Proton radii of 4,6,8He isotopes from high-precision nucleon-nucleon interactions

TL;DR

This study uses high-precision nucleon-nucleon interactions within the no-core shell model to accurately calculate the proton radii of helium isotopes 4He, 6He, and 8He, providing theoretical predictions aligned with experimental data.

Contribution

It presents ab initio calculations of helium isotope radii using advanced NN interactions, offering new theoretical predictions and comparisons with experimental results.

Findings

Calculated 4He and 6He radii agree with experiments.

Predicted 8He radius is 1.88(6) fm.

Different NN potentials affect binding energies and radii accuracy.

Abstract

Recently, precision laser spectroscopy on 6He atoms determined accurately the isotope shift between 4He and 6He and, consequently, the charge radius of 6He. A similar experiment for 8He is under way. We have performed large-scale ab initio calculations for 4,6,8He isotopes using high-precision nucleon-nucleon (NN) interactions within the no-core shell model (NCSM) approach. With the CD-Bonn 2000 NN potential we found point-proton root-mean-square (rms) radii of 4He and 6He 1.45(1) fm and 1.89(4), respectively, in agreement with experiment and predict the 8He point proton rms radius to be 1.88(6) fm. At the same time, our calculations show that the recently developed nonlocal INOY NN potential gives binding energies closer to experiment, but underestimates the charge radii.