Uncorrelated Nuclear Mass Uncertainties and r-process Abundance Predictions

Abstract

Nuclear masses have long been recognized as key nuclear physics inputs for calculations of rapid neutron capture, or r-process, nucleosynthesis. Here we investigate how uncorrelated uncertainties in nuclear masses translate into uncertainties in the final abundance pattern produced in r-process simulations. These uncertainties can obscure details of the abundance pattern that in principle could be used to diagnose the r-process astrophysical site. We additionally examine the impact of reductions of mass uncertainties that will come with new experiments.

Systematic and Statistical Uncertainties in Simulated r-Process Abundances due to Uncertain Nuclear Masses

“…These can be explored via Monte Carlo variations in nuclear masses. Preliminary versions of such studies [13] have focused on hot r-process scenarios, where the primary influence of the masses is through the neutron separation energies as they appear in the photodissociation rate calculations. Here we report on a preliminary mass Monte Carlo study of a cold merger tidal tail trajectory.…”

Propagation of Statistical Uncertainties of Skyrme Mass Models to Simulations of $r$-Process Nucleosynthesis

“…Past work in this area has either considered abundance pattern comparisons between distinct mass models, e.g. [17], or ranges of patterns that result from random, uncorrelated mass variations [14,18].…”

Masses and lifetimes for r-process nucleosynthesis: FRIB outlook

“…The nuclear network calculations used to estimate the nuclei produced in a merger and their associated radioactive heating rely on nuclear physics information-masses, reaction rates, β-decay and fission properties-for thousands of nuclei from the valley of stability to the neutron drip line [5,6]. Only a fraction of the needed data has be measured experimentally, leading to large uncertainties in predicted abundance patterns [4,[6][7][8][9] and radioactive heating estimates [10].…”

“…Neutron separation energies set the abundances along each isotopic chain while equilibrium holds and influence the individual neutron capture rates and photodissociation rates that are important once equilibrium fails. The r-process calculations proceed as in [6,8]. The baseline simulation uses AME2016 masses with FRDM2012 masses where experimental values are not available, NUBASE 2016 [14] β-decay rates with rates from [17] where experimental values are not available, and NONSMOKER [18] neutron capture rates.…”

“…In contrast, the same mass changes produce changes to neutron capture rates of factors of two to five and β-decay rates of factors of two to four [13]. Thus to capture the primary influence of masses for these astrophysical conditions, we update the neutron separation energies and photodissociation rates for each step as in [8]. The light green shaded region of Fig.…”