Muonic atoms unlock new possibilities in nuclear physics

A team at the UQ School of Mathematics and Physics has combined theory and experiments to show that nuclear polarisation does not limit studies of muonic atoms.

Co-author Dr Odile Smits said the finding provides a clear path for using muonic atoms to better understand the magnetic structure of the nucleus.

"Muonic atoms are really fascinating!" Dr Smits said.

"A muon is a heavy version of the electron and can be produced by cosmic rays or in the lab.

"They can orbit the nucleus just like electrons, forming muonic atoms, but because they are much closer to the nucleus, they see its structure in far greater detail."

Experiments using muonic atoms have been hindered by uncertainty over how nuclear polarisation affects hyperfine structure, which is a small energy splitting within atoms.

Nuclear polarisation distorts the shape of the nucleus, in a similar way to how the moon creates tides on Earth.

"Our work has shown that the nuclear polarisation effect in muonic atoms is far smaller than previously considered," Dr Smits said.

The team was led by UQ's Associate Professor Jacinda Ginges who said the breakthrough removed a major barrier to studying muonic atoms.

"This opens the way for new experiments that will deepen our understanding of nuclear structure and fundamental physics."

The team worked with Dr Natalia Oreshkina at the Max Planck Institute for Nuclear Physics in Heidelberg, Germany, who confirmed the results with independent calculations.

The UQ finding will be a stimulus for new experiments with muonic atoms such as at the Paul Scherrer Institute in Zurich where a research program is underway to study these exotic atoms in greater detail.