter at the Earth’s core and electromagnetic properties,» concludes Spencer Klein (Spencer Klein) from the University of California at Berkeley (USA).