We have studied natural parity states in 26 Mg via the 22 Ne( 6 Li, d) 26 Mg reaction. Our method significantly improves the energy resolution of previous experiments and, as a result, we report the observation of a natural parity state in 26 Mg. Possible spin-parity assignments are suggested on the basis of published γ -ray decay experiments. The stellar rate of the 22 Ne(α, γ ) 26 Mg reaction is reduced and may give rise to an increase in the production of s-process neutrons via the 22 Ne(α, n) 25 Mg reaction.

Type I X-ray bursts are violent stellar events that take place on the H/Herich envelopes of accreting neutron stars. We have investigated the role played by uncertainties in nuclear processes on the nucleosynthesis accompanying these explosive phenomena. Two different approaches have been adopted, in the framework of post-processing calculations. In the first one, nuclear rates are varied individually within uncertainties. Ten different models, covering the characteristic parameter space for these stellar events, have been considered. The second, somewhat complementary approach involves a Monte Carlo code in which all

This is an accepted version of a paper published in Nature. This paper has been peer-reviewed but does not include the final publisher proof-corrections or journal pagination.Citation for the published paper: Hinke, C., Boehmer, M., Boutachkov, P., Faestermann, T., Geissel, H. et al. (2012) "Superallowed Gamow-Teller decay of the doubly magic nucleus 100 Sn" Nature, 486 (7403): [341][342][343][344][345] Access to the published version may require subscription.

We have measured proton and ␣-particle branching ratios of states formed using the 19 F͑ 3 He, t͒ 19 Ne * reaction at a beam energy of 25 MeV. These ratios have a large impact on the astrophysical reaction rates of 15 O͑␣ , ␥͒ 19 Ne, 18 F͑p , ␥͒ 19 Ne, and 18 F͑p , ␣͒ 15 O, which are of interest in understanding energy generation in x-ray bursts and in interpreting anticipated ␥-ray observations of novae. We detected decay protons and ␣ particles using a silicon detector array in coincidence with tritons measured in the focal plane detector of our Enge split-pole spectrograph. The silicon array consists of five strip detectors of the type used in the Louvain-Edinburgh Detector Array, subtending angles from 130°to 165°with Ϸ14% lab efficiency. The correlation angular distributions give additional confidence in some prior spin-parity assignments that were based on ␥ branchings. We measure ⌫ p / ⌫ = 0.387± 0.016 for the 665 keV proton resonance, which agrees well with the direct measurement of Bardayan et al.