TITAN mass measurements of neutron-rich Cs, Ba and r-process lanthanide abundances

2026/08/05 by T. -H. Yeh, J. D. Cardona, Y. Wang +26
Physics and Astronomy · #nucl-th #nucl-ex

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arxiv created 2026/08/05 · arxiv updated 2026/08/07

Abstract

We present measurements for the masses of five neutron-rich isotopes, ^149-151Cs and ^{151, 152}Ba, probed for the first time by TITAN at TRIUMF with time-of-flight measurement techniques. We propagate these masses to the nuclear reaction and decay data required for the simulation of the rapid neutron capture process (r-process) nucleosynthesis in neutron star mergers. We show that these neutron-rich masses affect the abundance predictions near mass number A∼148-152 corresponding to lanthanide element abundances at Z=60, 62 and 63. We demonstrate that these new TITAN masses smooth out the odd-even effect in isotopic abundance predictions near A∼150 in both fission cycling astrophysical conditions and conditions that do not reach actinides. We further show that these new masses adjust how fission fragments settle into place when forming the final abundances, and consider the effect on comparisons with stellar abundance ratios such as [Ag/Eu], [Sm/Eu], and [Nd/Eu].

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