Theory of deuteron stripping: From surface integrals to a generalizedR-matrix approach

Abstract

There are two main reasons for absence of the practical theory of stripping to resonance states which could be used by experimental groups: numerical problem of the convergence of the DWBA matrix element when the full transition operator is included and it is unclear what spectroscopic information can be extracted from the analysis of transfer reactions populating the resonance states. The purpose of this paper is to address both questions. The theory of the deuteron stripping is developed, which is based on the post continuum discretized coupled channels (CDCC) formalism going beyond of the DWBA and surface integral formulation of the reaction theory [A. S. Kadyrov et al., Ann. Phys. 324, 1516. First, the formalism is developed for the DWBA and then extended to the CDCC formalism, which is ultimate goal of this work. The CDCC wave function takes into account not only the initial elastic d + A channel but also its coupling to the deuteron breakup channel p + n + A missing in the DWBA. Stripping to both bound states and resonances are included. The convergence problem for stripping to resonance states is solved in the post CDCC formalism. The reaction amplitude is parametrized in terms of the reduced width amplitudes (ANCs), inverse level matrix, boundary condition and channel radius, that is the same parameters which are used in the conventional R-matrix method. For stripping to resonance states many-level, one and two-channel cases are considered. The theory provides a consistent tool to analyze both binary resonant reactions and deuteron stripping in terms of the same parameters.

Midterm Progress Report for TORUS Topical Collaboration in Nuclear Theory

“…We have carried out studies for bound as well as resonance final states, as both types are important for extracting information that can be used to constrain nuclear structure models. In an extension of this work, we have developed a new formalism that makes use of concepts known from the successful and popular R-matrix theory (Section 3.4 and Publication [21]). The new formalism paves the way for an alternative description of transfers to resonances, able to characterize the measured cross sections in terms of resonance energies and widths, and thus to connect to astrophysically relevant capture reactions and nuclear structure studies.…”

Measurement of the B10(p,α0)Be7 cross section from 5 keV to 1.5 MeV

“…It has been proved that the HOES cross section is essentially linked to the OES one by the penetration factor of the Coulomb barrier [47][48][49][50], calculated introducing the correct wave number and interaction radius for the p-10 B system. The THM cross section is then obtained through the relation:…”

Deuteron-induced nucleon transfer reactions within anab initioframework: First application top-shell nuclei

“…In this way the pairs and triplets of creation and annihilation operators in Eqs. (12) and (13) are implemented through bitwise operations, that allow to select efficiently the non-trivial density matrices for a given target state in input.…”