Seminar “Nuclear Theory”

Date and Time: Monday, 28 June 2021, at 3:30 PM

Venue: Online conference on Zoom, Bogoliubov Laboratory of Theoretical Physics

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Seminar topic: “Three-nucleon nuclei in the Bethe-Salpeter-Faddeev formalism”

Speaker: S. A. Yurev

Abstract:

Three—nucleon nuclei (³He and ³H) were considered in the framework of the relativistic covariant Bethe-Salpeter approach. The Bethe-Salpeter-Faddeev system of integral equations was solved by the iteration method. Various separable potentials of nucleon-nucleon interaction were used – Yamaguchi, Tabakin, Graz-II, Paris-1(2). The S, P and D states of the three-nucleon system were considered. The binding energy and amplitudes of nuclear states are found, and the contribution of states with nonzero orbital angular momenta (P and D) to the binding energy is estimated. The contribution of the P and D states was 1-2% compared to the S state, depending on the type of the NN interaction potential used. The form factors of three-nucleon nuclei are calculated for the momentum transfer square up to 50 fm^-2 using various models of nucleon factors – a dipole fit, a relativistic harmonic oscillator model, and a vector dominance model. When calculating the form factors, relativistic corrections are taken into account, such as the Lorentz transformations of the propagator arguments, a simple pole in the propagator, and the Lorentz transformations of the wave function arguments of the finite nucleus. The calculation results have shown a significant contribution of relativistic corrections. The calculations using multi-rank potentials reproduce the diffraction minimum observed in the experimental data while taking relativistic corrections into account improves the agreement with experimental data.

(based on PhD thesis)