Nucleus-Nucleus Scattering in the High-Energy Approximation and the Optical Folding PotentialFor the nucleus-nucleus scattering, the complex potential is obtained which corresponds to the eikonal phase of an optical limit of the Glauber-Sitenko high-energy approximation. The potential does not include free parameters, its real and imaginary parts depend on energy and are determined by the reported data on the nuclear density distributions and nucleon-nucleon scattering amplitude. Alternatively, for the real part, the folding potential can be utilized which includes the effective NN -forces and the exchange term, as well. As a result, the microscopic optical potential is constructed where contributions of the calculated real and imaginary parts are formed by fitting the two respective factors. An efficient of the approach is confirmed by agreements of calculations with the experimental data on elastic scattering cross-sections.The investigation has been performed at the Bogoliubov Laboratory of Theoretical Physics, JINR. ‚´ ¸ÉµÖÐ¥°· ¡µÉ¥ ³Ò ¶·¥¤² £ ¥³ ³¨±·µ¸±µ ¶¨Î¥¸±¨° ¶µ¤Ìµ¤, £¤¥ ± ± ¢¥Ð¥¸É¢¥´´ Ö, É ±¨³´¨³ Ö Î ¸ÉÓ ¶µÉ¥´Í¨ ² ¢ÒΨ¸²ÖÕɸִ ¡ §¥ ³¨±·µ-±µ ¶¨Î¥¸±¨Ì ³µ¤¥²¥°. ' Ôɵ°Í¥²ÓÕ¨¸ ¶µ²Ó §Ê¥É¸Ö µ ¶É¨Î¥¸±¨° ¶µÉ¥´Í¨ ², ±µ-ɵ·Ò°³µ¦´µ´ °É¨± ± ɵδµ¥¸µµÉ¢¥É¸É¢¨¥ µ ¶É¨Î¥¸±µ³Ê ¶·¥¤¥²Ê ³¨±·µ¸±µ- ¶¨Î¥¸±µ°³µ¤¥²¨· ¸¸¥Ö´¨Ö ¢ ¢Ò¸µ±µÔ´¥·£¥É¨Î¥¸±µ³ ¶·¨¡²¨¦¥´¨¨(‚), ¶·¥¤²µ¦¥´´µ°¢´ Î ²¥ ƒ² Ê¡¥·µ³¨'¨É¥´±µ ¤²Ö ¤·µ´-Ö¤¥·´µ£µ · ¸¸¥Ö´¨Ö [10, 11], ¶µ §¤´¥¥ µ¡µ¡Ð¥´´µ°´ ¸²ÊÎ °· ¸¸¥Ö´¨Ö Ö¤¥· [12,13]. ‚ ·Ö¤¥ ²ÊÎ ¥¢ ¤²Ö · ¸Î¥É ¢¥Ð¥¸É¢¥´´µ°Î ¸É¨ ¶µÉ¥´Í¨ ² ³Ò¨¸ ¶µ²Ó §Ê¥³ É ±¦¥ OE""¸ÊΥɵ³ µ¡³¥´ ´Ê±²µ´ ³¨. ÉµÉ ³ É¥·¨ ²¨ §²µ¦¥´¢ · §¤. 1¨2. ‚ · §¤. 3 ¶·¨¢µ¤ÖÉ¸Ö · ¸Î¥ÉÒ É ±¨Ì ¶µÉ¥´Í¨ ²µ¢, ¶·¥¤² £ ¥É¸Ö ³µ¤¥²Ó ¶µ¤£µ´±¨, ±µ£¤ ¢ ·Ó¨·ÊÕÉ¸Ö ¤¢ ´µ·³¨·ÊÕÐ¨Ì ³´µ¦¨É¥²Ö, µ ¶·¥¤¥²ÖÕÐ¨Ì ¢±² ¤ ¢¥Ð¥-É¢¥´´µ°¨³´¨³µ°Î ¸É¨ ¶µÉ¥´Í¨ ² , ¤ ´µ¸· ¢´¥´¨¥¸Ô±¸ ¶¥·¨³¥´É ²Ó´Ò³¥ Î¥´¨Ö³¨Ê ¶·Ê£µ£µ · ¸¸¥Ö´¨Ö.

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Abstract. Calculations of microscopic optical potentials (OP's) (their real and imaginary parts) are performed to analyze the 6 He+p elastic scattering data at a few tens of MeV/nucleon (MeV/N). The OP's and the cross sections are calculated using three model densities of 6 He. Effects of the regularization of the NN forces and their dependence on nuclear density are investigated. Also, the role of the spin-orbit terms and of the non-linearity in the calculations of the OP's, as well as effects of their renormalization are studied. The sensitivity of the cross sections to the nuclear densities was tested and one of them that gives a better agreement with the data was chosen.

Background: Aspects of the nuclear structure of light α-conjugate nuclei have long been associated with nuclear clustering based on α particles and heavier α-conjugate systems such as 12 C and 16 O. Such structures are associated with strong deformation corresponding to superdeformed or even hyperdeformed bands. Superdeformed bands have been identified in 40 Ca and neighboring nuclei and find good description within shell model, mean-field, and α-cluster models. The utility of the α-cluster description may be probed further by extending such studies to more challenging cases comprising lighter α-conjugate nuclei such as 24 Mg, 28 Si, and 32 S. Purpose: The purpose of this study is to look for the number and energy of isoscalar 0 + states in 28 Si. These states are the potential bandheads for superdeformed bands in 28 Si corresponding to the exotic structures of 28 Si. Of particular interest is locating the 0 + bandhead of the previously identified superdeformed band in 28 Si. Methods: α-particle inelastic scattering from a nat Si target at very forward angles including 0• has been performed at the iThemba Laboratory for Accelerator-Based Sciences in South Africa. Scattered particles corresponding to the excitation energy region of 6 to 14 MeV were momentum-analysed in the K600 magnetic spectrometer and detected at the focal plane using two multiwire drift chambers and two plastic scintillators. Results: Several 0 + states have been identified above 9 MeV in 28 Si. A newly identified 9.71 MeV 0 + state is a strong candidate for the bandhead of the previously discussed superdeformed band. The multichannel dynamical symmetry of the semimicroscopic algebraic model predicts the spectrum of the excited 0 + states. The theoretical prediction is in good agreement with the experimental finding, supporting the assignment of the 9.71-MeV state as the bandhead of a superdeformed band. Conclusion: Excited isoscalar 0+ states in 28 Si have been identified. The number of states observed in the present experiment shows good agreement with the prediction of the multichannel dynamical symmetry.

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