## Precision mass measurements of neutron-rich neodymium and samarium isotopes and their role in understanding rare-earth peak formation

### R. Orford, N. Vassh, J. Clark, G. C. McLaughlin, M. Mumpower, G. Savard, R. Surman, A. Aprahamian, F. Buchinger, M. T. Burkey, D. A. Gorelov, T. Y. Hirsh, J. W. Klimes, G. E. Morgan, A. Nystrom, K. S. Sharma

Published PRL 120, 262702 (2018)

The Canadian Penning Trap mass spectrometer at CARIBU was used to measure the masses of eight neutron-rich isotopes of Nd and Sm. These measurements are the first to push into the region of nuclear masses relevant to the formation of the rare-earth abundance peak at A$\sim$165 by the rapid neutron-capture process. We compare our results with theoretical predictions obtained from reverse-engineering'' the mass surface that best reproduces the observed solar abundances in this region through a Markov Chain Monte Carlo technique. Our measured masses are consistent with the reverse-engineering predictions for a neutron star merger wind scenario.

LA-UR-18-22871

## Mail

Matthew Mumpower
Los Alamos National Lab
MS B283
TA-3 Bldg 123
Los Alamos, NM 87545