Effect of the inelastic couplings on the scattering of alpha particles by 12C at low energies

We study the effects of the coupling to the first 2+12C excited state on the elastic scattering and capture reaction for the α + 12C system. The flux absorption from the elastic channel to the capture reaction is simulated by a tiny imaginary part included in the optical potential. Our analyses show that the effect of the coupling is quite significant even at energies below the threshold of the inelastic channel. We also study the behavior of the polarization potential as a function of the energy and angular momentum. (paper)