Vol 82, No 1 (2019)

The scattering of slow particles with nonzero orbital angular momentum in the field of a finite potential is considered. The respective scattering problem is solved in the Pais approximation. The inverse problem is solved for the Pöschl-Teller equation, and a general scheme for Pais resonances and a procedure for calculating scattering cross sections for resonance particles are formulated.

The width of the neutral kaon with respect to its decay to a positively charged kaon, an electron, and an antineutrino is calculated. The branching ratios for the decay of K_L and K_S mesons to \({K^ + }{e^ - }{\bar \nu _e}\) are found to be about 4 × 10⁻⁹ and 10⁻¹¹ respectively. The calculations presented in this article are also valid for neutral antikaons decaying to a negatively charged kaon, a positron, and a neutrino.

The possibility of employing the isotope ^96gTc as a gamma-ray emitter in medical diagnostics is examined. Corresponding calculations by the TALYS-1.9 revealed that an irradiation of a ⁹⁶Mo target with protons of energy E =12 → 6 MeV at a current of 100 μA for six (eight) hours makes it possible to produce 20 (26) GBq of the isotope ^96gTc. In detecting gamma rays of energy in the range between 770 and 850 keV, the intensity of gamma rays from ^96gTc is close to their intensity for ^99mTc obtained in the reaction ¹⁰⁰Mo(p, n), so that one can use^96gTc as an alternative gamma-ray emitter.

The problem of reliability of the cross section data obtained for partial photoneutron reactions on ^76,78,80,82Se nuclei in beams of quasimonoenergetic annihilation photons by means of neutron multiplicity sorting is discussed by employing objective physical criteria. It is shown that, because of substantial systematic uncertainties, experimental data on the (γ, 1n) and (γ, 2n) cross sections are unreliable. New data satisfying the reliability criteria are obtained for the partial photoneutron reaction cross sections for ^76,78,82Se nuclei by an experimental—theoretical method for evaluating such cross sections and are compared with experimental data and with data evaluated earlier for the isotope ⁸⁰Se. The evaluated integrated cross sections for the total photoneutron reactions on ^76,78,80,82Se nuclei are compared with the predictions of the Thomas-Reiche-Kuhn classical dipole sum rule.

An experiment devoted to studying deuteron breakup induced by 778 MeV protons was performed with the aid of a deuterium bubble chamber. Experimental spectra are compared with results of calculations based on multiple-scattering theory that takes into account pole diagrams, elastic rescattering, and final-state interaction. The calculations in question describe a global behavior of the spectra, even though the theory itself was put forth for energies in the region around a few hundred GeV/c.

The influence of the partial-wave states with nonzero orbital moment of the nucleon pair on the binding energy of the triton T(nnp) in the relativistic case is considered. The relativistic generalization of the Faddeev equation in the Bethe-Salpeter formalism is applied. Two-nucleon t matrix is obtained from the Bethe-Salpeter equation with separable kernel of nucleon-nucleon interaction of the rank one. The kernel form factors are the relativistic type of the Yamaguchi functions. The following two-nucleon partial-wave states are considered: ¹S₀, ³S₁, ³D₁, ³P₀, ¹P₁, ³P₁. The system of the integral equations are solved by using the iteration method. The binding energy of the triton and three-nucleon amplitudes are found. The contribution of the P and D states to the binding energy of triton is given.

The probabilities for L-shell ionization following the alpha decay of ₁₁₇²⁹⁴Ts, ₁₁₃²⁸⁶Nh, ₁₀₉²⁷⁸Mt, and ₁₀₅²⁷⁰Db superheavy nuclei from the decay chain of tennessine, which was synthesized at the Joint Institute for Nuclear Research (JINR Dubna), and the alpha decay of the isotope ₈₄²¹⁰Po are calculated and analyzed. The respective calculations rely on a quantum-mechanical model that takes into account alpha-particle tunneling through the Coulomb barrier of an atom. The relativistic electron wave functions obtained by the Dirac-Fock method were employed. The probabilities for L-shell ionization that were calculated here for the isotope ₈₄²¹⁰Po are in better agreement with experimental data than the results of earlier calculations. In contrast to what we have for K-shell ionization, where monopole transitions make a dominant contribution to the ionization probability, a significant contribution to the probability for L-shell ionization also comes from dipole and quadrupole transitions. The results of the present study will be of use in interpreting superheavy-element spectra obtained by methods of combined alpha, gamma, and electron-conversion spectroscopy.