Refractive effects and Airy structure in inelasticO16+C12rainbow scattering

Abstract

Inelastic16 O + 12 C rainbow scattering to the 2 + (4.44 MeV) state of 12 C was measured at the incident energies, EL = 170, 181, 200, 260 and 281 MeV. A systematic analysis of the experimental angular distributions was performed using the coupled channels method with an extended double folding potential derived from realistic wave functions for 12 C and 16 O calculated with a microscopic α cluster model and a finite-range density-dependent nucleon-nucleon force. The coupled channels analysis of the measured inelastic scattering data shows consistently some Airy-like structure in the inelastic scattering cross sections for the first 2 + state of 12 C, which is somewhat obscured and still not clearly visible in the measured data. The Airy minimum was identified from the analysis and the systematic energy evolution of the Airy structure was studied. The Airy minimum in inelastic scattering is found to be shifted backward compared with that in elastic scattering.

Existence of inelastic supernumerary nuclear rainbow in O16+C12 scattering

“…For the most typical 16 [13-17, 27, 36] and we have studied the specific mechanism of nuclear rainbows for this system such as the existence of a dynamically generated secondary bow [37], a ripple structure [38] and a dynamically refracted primary rainbow [39]. The present authors were recently able to systematically verify the existence of the Airy minimum, A1, of the primary rainbow for newly measured 16 O+ 12 C inelastic scattering in the energy range E L =170-281 MeV [28]. A systematic evolution of the angular position of the Airy minimum A1 with the inverse of the center-of-mass energy was revealed.…”

“…The dashed line, solid line and the dotted line represent the coupled channels calculation with W = 16 (Table I) for elastic and inelastic scattering to the 2 + state of 12 C at the higher energies E L =260 and 281 MeV determined in Ref. [28] are also included. The Airy minimum A1 for inelastic scattering is slightly shifted backward compared with that for elastic scattering.…”

“…The nuclear rainbow in inelastic scattering has been observed and studied extensively in Refs. [7,[22][23][24][25][26][27][28][29].…”

Evidence for a dynamically refracted primary bow in weakly boundBe9rainbow scattering fromO16

“…An imaginary potential with a Woods-Saxon volume-type (nondeformed) form factor is introduced phenomenologically to take into account the effect of absorption due to other channels. A complex coupling, which is often used but has no rigorous theoretical justification especially for a composite projectile [33], is not introduced because without it the present EDF model successfully reproduced many rainbow scattering data systematically over a wide range of incident energies [6,7,22,23,[34][35][36][37][38][39]. [21] in the rainbow energy region.…”

“…Hitherto we have shown the results calculated by using the DDM3Y force with a density-dependence of Kobos type [29], which has been successful for many calculations of nuclear rainbow scattering [6,7,22,23,[34][35][36][37][38][39]. The χ 2 values at 74.25 MeV (157.7 MeV) for the single channel ( Fig.…”