“(Phys.org, April 12, 2012) -- Nuclear physicists recently witnessed an atomic nucleus do something that nobody had ever seen one do before – two neutrons at the same time.
Emitting them, that is.
The experiment revealed a brand new form of nuclear decay, the process by which unstable atoms release energy and transform into more stable forms. But instead of emitting known patterns of radiation, the nucleus ejected two correlated neutrons simultaneously – a dineutron. Though physicists had long theorized about the existence of this form of decay, this was the first experiment to see the dineutron event in action.
“We have for the first time unambiguously observed dineutron decay and clearly identified it in beryllium-16,” said Artemis Spyrou, professor of nuclear physics.
The newly discovered dineutron decay mode joins the 15 other known forms of atomic decay, including double proton emission, double beta decay and double positron emission. The results hold promise to strengthen scientists’ understanding of the strong force that holds nuclei together and the processes taking place within neutron stars.
The researchers caught the act red-handed. Beryllium-16 is an unbound, unstable isotope with 4 protons and 12 neutrons that decays in less than a trillionth of a second. To produce the extremely short-lived nucleus, the physicists smashed a beam of boron-17 into a solid target, occasionally knocking out a proton and forming the desired beryllium-16…”