December 22, 2024

How big is the alpha particle? Laser spectroscopy provides new results with record precision

How big is the alpha particle? Laser spectroscopy provides new results with record precision

The size of the alpha particle, the nucleus of the helium atom, has been measured more accurately than ever before. Results now indicate a size 1.67824(83) femtometers, which is 4.8 times more precise than previous measurements. The researchers used laser spectroscopy of exotic helium ions, where the electron is replaced by a 200 times heavier muon.