New insights into neutrino interactions

Research conducted at Hokkaido University has revealed that elusive particles called neutrinos can interact with photons, the fundamental particles of light and other electromagnetic radiation, in ways never before discovered. The findings by Kenzo Ishikawa, professor emeritus at Hokkaido University, and his colleague Yutaka Tobita, lecturer at Hokkaido University of Science, were published in the journal. Physics is open.

“Our results are important for understanding quantum mechanical interactions of some fundamental particles of matter,” says Ishikawa. “It may also help reveal details of currently poorly understood phenomena in the Sun and other stars.”

Neutrinos are one of the most mysterious fundamental particles of matter. They are extremely difficult to study because they barely interact at all with other particles. They are electrically neutral and have almost no mass. However, they are so abundant, that vast numbers are constantly flowing from the Sun and passing through the Earth, and indeed through ourselves, with little effect. Learning more about neutrinos is important to test and perhaps improve our current understanding of particle physics, known as the Standard Model.

“Under normal ‘classical’ conditions, neutrinos would not interact with photons. However, we have revealed how neutrinos and photons can be induced to interact in regular magnetic fields of very large scale – up to 10,” Ishikawa explains.³ km – exists in the form of a substance known as plasma, which is found around stars.” Plasma is an ionized gas, meaning that all of its atoms have gained either an increase or loss of electrons, making them negatively or positively charged ions, rather than neutral atoms that It can exist in everyday conditions on Earth.

The interaction described by the researchers involves a theoretical phenomenon called the electroweak Hall effect. This is an interaction between electricity and magnetism under extreme conditions in which two of nature’s fundamental forces – the electromagnetic forces and the weak forces – combine into the electroweak force. It is a theoretical concept, expected to apply only in the very high-energy conditions of the early universe or during collisions in particle accelerators.

The research produced a mathematical description for this unexpected interaction between a neutrino and a photon, known as a Lagrange. This describes everything that is known about the energy states in the system.

“In addition to contributing to our understanding of fundamental physics, our work may also help explain the so-called solar corona heating puzzle,” says Ishikawa. “This is a long-standing mystery regarding the mechanism by which the Sun’s outer atmosphere – the corona – is at a much higher temperature than the Sun’s surface. Our work shows that the interaction between neutrinos and photons releases energy that heats the Sun’s atmosphere. The solar corona.”

“We now hope to continue our work in search of deeper insights, especially regarding energy transfer between neutrinos and photons under these extreme conditions,” says Ishikawa.