They prove that neutrino models, essential to understanding the origin of the universe, need to be improved.

O neutrinos, one of the most elusive particles in the universe, may hold the key to finally solving the mystery of our planet’s origins. universe, dominated by matter, and preparations are already underway for large, multi-million-euro experiments to reveal the secrets of these particles, explains a statement from the Thomas Jefferson Laboratory of the US Department of Energy.

These subatomic particles are ubiquitous, generated in large numbers by stars across the universe. Although common, these “shy particles” rarely interact with matter, making them very difficult to study.

Your measurements depend on Models that predict like the neutrinos interact with the nuclei of atoms: neutrinos cannot be detected directly, but can be detected indirectly if the particles that are emitted when they interact with atomic nuclei are observed.

Now, a group of physicists publishes a study in the journal Nature where he is warned about the need to make “important updates” to the models of these particles so that experiments can achieve high precision results.

This is the conclusion of an investigation carried out at the Thomas Jefferson accelerator facility: “The result is, in fact, to point out that there are aspects of energy reconstruction methods and models that need to be improved”So that ongoing projects reach the necessary precision to achieve the expected objectives.

According to the authors, a better understanding of how they relate to matter is necessary to get the most out of future experiments.

There is a phenomenon, which is known as neutrino oscillation, in which neutrinos change from one type to another. “It’s interesting to study because it’s not well known,” he says. Mariana Khachatryan, study co-author and associate researcher at Florida International University (USA).

One way to study this oscillation is to build giant, ultrasensitive detectors to measure neutrinos underground.

“The way physicists do this is by measuring all the particles that come out of the neutrinos’ interaction with the nuclei and reconstructing the incoming neutrino energy to learn more about them, their oscillations and measure them very, very accurately . “, he details on his part Adi Ashkenazi, from Tel Aviv University (Israel).

To do this, a theoretical simulation called Genie, which allows physicists to infer the energies of incoming neutrinos. Genie is an amalgamation of many models that help to reproduce certain aspects of the interactions between neutrinos and nuclei.

the help of the electron

Since so little is known about them, it’s difficult to test Genie directly, which is why this research used “a humble particle” that physicists know a lot more about: a electron, as they both have a lot in common. “We use electron studies to validate models of interaction between neutrinos and nuclei,” says Khachatryan.

The team used a version of Genie based on electron scattering (e-GENIE) to test the same algorithms that neutrino researchers will use.

If the model doesn’t work for electrons, which we’re talking about the simplest case, it will never work for neutrinos

Afroditi Papadopoulou, study co-author

“We use exactly the same simulation that neutrino experiments use and we use the same corrections,” he explained. Aphroditi Papadopoulou, also a signatory to the study, “and if the model does not work for electrons, in which we are talking about the most simplified case, it will never work for neutrinos”.

However, when Genie was used to model the data, it did not perform as expected: “this can skew the results of the neutrino wobble,” he warns.

According to the team, the goal is to achieve broad consensus between the data and the models, which will help ensure that the experiments DUNE (United States) and Hyper-Kamiokande (Japan) can achieve the expected high accuracy results.