Experts already considered the finding a sensation, even with the word “Nobel Prize”: In 2018, scientists involved in the “MiniBooNE” experiment at the US Fermilab Research Laboratory near Chicago unveiled a mysterious surplus of electron neutrinos in their measurements that did not fit the classic single standard model. elementary particles. But new data from the subsequent “MicroBooNE” experiment now shows: nothing. “The results either agree or are slightly below expectations of the neutron booster beam speed and no excess electron neutrinos are observed,” the research group writes in the current issue of “Physical Review Letters”. Goodbye Nobel Prize.
The “MiniBooNE” experiment, originally launched in 2002, was supposed to confirm the result of the LSND neutrino experiment at Los Alamos National Laboratory in the 1990s, in which too many electron neutrinos were measured for the first time. The finding was irritating at the time because there was no obvious explanation. Experts have therefore speculated that these may be “sterile” neutrinos that interact with matter even less than their relatives, electron, muon, and tau neutrinos, which are already shy. If that were to happen, physicists hoped and still hope, some unanswered questions in the universe could come close, such as the search for dark matter or even the world formula. And indeed, the enthusiasm in 2018 was great.
In such measurements, scientists study what is known as neutrino oscillations – a quantum mechanical phenomenon in which neutrinos constantly change into each other. This behavior was first observed in the 1960s, when scientists measured far fewer neutrinos emitted by the Sun than expected. However, it took decades and required a lot of experimental work to convincingly prove that these “missing” neutrinos did not disappear on their way to Earth, but simply turned into two other types of neutrinos.