A new mass value for 7Li

TL;DR

This paper reports a highly precise measurement of the 7Li atomic mass using Penning trap mass spectrometry, revealing a significant deviation from previous literature values, which impacts nuclear and atomic physics calibrations.

Contribution

The study provides a new, highly accurate mass value for 7Li, significantly improving precision and resolving discrepancies with previous measurements.

Findings

New 7Li mass value with 0.63 ppb uncertainty

Discrepancy of up to 14 sigma with previous data

Implications for nuclear charge radii and neutron halo measurements

Abstract

A high-accuracy mass measurement of 7Li was performed with the Smiletrap Penning trap mass spectrometer via a cyclotron frequency comparison of Li3+ and H2+. A new atomic mass value of 7Li has been determined to be 7.016,003,425,6,(45)u with a relative uncertainty of 0.63 ppb. It has uncovered a discrepancy as large as 14 sigma (1.1 micro u) deviation relative to the literature value given in the Atomic-Mass Evaluation AME 2003. The importance of the improved and revised 7Li mass value, for calibration purposes in nuclear-charge radii and atomic mass measurements of the neutron halos 9Li and 11Li, is discussed.