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arXiv · 0911.0303

Gamow-Teller strength distributions at finite temperatures and electron capture in stellar environments

Alan A. Dzhioev·A. I. Vdovin·V. Yu. Ponomarev·J. Wambach·K. Langanke·G. Martínez-Pinedo
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Abstract

We propose a new method to calculate stellar weak-interaction rates. It is based on the Thermo-Field-Dynamics formalism and allows the calculation of the weak-interaction response of nuclei at finite temperatures. The thermal evolution of the GT$_+$ distributions is presented for the sample nuclei $^{54, 56}$Fe and ~$^{76,78,80}$Ge. For Ge we also calculate the strength distribution of first-forbidden transitions. We show that thermal effects shift the GT$_+$ centroid to lower excitation energies and make possible negative- and low-energy transitions. In our model we demonstrate that the unblocking effect for GT$_+$ transitions in neutron-rich nuclei is sensitive to increasing temperature. The results are used to calculate electron capture rates and are compared to those obtained from the shell model.

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Alan A. Dzhioev, A. I. Vdovin, V. Yu. Ponomarev, J. Wambach, K. Langanke, G. Martínez-Pinedo. 2009-11-02. Gamow-Teller strength distributions at finite temperatures and electron capture in stellar environments. https://doi.org/10.1103/physrevc.81.015804

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