We may have just taken a big step towards understanding dark matter

We may have just taken a big step towards understanding dark matter

A trillion of them pass through our body every second. Their name? Neutrinos. These elementary particles, the only ones to be electrically neutral, are extremely discreet: in an article which has just appeared, Popular Science even describes them as “shy”due to their tendency not to interact.

Neutrinos are not present in atoms, and they are elusive, sometimes oscillating between different states (or “flavors”). We know three of them: electronic, muonic and tauic flavors. Anyway until now.

The article in Popular Science is not devoted to their timidity, but to new experiments carried out by Russian scientists in the Caucasus region. These could well lead to new discoveries on these particles that are so difficult to understand, but a more complete mastery of which could make it possible to explore lands that are still too little explored in physics.

This Russian team, which published its results on June 9 in this article and in this one, claims to have found a new neutrino profile, even more difficult to detect.

A not insignificant finding, since it could quite simply help explain why we cannot see dark matter, this matter which is supposed to be distributed throughout the universe, and which we know that it is made up of elementary particles – but not protons, neutrons or electrons.

New flavor

For Ben Jones, a neutrino physicist at the University of Texas at Arlington, it’s “probably one of the most important results of the last five years in neutrino physics”. It could indeed confirm what the scientific community had been sensing for at least twenty-five years, namely a fourth flavor of neutrinos.

During experiments carried out at the end of the last century, neutrinos sometimes seemed to have simply disappeared, as if to contradict the famous “Nothing is lost, nothing is created, everything is transformed” attributed to Lavoisier.

In reality, these disappearances, which were not, were probably explained by a passage of neutrinos towards a hidden fourth flavor, the “sterile neutrino”, whose existence has apparently just been proven by Russian researchers – even if that remains to be confirmed.

First good news: it would explain why so many neutrino experiments ended with a question mark. “Either these experiments were failed, exposes Ben Jones, or something more interesting and weirder was happening, with a different signature.” We now have a small idea of ​​the answer.

The experiments known as BEST (for “Baksan Experiment on Sterile Transitions”) were conducted more than a mile and a half below the bed of the Baksan River in Russia.

They are only in their infancy, but more than promising beginnings: they confirm certain anomalies noted about neutrinos and must be further deepened and validated. Neither the hypothesis of the existence of sterile neutrinos, nor that of the responsibility of the latter in the strange behavior of neutrinos during past experiments, have for the moment been confirmed.

But if these theories end up being definitively certified, it would open a new and immense door to understanding our universe: sterile neutrinos could well constitute the main component of dark matter, this so fascinating matter of which we still know so little.