Global description of the ${}^7\mathrm{Li}+p$ reaction at 5.44 MeV/u in a continuum-discretized coupled-channels approach

The complete set of open channels for the ${}^7\mathrm{Li}+p$ system, namely elastic scattering, inelastic scattering, breakup, the ${}^7\mathrm{Li}+p\to {}^7\mathrm{Be}+n$ charge exchange reaction, and the ${}^7\mathrm{Li}+p\to {}^4\mathrm{He}+{}^4\mathrm{He}$ reaction, was measured in the same experiment in inverse kinematics at an energy of 5.44 MeV/u. Data were also obtained for the charge exchange reaction at energies of 5.0 and 3.57 MeV/u. The elastic and inelastic scattering and breakup data were reported previously and are reviewed here and, together with the new data for the other two reactions, are discussed coherently within the same continuum-discretized coupled-channels model framework.

Figure 1

The present experimental angular distributions for the ${}^7\mathrm{Li}+p\to {}^7\mathrm{Be}+n$ charge exchange reaction to the ${}^7\mathrm{Be}$ ground state at (a) 5.44 MeV/u (38.1 MeV), (b) 5.0 MeV/u (35 MeV), and (c) 3.57 MeV/u (25 MeV) compared with existing data [4, 5]. The present data are denoted by red stars while those from Ref. [4] are denoted by blue squares and refer to energies of (a) 5.5 MeV/u, (b) 5.0 MeV/u, and (c) 4.25 MeV/u and denoted by green circles in panel (a) and refer to an energy of 5.0 MeV/u. Data from Ref. [5] are denoted by cyan triangles in panel (c) and refer to an energy of 3.8 MeV/u. The uncertainties in the present data do not exceed 11% and are smaller than the size of the points.

Figure 2

The present experimental angular distributions for the ${}^7\mathrm{Li}+p\to {{}^7\mathrm{Be}}^{*}+n$ charge exchange reaction to the first excited state of ${}^7\mathrm{Be}$ (red stars) at (a) 5.44 MeV/u (38.1 MeV) and (b) 3.57 MeV/u (25 MeV) compared with existing data [4] (blue squares) at (a) 5.5 MeV/u and (b) 4.2 MeV/u. The uncertainties in the present data do not exceed 15% and are smaller than the size of the points.

Figure 3

Two-dimensional $\mathrm{\Delta }E-E$ energy plot obtained for the ${}^7\mathrm{Li}+p\to {}^4\mathrm{He}+{}^4\mathrm{He}$ reaction at 5.44 MeV/u (38.1 MeV) by one strip of the GLORIA DSSSD module ($\sim {40}^{\circ }$).

Figure 4

Angular distribution for the ${}^7\mathrm{Li}+p\to {}^4\mathrm{He}+{}^4\mathrm{He}$ reaction at 5.44 MeV/u. The present data are denoted by the solid circles. The solid curve denotes the Legendre polynomial fit to the angular distribution.

Figure 5

Elastic scattering angular distributions for ${}^7\mathrm{Li}+p$ at (a) 2.29 MeV/u, (b) 3.57/u, (c) 5.0 MeV/u, and (d) 5.44 MeV/u. fresco calculations are also shown as the dot-dashed blue lines, one-channel for panel (a) and full CDCC for panels (b), (c), and (d). Details of the measurement and calculations are also reported in Ref. [1].

Figure 6

The elastic scattering angular distribution at 5.44 MeV/u (red stars) compared with previous data at 6.1 MeV/u (green circles) [6] and the following fresco calculations: one-channel (dashed red line), two-channel (dotted blue line), full CDCC (solid black line), and finally a CDCC calculation omitting coupling to the resonance (solid cyan line). It is obvious that at backward angles the effect of coupling to the resonance is very strong. This figure is based on Fig. 4 of Ref. [1] and Fig. 1 of Ref. [3], including additional calculations via decoupling of resonance and direct breakup.

Figure 7

Comparison of existing data for the ${}^7\mathrm{Li}+p$ system with the results of CDCC calculations fitting measured elastic scattering. The dotted black and dashed red curves denote the ${}^7\mathrm{Li}$($p,\alpha$) and ${}^7\mathrm{Li}$($p,p^{\prime }$) inelastic scattering excitation functions of Ref. [6], respectively. The small solid and open blue circles denote the total (ground plus first excited state of ${}^7\mathrm{Be}$) charge exchange excitation functions of Refs. [4] and [14], respectively, validated by the present data. The solid green curve denotes the sum of the interpolated charge exchange and ${}^7\mathrm{Li}$($p,\alpha$) excitation functions. The large solid cyan circles denote the calculated total breakup cross sections, the large solid red diamonds the calculated ${}^7\mathrm{Li}$($p,p^{\prime }$) inelastic scattering cross sections, the large open green squares the calculated total absorption cross sections, and the large solid black squares the calculated total reaction cross sections. The datum denoted with a red star (the upper star) refers to our breakup measurement reported in Ref. [3] and obtained at an experiment simultaneously with the data reported here. Also the datum denoted with the magenta star (the lower star) refers to the present measurement of the reaction ${}^7\mathrm{Li}+p\to {}^4\mathrm{He}+{}^4\mathrm{He}$.