Investigating the influence of input angular momentum on independence hypothesis in heavy-ion induced fusion reactions

The experimental verification of compound nucleus theory has successfully been performed for light ion induced reactions using proton and α-particle beams on different targets. However, such studies using the heavy ion beams are scarce due to the complex nature of heavy ion interaction process. The present work is an attempt to validate the Bohr's independent hypothesis using heavy ion beam of ¹⁸O beam on ¹⁵⁹Tb targets and ¹²C on ¹⁶⁵Ho targets, forming the same compound nucleus ¹⁷⁷Ta. A channel wise analysis of cross section data for evaporation residues produced in ¹⁸O+¹⁵⁹Tb and ¹²C+¹⁶⁵Ho systems has been performed within the framework of statistical model code PACE4 and found to reasonably agree with the experimental data. Further, a comparison of reaction cross section data for the same evaporation residues produced in the two different systems has been found to follow Bohr's compound nucleus hypothesis at relatively higher excitation energies. However, at relatively lower excitation energies, a significant deviation in the measured cross section data of the same residues in the above mentioned systems have been observed and is attributed to the discrepancies in angular momentum values. Such discrepancies are well explained on the basis of input angular momentum involved in the reactions.