The Mystery of the Cosmic Origin of Gold Revealed## Conversation with Claude

American physicists from the University of Tennessee conducted an experiment that shed light on one of the key processes responsible for the formation of heavy elements - such as gold and platinum - in the Universe. They managed to clarify exactly how unstable atomic nuclei decay and create new chemical elements in stars. The work was published in the journal Physical Review Letters (PRL).

When massive stars collide, explode, or collapse, a so-called r-process - rapid neutron capture - is triggered inside them. During this process, the nucleus absorbs dozens of neutrons in succession, becomes unstable, and eventually decays, transforming into more stable elements. This is exactly how, according to astrophysicists, gold, uranium, and other heavy substances appeared in the Universe. But the details of this process remained a mystery for a long time.

To look into its mechanics, a team of researchers led by Professor Robert Grzywacz and with the participation of graduate students Peter Dizzel and Jacob Googe used a rare isotope - indium-134. Its unstable nuclei were obtained at the ISOLDE facility at CERN using laser separation. When indium decays, isotopes of tin-134, tin-133, and tin-132 are formed, and it was in these transitions that scientists recorded three unique phenomena.

The main result is the world's first measurement of neutron energies in β-delayed double neutron emission. This rare type of decay occurs only in exotic nuclei that exist for fractions of a second. Measuring it proved extremely difficult: neutrons have no charge and scatter easily, making it difficult to determine their number and energy.

"This is really a big event," noted Professor Grzywacz. "Previously, no one could measure the energy of two neutrons emitted simultaneously. Now we have experimental data that opens up a completely new direction of research."

The obtained results will allow scientists to improve models of stellar catastrophes describing the origin of heavy elements, and to more accurately predict the properties of exotic nuclei that play a key role in cosmic chemistry.