Structure of 8B from elastic and inelastic 7Be + p scattering
J. P. Mitchell, G. V. Rogachev, E. D. Johnson, L. Baby, K. W. Kemper, A. M. Moro, P. Peplowski, A. Volya, and I. Wiedenhöver
Accepted
\begin{description} \item[Background] Detailed experimental knowledge of the level structure of light weakly bound nuclei is necessary to guide the development of new theoretical approaches that combine nuclear structure with reaction dynamics. \item[Purpose] The resonant structure of $^8$B is studied in this work. \item[Method] Excitation functions for elastic and inelastic $^7$Be+p scattering were measured using a $^7$Be rare isotope beam. Excitation energies ranging between 1.6 and 3.4 MeV were investigated. An R-matrix analysis of the excitation functions was performed. \item[Results] New low-lying resonances at 1.9, 2.54, and 3.3 MeV in $^8$B are reported with spin-parity assignment 0$^+$, 2$^+$, and 1$^{+}$, respectively. Comparison to the Time Dependent Continuum Shell (TDCSM) model and {\it ab initio} no-core shell model/resonating-group method (NCSM/RGM) calculations is performed. This work is a more detailed analysis of the data first published as a Rapid Communication. [J.P. Mitchell, et al, Phys. Rev. C 82, 011601(R) (2010)] \item[Conclusions] Identification of the 0$^+$, 2$^+$, 1$^{+}$ states that were predicted by some models at relatively low energy but never observed experimentally is an important step toward understanding the structure of $^8$B. Their identification was aided by having both elastic and inelastic scattering data. Direct comparison of the cross sections and phase shifts predicted by the TDCSM and {\it ab initio} No Core Shell Model coupled with the resonating group method is of particular interest and provides a good test for these theoretical approaches. \end{description}