Laser Spectroscopic Determination of the 6He Nuclear Charge Radius

TL;DR

This study uses laser spectroscopy on trapped 6He atoms to precisely measure its isotope shift and determine its nuclear charge radius independently of nuclear models, providing critical data for nuclear structure theories.

Contribution

First direct, model-independent measurement of 6He nuclear charge radius using laser spectroscopy on individual atoms in a magneto-optical trap.

Findings

Measured isotope shift of 43,194.772 MHz with high precision.

Determined 6He nuclear charge radius as 2.054 +/- 0.014 fm.

Results test and inform nuclear structure calculations for halo nuclei.

Abstract

We have performed precision laser spectroscopy on individual 6He (t1/2 = 0.8 s) atoms confined and cooled in a magneto-optical trap, and measured the isotope shift between 6He and 4He to be 43,194.772 +/- 0.056 MHz for the 2 3S1 - 3 3P2 transition. Based on this measurement and atomic theory, the nuclear charge radius of 6He is determined, for the first time in a method independent of nuclear models, to be 2.054 +/- 0.014 fm. The result is compared with the values predicted by a number of nuclear structure calculations, and tests their ability to characterize this loosely bound, halo nucleus.