@article{fox_longland_marshall_chaves_2024, title={Resolution of 40Ca to Constrain Potassium in NGC 2419}, volume={132}, ISSN={["1079-7114"]}, url={https://doi.org/10.1103/PhysRevLett.132.062701}, DOI={10.1103/PhysRevLett.132.062701}, abstractNote={The globular cluster NGC 2419 was the first to exhibit a Mg-K anticorrelation, linked to hydrogen burning at temperatures between 80-260 MK. However, the key K-destroying reaction, ^{39}K(p,γ)^{40}Ca, has a large rate uncertainty in this range. We significantly constrain this rate with a high resolution ^{39}K(^{3}He,d)^{40}Ca study. We resolve the E_{r}^{c.m.}=154  keV resonance in ^{39}K+p for the first time, increasing the previous rate by up to a factor 13 and reducing its 1σ width by up to a factor of 42. Reaction network calculations for NGC 2419 suggest that this could lower temperatures needed to reproduce the Mg-K anticorrelation.}, number={6}, journal={PHYSICAL REVIEW LETTERS}, author={Fox, W. and Longland, R. and Marshall, C. and Chaves, F. Portillo}, year={2024}, month={Feb} }