Radiative p11b capture at astrophysical energies

In the framework of the modified potential cluster model with forbidden states the possibility of describing the available experimental data on the total cross sections and astrophysical S-factor for p11B radiative capture to the ground state of 12C was treated at astrophysical energies.Comment: 10p., 4 fig., 30 ref. arXiv admin note: text overlap with arXiv:1312.427

Whether the excited cluster 14N* exists in 15O nucleus?

Within the modified potential cluster model with forbidden states effectively taking into account the Pauli Exclusion Principle the astrophysical S-factor of radiative p14N capture to 15O ground state has been calculated. The calculation was performed at the proton energy up to 5 MeV in the center of mass system (c.m.) with taking into account broad resonances up to 3.4 MeV in c.m. To explain reasonably the available experimental data it is required to admit the existence of 14N cluster in excited state 14N* with the excitation energy equal to 5.69 MeV and momentum JP = 1-. It is assumed that in this case the 4D1/2 state wave function of the p14N* clusters relative motion may be used. There was shown that it is succeeded to describe the S-factor of p14N capture in the resonance region only under the assumption that all low-lying resonances at 260(1/2+), 987(3/2+), 1447(1/2+), 2187(3/2+), and 3211(3/2+) keV in c.m. are the 4D1/2 and 4D3/2 scattering waves.Comment: 7p., 5 nsbl., 2 fig., 31 ref. arXiv admin note: text overlap with arXiv:0906.1097 by other author

New results for the astrophysical S-factor and reaction rate of radiative 3He4He capture

In the frame of modified potential cluster model based on the classification of orbital states by Young diagrams and revised interaction potential parameters for the bound states of 7Be in 3He4He cluster model with forbidden states the astrophysical S-factor for the radiative capture reaction has been calculated from the 10 keV. Obtained results S(23 keV) = 0.561 keV b reproduce the latest experimental data at 23 keV. Calculated and parametrized reaction rate is compared to some results known in the range of temperatures from 0.05 to 5 T9.Comment: 7p., 4 fig., 1 tab

The radiative neutron capture on 2H, 6Li, 7Li, 12C and 13C at astrophysical energies

The continued interest to the study of the radiative neutron capture on atomic nuclei is caused, on the one hand, by the important role of this process in the analysis of many fundamental properties of nuclei and nuclear reactions, and, on the other hand, by the wide use of the capture cross section data in the various applications of nuclear physics and nuclear astrophysics, and, also, by the analysis of the processes of primordial nucleosynthesis in the Universe. This review is devoted to description of the results obtained for the processes of the radiative neutron capture at thermal and astrophysical energies on certain light atomic nuclei. The consideration of these processes is done in the frame of the potential cluster model, the general principles of which and calculation methods were described earlier. The methods of usage of the obtained on the basis of the phase shift analysis intercluster potentials will be directly demonstrated for calculations of the radiative capture characteristics. The considered capture reactions are not a part of stellar thermonuclear cycles, but they get in the basic reaction chain of primordial nucleosynthesis, taken place in the time of the Universe formation.Comment: 52p., 14 fig., 10 tabl., 140 ref. arXiv admin note: substantial text overlap with arXiv:1201.1741, arXiv:1202.142

Influence of low-lying resonances on reaction rates for n10B capture

The possibility of description available experimental data for total cross section for reaction of the neutron capture on 10B at energies from 25.3 meV to 1.0 MeV was considered in the frame of the modified potential cluster model with forbidden states, classification of the orbital cluster states according to Young diagrams and taking into account the resonance behavior of phase shifts of the n10B elastic scattering. The obtained results agree with the experimental measurements. The calculated total cross sections are used for obtaining the reaction rate of the neutron capture on 10B at the temperature range from 0.01 to 10 T9. The reaction rate rises essentially at temperatures above 0.3 - 0.4 T9, conditioned by the resonances at the energy above 100 keV.Comment: 10 fig., 4 tabl., 16

Integer and half-integer channel spins for elastic scattering cross sections

We present the analytical expressions for the differential cross sections and independent partial amplitudes for elastic scattering of nuclear particles for channels with a spin value of 1/2, 1, 3/2, 2 and 5/2. The independent partial amplitudes are presented for arbitrary orbital angular momentum $l$ and taking into account spin-orbit splitting. The analytical expressions allow one to carry out full phase shift analyses using experimental data for differential cross sections for processes with channel spins 1/2, 1, 3/2, 2 and 5/2.Comment: 33 page

New Results for the p7Be-->8Bgamma Astrophysical S-factor from 10 keV to 5 MeV and Reactions Rate from 0.01 to 10 T9

The astrophysical S-factor for the process p7Be --> 8Bgamma of radiative capture by the 8B ground state is described up to 5 MeV, within the modified potential cluster model. The signatures of the S-factor resonances at 0.632, 2.18 and 3.36 MeV due to M1 and E2 transitions from the scattering of resonance 3P1, 3F3 and 3D2 waves to the ground 3P2 state are illuminated using total cross sections, astrophysical S-factors and reaction rates at temperatures from 0.01 to 10.0 T9. Experimental data on the S-factor are reproduced well in the range 100 keV to 3 MeV. The importance of the input of the 0.632 MeV resonance to the reaction rate is proved. Our calculations (performed in advance) confirm the latest data for the S-factor at 19 keV.Comment: 21p., 4 nab., 7 fig., 53 re

Radiative n11B capture accounting 21 and 430 keV resonances

In the framework of the modified potential cluster model the possibility of describing the available experimental data for the total cross sections for n11B radiative capture at thermal and astrophysical energies were considered with taking into account the 21 and 430 keV resonances

New Results for Neutron Radiative Capture on 10be at Energies from 25.3 meV to 10.0 meV

It is shown that in the framework of the modified potential cluster model we succeeded in correct describing the available experimental data for neutron radiative capture on 10Be total cross-sections at low, astrophysical and thermal energies. All interaction potentials for different partial waves are constructed by describing the basic characteristics of the bound states and spectra of final nucleus. Experimental data for the total cross-sections of the neutron radiative capture on 10Be were obtained by using known data for reduced probabilities of 11Be Coulomb dissociation.Comment: 8 fig., 6 tabl., 47 ref. 22

New results for radiative 3He(2H,gamma)5Li capture at astrophysical energy and its possible role in accumulation of 6Li at the BBN

Big Bang Nucleosynthesis (BBN) relevance reactions 3He(2H,{\gamma})5Li, 3H(3He,{\gamma})6Li, 5Li(n,{\gamma})6Li as a key to approach for scenario of 6Li formation are treated. The rates of reaction for these processes are analyzed. Comparison of the reactions rates and the prevalence of light elements leads to the assumption that the two-step process 2H + 3He --> 5Li + {\gamma} and n + 5Li --> 6Li + {\gamma} can make a significant contribution to the formation of 6Li at the BBN at least at temperatures T9 of the order of unity. Calculations of the total cross sections, astrophysical S-factor, and reaction rates have been performed for 3He(2H,{\gamma})5Li radiative capture within the modified potential cluster model with forbidden states, which follow from the classification of the orbital cluster states according to Young diagrams. Numerical data and corresponding parametrizations cover the energy range up to 5 MeV and temperature range T9<10. An updated compilation of detailed data for the reaction 3He(2H,{\gamma})5Li are presented.Comment: 33p., 7 tabl., 11 fi