Key $^{19}$Ne states identified affecting $\gamma$-ray emission from $^{18}$F in novae
| Autor: | Hall, M. R., Barbadian, D. W., Baugher, T., Lepailleur, A., Pain, S. D., Ratkiewicz, A., Ahn, S., Allen, J. M., Anderson, J. T., Ayangeakaa, A. D., Blackmon, J. C., Burcher, S., Carpenter, M. P., Cha, S. M., Chae, K. Y., Chipps, K. A., Cizewski, J. A., Febbraro, M., Hall, O., Hu, J., Jiang, C. L., Jones, K. L., Lee, E. J., O'Malley, P. D., Ota, S., Rasco, B. C., Santiago-Gonzalez, D., Seweryniak, D., Sims, H., Smith, K., Tan, W. P., Thompson, P., Thornsberry, C., Varner, R. L., Walter, D., Wilson, G. L., Zhu, S. |
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| Rok vydání: | 2019 |
| Předmět: | |
| Zdroj: | Phys. Rev. Lett. 122, 052701, 2019 |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1103/PhysRevLett.122.052701 |
| Popis: | Detection of nuclear-decay $\gamma$ rays provides a sensitive thermometer of nova nucleosynthesis. The most intense $\gamma$-ray flux is thought to be annihilation radiation from the $\beta^+$ decay of $^{18}$F, which is destroyed prior to decay by the $^{18}$F($p$,$\alpha$)$^{15}$O reaction. Estimates of $^{18}$F production had been uncertain, however, because key near-threshold levels in the compound nucleus, $^{19}$Ne, had yet to be identified. This Letter reports the first measurement of the $^{19}$F($^{3}$He,$t\gamma$)$^{19}$Ne reaction, in which the placement of two long-sought 3/2$^+$ levels is suggested via triton-$\gamma$-$\gamma$ coincidences. The precise determination of their resonance energies reduces the upper limit of the rate by a factor of $1.5-17$ at nova temperatures and reduces the average uncertainty on the nova detection probability by a factor of 2.1. Comment: 6 pages, 4 figures |
| Databáze: | arXiv |
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