Scientists challenge fundamental spin-statistics assumptions in atomic collisions

Scientists challenge fundamental spin-statistics assumptions in atomic collisions
by Simon Mansfield
Sydney, Australia (SPX) Oct 31, 2024

Since the first X-ray image of a comet was taken in 1996, researchers have intensely studied charge exchange in collisions between highly charged ions and atoms or molecules, a process critical for astrophysical modeling. In simulating observed X-ray spectra, astrophysicists depend on precise atomic data, where spin statistics are traditionally considered a fundamental guideline.

A new study, however, has brought these foundational assumptions into question. Published in 'Physical Review Letters' on Oct. 22, research led by the Institute of Modern Physics (IMP) of the Chinese Academy of Sciences (CAS) has provided direct evidence that spin statistics may not hold in certain ion-atom charge exchange collisions. This finding could have implications across multiple fields where spin statistics are considered pivotal.

Conducted at the low-energy terminals of Lanzhou's Heavy Ion Research Facility, the experiment used a highly sensitive reaction microscope to observe collisions between neutral helium and C3+ ions. This microscope's high precision allows scientists to determine atomic states at the moment of electron capture, an advancement that has improved analysis accuracy over previous studies.

"The C3+ ion is ideal for this investigation as it remains in its ground state during the collision, allowing us to accurately analyze the mechanisms at play," explained Prof. ZHU Xiaolong from IMP, the study's lead author. "With the reaction microscope, we overcome challenges that hindered previous experiments."

Through a combination of experimental and theoretical methods, researchers directly measured spin-resolved cross-section ratios, providing a test for spin-statistics assumptions. The results showed a significant deviation from expected spin statistics at high-impact energies, where these assumptions were previously believed to be reliable.

Prof. MA Xinwen of IMP, a corresponding author, noted, "This discovery opens up new questions regarding electronic dynamics in fast collisions and the potential for quantum manipulation in atomic and molecular interactions."

Research Report:Direct Evidence of Breakdown of Spin Statistics in Ion-Atom Charge Exchange Collisions