An analysis of the reaction 39K(d, α)37Ar on the basis of the statistical model

Naudé, W. J.; Bottega, A.; McMurray, William

doi:10.1016/0375-9474(68)90284-4

Cited by 12 publications

(1 citation statement)

References 30 publications

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“…The observation of these structures is also in agreement with previous work in the literature using the 40 Ar(p,n), (p,p), and (p,α) reactions [15,23] that report on the superposition of the two types of contributions. Statistical fluctuations are expected in compound nuclear reactions that proceed via highly-excited overlapping states in the compound system and are in agreement with various other studies of nuclear reactions in this mass region where statistical fluctuations of the partial cross-sections were reported in literature [25][26][27].…”

Section: Resultssupporting

confidence: 91%

Constraining the destruction rate of $^{40}$K in stellar nucleosynthesis through the study of the $^{40}$Ar(p,n)$^{40}$K reaction

Gastis,

Perdikakis,

Dissanayake

et al. 2020

Preprint

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Background: 40 K plays a significant role in the radiogenic heating of earth-like exoplanets, which can affect the development of a habitable environment on their surfaces. The initial amount of 40 K in the interior of these planets depends on the composition of the interstellar clouds from which they formed. Within this context, nuclear reactions that regulate the production of 40 K during stellar evolution can play a critical role. Purpose: In this study, we constrain for the first time the astrophysical reaction rate of 40 K(n,p) 40 Ar, which is responsible for the destruction of 40 K during stellar nucleosynthesis. We provide to the nuclear physics community high-resolution data on the cross-section and angular distribution of the 40 Ar(p,n) 40 K reaction. These are important to various applications involving 40 Ar. The associated reaction rate of the 40 Ar(p,n) 40 K process addresses a reaction rate gap in the JINA REACLIB database in the region of intermediate-mass isotopes Methods: We performed differential cross-section measurements on the 40 Ar(p,n) 40 K reaction, for six energies in the center-of-mass between 3.2 and 4.0 MeV and various angles between 0 • and 135 • . The experiment took place at the Edwards Accelerator Laboratory at Ohio University using the beam swinger target location and a standard neutron time-of-flight technique. We extracted total and partial cross-sections by integrating the double differential cross-sections we measured. Results: The total and partial cross-sections varied with energy due to the contribution from isobaric analog states and Ericson type fluctuations. The energy-averaged neutron angular distributions were symmetrical relative to 90 • . Based on the experimental data, local transmission coefficients were extracted and were used to calculate the astrophysical reaction rates of 40 Ar(p,n) 40 K and 40 K(n,p) 40 Ar reactions. The new rates were found to vary significantly from the theoretical rates in the REACLIB library. We implemented the new rates in network calculations to study nucleosynthesis via the slow neutron capture process, and we found that the produced abundance of 40 K is reduced by up to 10% compared to calculations with the library rates. At the same time, the above result removes a significant portion of the previous theoretical uncertainty on the 40 K yields from stellar evolution calculations. Conclusions: Our results support that the destruction rate of 40 K in massive stars via the 40 K(n,p) 40 Ar reaction is larger compared to previous estimates. The rate of 40 K destruction via the 40 K(n,p) 40 Ar reaction now has a dramatically reduced uncertainty based on our measurement. This result directly affects the predicted stellar yields of 40 K from nucleosynthesis, which is a critical input parameter for the galactic chemical evolution models that are currently employed for the study of significant properties of exoplanets.

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