The breakup coupling effects on the rainbow scattering of ⁶Li at 35 AMeV

Highlights: • The rainbow scattering of loosely bound ⁶Li is analyzed systematically. • The dependence of the rainbow characteristic on the target mass is revealed. • The breakup coupling effects boost the nuclear rainbow in elastic scattering. • The stronger breakup coupling can lead to a stronger refraction. - Abstract: To investigate the breakup coupling effects on the formation of the nuclear rainbow, the existing experimental data of the refractive elastic scattering of ⁶Li on ¹²C, ⁴⁰Ca, ⁵⁸Ni and ⁹⁰Zr targets at 35 AMeV are analyzed. The continuum discretized coupled-channel (CDCC) method is adopted to calculate the elastic scattering angular distributions including the coupling effects from the breakup of ⁶Li into α and d. The one-channel (1-ch) calculations that switch off the breakup coupling are also performed for comparison. In the calculated angular distributions given by both approaches, the first Airy (A1) minimum shows a trend of moving to larger angles as the target mass increases. Comparing the calculated results through two approaches, one can find that the breakup coupling shifts the A1 minima to larger angles. This shows that the breakup coupling can boost the nuclear rainbow, although it also damps the elastic scattering cross sections. We also find that the stronger the breakup coupling is, the larger the A1 shift becomes.