Physicists spot a new class of neutrinos from the sun
Neutrinos spit out by the main processes that power the sun are finally accounted for, physicists report. Two sets of nuclear fusion reactions predominate in the sun’s core and both produce the lightweight subatomic particles in abundance. Scientists had previously detected neutrinos from the most prevalent process. Now, for the first time, neutrinos from the second set of reactions have been spotted, researchers with the Borexino experiment said June 23 in a talk at the Neutrino 2020 virtual meeting. “With this outcome, Borexino has completely unraveled the two processes powering the sun,” said physicist Gioacchino Ranucci of Italy’s National Institute for Nuclear Physics in Milan. In the sun’s core, hydrogen fuses into helium in two ways. One, known as the proton-proton chain, is the source of about 99 percent of the star’s energy. The other group of fusion reactions is the CNO cycle, for carbon, nitrogen and oxygen — elements that allow the...