Searches for nuclear-stable multineutrons among products originating from the fission of ²³⁸U nuclei that is induced by 62-MeV alpha particles were performed by the activation method. The reaction involving the transfer of four neutrons and occurring on the isotope ⁸⁸Sr, ⁸⁸Sr( ^x n, (x − 4) n)⁹²Sr→⁹²Y, was used to identify nuclear-stable multineutrons. A line at the energy of E = 1384 keV was found in the measured gamma-ray spectra of irradiated samples. This line, together with the measured time dependence of the decrease in its activity, is indicative of the formation of the beta-active nucleus ⁹²Sr. This result was reproduced in repeated measurements. It suggests the possible existence of nuclear-stable multineutrons ( ^x n) for x ≥ 6. The differential cross section for the ^x n yield at an angle of 30° in the alpha-particle-induced fission of ²³⁸U was about 6 × 10⁻² mb/sr.

Light nuclear-stable multineutrons among products of the fission of ²³⁸U nuclei that is induced by 62-MeV alpha particles have been searched by the activation method with a ²⁷Al sample. These multineutrons have been detected by characteristic gamma rays emitted by the nuclei from the beta-decay chain ²⁸Mg → ²⁸Al → ²⁸Si. The ²⁸Mg parent nucleus can be formed in the ²⁷Al + ^x n → ²⁸Mg + p(x − 2) n process. The gamma-ray spectra of the irradiated sample exhibit lines of 1342- and 1779-keV photons accompanying the beta decay of the ²⁸Mg and ²⁸Al nuclei, respectively. The decrease in the activity corresponds within the measurement accuracy with the half-life T _1/2 ∼ 21 h of ²⁸Mg, which certainly indicates the detection of nuclear-stable multineutrons ^x n with x ≥ 6.

The availability of a comparatively complete data set for the elastic and inelastic scattering of a 45-MeV beam of ${}^{11}\mathrm{B}$ ions from a ${}^{14}\mathrm{C}$ target, together with an angular distribution for the ${}^{14}\mathrm{C}({}^{11}\mathrm{B},{}^{12}\mathrm{C}){}^{13}\mathrm{B}$ proton pickup reaction enables a determination of the $\langle {}^{14}\mathrm{C}\mid {}^{13}\mathrm{B}+p\rangle$ asymptotic normalization coefficient (ANC) using the coupled reaction channel (CRC) technique. The complete nature of the data set allows two-step contributions to the reaction mechanism to be controlled while a set of $\langle {}^{12}\mathrm{C}\mid {}^{11}\mathrm{B}+p\rangle$ overlaps obtained from a consistent analysis of ($d,{}^3\mathrm{He}$) and ($e,e^{\prime }p$) data fixes the projectile overlaps. We find that the level of completeness of the modeling of the reaction mechanism has a significant effect on the value obtained for the ANC, with a distorted wave Born approximation analysis yielding a significantly larger ANC than the full CRC calculation. The final result obtained, when compared with the theoretical value calculated within the source term approach, is in accord with trends for proton removal from similar $p$-shell nuclei.

The angular distributions of the elastic and inelastic scattering of α-particles on ¹⁰B nuclei were measured at an energy of 29 MeV (with excitation of the 0.718 MeV (1⁺) state). The data obtained by us, together with the angular distributions of the elastic scattering measured earlier in a wide range of energies from 24 to 90 MeV, were described using an optical model, the coupled-channel method, and parameterized phase analysis. The optimal parameters of optical potentials were found, and a good description of the experimental data in the specified energy range of α-particles was achieved. By taking into account the contribution of the elastic transfer mechanism of the ⁶Li cluster, it was possible to correctly reproduce the rise of the cross section at the backward angles in the elastic channel. The value of the quadrupole deformation parameter was extracted from the analysis of inelastic scattering using the coupled-channel method. The geometric parameters of the interaction potentials were determined using parameterized phase analysis. The radii of the ¹⁰B nuclei in the high-energy region (30 MeV and above) obtained by PPA are in good agreement with the radii calculated in the framework of the optical model.

The elastic and inelastic scattering of deuterons on ¹⁰B nuclei and the ¹⁰B(d, t)⁹B reaction were studied at a deuteron energy of 14.5 MeV. In inelastic scattering, differential cross-sections for transitions to ¹⁰B states at excitation energies, E_x, of 0.718 MeV (1⁺), 2.154 MeV (1⁺), and 3.59 MeV (2⁺) were measured. The cross-sections of the (d, t) reaction were measured for the ground (3/2⁻) and excited states of the ⁹B nucleus at E_x = 2.361 MeV (5/2⁻) and 2.79 MeV (5/2⁺). An analysis of the corresponding angular distributions was carried out using the coupled channel method. As a result of the calculations, the values of the quadrupole deformation parameters (β₂ ≈ 0.7 ± 0.1) for various transitions in the ¹⁰B nucleus in inelastic scattering were extracted. From the analysis of the (d, t) reaction, the values of spectroscopic amplitudes (SA = 0.67 and SA = 0.94) for transitions to the states of the ⁹B nucleus were extracted. The results obtained here, taking into account possible measurement errors, are in good agreement with the previously obtained data and the theoretical predictions.