We report the first direct measurement of the nuclear electron capture (EC) decay Q-value of 7Be →7Li via high-precision Penning trap mass spectrometry (PTMS). This was performed using the LEBIT Penning trap located at the National Superconducting Cyclotron Laboratory/Facility for Rare Isotope Beams (NSCL/FRIB) using the newly commissioned Batch-Mode Ion-Source (BMIS) to deliver the unstable 7Be+ samples. With a measured value of QEC = 861.963(23) keV this result is also three times more precise than any previous determination of this quantity. This improved precision, and accuracy of the 7Be EC decay Q-value is critical for ongoing experiments that measure the recoiling nucleus in this system as a signature to search for beyond Standard Model (BSM) neutrino physics using 7Be-doped superconducting sensors.
@article{arxiv.2308.13379,
title = {First direct $^{7}$Be electron capture $Q$-value measurement towards high-precision BSM neutrino physics searches},
author = {R. Bhandari and G. Bollen and T. Brunner and N. D. Gamage and A. Hamaker and Z. Hockenbery and M. Horana Gamage and D. K. Keblbeck and K. G. Leach and D. Puentes and M. Redshaw and R. Ringle and S. Schwarz and C. S. Sumithrarachchi and I. Yandow},
journal= {arXiv preprint arXiv:2308.13379},
year = {2024}
}