Speaker
Description
S.V. Artemov1,2, N. Burtebayev1,3, S.B. Sakuta1,4, S.B. Igamov2, Maulen Nassurlla1,3, Marzhan Nassurlla1,K. Rusek5, F.Kh. Ergashev2, O.R.Tojiboev2, I.Ya. Son2, D.A. Issayev1,3
1 Institute of Nuclear Physics, 050032 Almaty, Kazakhstan
2 Institute of Nuclear Physics, 100214 Tashkent, Uzbekistan
3 Al-Farabi Kazakh National University, 050040 Almaty, Kazakhstan
4 National Research Center “Kurchatov Institute”, 123182 Moscow, Russia
5 Heavy Ion Laboratory University of Warsaw, PL-20-093 Warsaw, Poland
E-mail: igamov@inp.uz
It is generally accepted that the 12C nucleus is formed mainly by fusion of three α particles, 3α→12C through the Hoyle state (0+) with an excitation energy of 7.65 MeV, as the proton capture by the 11B nucleus at Ep < 100 keV has a small cross section for 12C formation in primary nucleosynthesis. However, the alternative pathways of its formation considered, for example, in the inhomogeneous Big Bang model [1] leading to radiative capture of a proton by the 11B nucleus, cannot be ignored. As noted in [1,2], in the processes of nucleosynthesis in proton-rich environment, the following chains of nuclear reactions may also be important:
…7Be(p,γ)8B(α,p)11C(e+ν)11B(p,γ)12C…
The direct measurements of the total S-factors of radiative capture on 12C, even at not too low energies, is a non-trivial experimental task, since it is necessary to measure the γ spectra of low-intensity high-energy γ-quanta (Eγ>10 MeV) and also high-energy cascade quanta [1]. Note that in the astrophysically significant energy region below 100 keV in the 11B+p system there are no resonances, and therefore, for extrapolating calculations of the total S-factors and reaction rates, it becomes very important to know the ANCs for bound states of the proton in the 12C nucleus, which can make a significant contribution to the total direct proton capture cross section.
The aim of this work is to calculate the astrophysical S-factor and the reaction rate 11B(p,γ)12C using the ANC square values for the ground (0+) and excited (2+) states of the 12C nucleus (where the experimental data are available), obtained from the analysis of the peripheral 11B(10B,9Be)12C proton transfer reaction.
The calculation of the astrophysical S factor of the 11B(p,γ)12C radiative capture reaction was carried out within the framework of the modified R-matrix method for transitions to the ground (0+) and 1-st exited (E=4.44 MeV, 2+) states of the 12C nucleus. This work also presents the results of the calculation of the reaction rate 11B(p,γ)12C based on the energy dependence of the S-factor at the astrophysical relevant temperatures.
References
1. J.J. He et al., Phys. Rev. C 93, 055804 (2016)
2. V. Guimaraes and C. A. Bertulani AIP Conf. Proc. 1245, 30 (2010)
| Section | Nuclear physics (Section 1) |
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