RADIATIVE nB CAPTURE AT ASTROPHYSICAL ENERGIES

During the last half-century the microscopic model that goes by the name of the resonance group method (RGM, see, for example, [1, 2]) has become a very successful direction of development for nuclear physics, as can also be said for models associated with it, such as the generator coordinate method (GCM, see, in particular, [3]) or the algebraic version of the RGM [4]. However, to this day the possibilities of simple potential two-cluster models (PCMs) have not been fully investigated in the cases in which they employ the concept of forbidden states (FSs) [5] and directly allow for resonance behavior of the elastic scattering phases of the interacting particles at low energies [6, 7] – such a variant of the model can be called the modified PCM (MPCM). Far from always are comparatively complicated RGM calculations needed to explain the available experimental facts. To consider many problems it is sufficient to use the comparatively simple MPCM taking into account, as it does, the classification of orbital states according to the Young schemes, which leads to a representation of the FSs, and also the resonance behavior of the elastic scattering phases. Such an approach, as was shown earlier by the author [6, 7], makes it possible in many cases to obtain entirely adequate results in a description of many experimental data for total cross sections of thermonuclear processes of radiative capture type. For example, in [8] the possibility of describing the Coulomb form-factors of lithium nuclei on the basis of the potential cluster model [9, 10] was demonstrated. Such a model takes into account FSs [10–13] in the intercluster potentials, which were used already in [14]. Later, in [15] the possibility of a valid reproduction of practically all the characteristics of the Li nucleus was demonstrated, including its quadrupole moment, in a potential cluster model with tensor forces [11]. And finally, [9, 10, 16–21] demonstrated the possibility of describing astrophysical S-factors or total cross sections of almost thirty radiative capture processes at thermal and astrophysical energies. All these calculations were based on the modified variant of PCM described in [6, 7, 20]. Therefore, continuing the examination of capture processes presented in [6, 7], let us consider within the framework of the MPCM with FSs the reaction nB → γB at thermal and astrophysical energies, which plays a definite role in reactions of solar nucleosynthesis [22]. In the given case the potentials of the intercluster interactions for the scattering processes are constructed on the basis of a description of the structure of the spectra of the resonance states of the nB system. For the bound states (BSs) or ground states (GSs) of nuclei formed as a result of a capture