Microscopic description of ${}^7\mathrm{Li}$ in ${}^7\mathrm{Li}$ + ${}^{12}\mathrm{C}$ and ${}^7\mathrm{Li}$ + ${}^{28}\mathrm{Si}$ elastic scattering at high energies

We employ a microscopic continuum-discretized coupled-channels reaction framework (MCDCC) to study the elastic angular distribution of the ${}^7\mathrm{Li}=\alpha +t$ nucleus colliding with ${}^{12}\mathrm{C}$ and ${}^{28}\mathrm{Si}$ targets at $E_{\mathrm{Lab}}=350$ MeV. In this framework, the ${}^7\mathrm{Li}$ projectile is described in a microscopic cluster model and impinges on noncomposite targets. The diagonal and coupling potentials are constructed from nucleon-target interactions and ${}^7\mathrm{Li}$ microscopic wave functions. We obtain a fair description of the experimental data, in the whole angular range studied, when continuum channels are included. The inelastic and breakup angular distributions on the lightest target are also investigated. In addition, we compute ${}^7\mathrm{Li}+{}^{12}\mathrm{C}$ MCDCC elastic cross sections at energies much higher than the Coulomb barrier and we use them as reference calculations to test the validity of multichannel eikonal cross sections.

Figure 1

CDCC Elastic cross sections (divided by the Rutherford cross section) of a composite ${}^7\mathrm{Li}$ impinging on ${}^{12}\mathrm{C}$ and ${}^{28}\mathrm{Si}$ targets. The solid lines labeled G.S. correspond to the single-channel cross sections. The ones labeled B.S. include the $3/2^{-}$ and $1/2^{-}$ bound states only. The six dashed lines represent the calculations that consider, in addition to the bound states, the breakup channels up to a determined $J_{\mathrm{Pmax}}=1/2$–11/2. Each $J_{\mathrm{Pmax}}$ increases from the top to the bottom. The curves with $J_{\mathrm{Pmax}}=7/2$–11/2 are superimposed. The points are the experimental data from Ref. [38].

Figure 2

Convergence of the CDCC elastic scattering cross section with the cutoff excitation energy of the projectile $E_{\max }$. The solid, dashed, dashed-dotted, and dotted lines correspond to $E_{\max }=7$, 11, 15, and 19 MeV, respectively. The calculations include breakup channels up to $J_{\mathrm{Pmax}}=7/2$. The curve corresponding to $E_{\max }=15$ MeV is superimposed with the curve $E_{\max }=19$ MeV.

Figure 3

Nucleon-${}^{28}\mathrm{Si}$ elastic cross sections calculated using different optical potentials. The solid, dashed, and dotted lines correspond to the KD [37], WP [36], and MD [39] potentials, respectively.

Figure 4

Influence of the nucleon-target nuclear potential on the ${}^7\mathrm{Li}{+}^{28}\mathrm{Si}$ elastic scattering. The solid, dashed, and dotted lines are the calculations using the KD [37], WP [36], and MD [39] optical potentials, respectively.

Figure 5

CDCC ${}^7\mathrm{Li}{+}^{12}\mathrm{C}$ breakup (solid line), elastic (dashed line), and inelastic (dashed-dotted line) angular distributions.

Figure 6

${}^7\mathrm{Li}{+}^{12}\mathrm{C}$ eikonal-CDCC elastic cross section (divided by the Rutherford cross section). The solid line labeled G.S. corresponds to the single-channel cross sections. The one labeled B.S. includes the $3/2^{-}$ and $1/2^{-}$ bound states only. The six dashed lines represent the calculations that consider, in addition to the bound states, the breakup channels up to a determined $J_{\mathrm{Pmax}}=1/2$–11/2. Each $J_{\mathrm{Pmax}}$ increases from the top to the bottom. The curves with $J_{\mathrm{Pmax}}=7/2$–11/2 are superimposed. The points are the experimental data from Ref. [38].

Figure 7

Comparison between the CDCC (solid lines) and eikonal-CDCC (dashed lines) elastic cross sections at different incident energies. The red curves correspond to single-channel predictions. The green (black) curves are the calculations including in addition to the bound states the breakup channels up to $J_{\mathrm{Pmax}}=3/2$ ($J_{\mathrm{Pmax}}=7/2$).