PHYSICAL REVIEW C 105, 014609 (2022) Systematic study of fusion suppression for tightly bound projectiles at above-barrier energies M. Shariq Asnain , 1, * Mohd. Shuaib , 1 Ishfaq Majeed, 1 Manoj Kumar Sharma, 2 Vijay R. Sharma, 3 Abhishek Yadav, 4 Devendra P. Singh, 5 Pushpendra P. Singh, 6 Sushil Kumar, 7 R. Kumar, 7 B. P. Singh, 1 , † and R. Prasad 1 1 Accelerator Laboratory, Department of Physics, Aligarh Muslim University, Aligarh 202 002, Uttar Pradesh, India 2 Department of Physics, Shri Varshney College, Aligarh 202 001, Uttar Pradesh, India 3 Instituto de Fisica, Universidad Nacional Autonoma de Mexico, Mexico City 04510, Mexico 4 Department of Physics, Faculty of Natural Sciences, Jamia Millia Islamia, New Delhi 110025, India 5 Department of Physics, University of Petroleum and Energy Studies, Dehradun 248 007, Uttarakhand, India 6 Department of Physics, Indian Institute of Technology, Ropar 140 001, Punjab, India 7 Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067, India (Received 19 November 2021; accepted 20 December 2021; published 10 January 2022) The present work aims to explore the effects of projectile breakup on fusion cross section at energies near the Coulomb barrier to well above it. The complete fusion cross section for the strongly bound non-α-cluster projectile 14 N in interaction with a 181 Ta target was obtained by summing the experimentally measured channel- by-channel cross section data of evaporated residues. The obtained total fusion cross section was compared with the theoretical code CCFULL and the results were found to be consistent with each other. Further, the experimental fusion function data on 181 Ta target with 14 N projectile were deduced and compared with those obtained for other strongly bound projectiles, viz., 12,13 C, 16 O, and 19 F, in order to get some systematics in fusion reactions. The analysis of experimental fusion functions was performed within the framework of a benchmark curve called the universal fusion function (UFF). A suppression of about 5–25% with respect to UFF was observed for the presently studied systems at energies above the Coulomb barrier, indicating that the suppression is essentially due to the prompt breakup of the projectiles and is a strong function of breakup threshold of projectiles. The magnitude of such suppression was found to be lower for 14 N projectile as compared to other strongly bound projectiles. Moreover, an interesting exponential relation between the experimentally deduced suppression factor and the breakup threshold of the projectile was obtained. DOI: 10.1103/PhysRevC.105.014609 I. INTRODUCTION The study of heavy-ion (HI) induced fusion processes, in order to understand different mechanisms involved in these reactions, has been a topic of interest in nuclear physics. With varying projectile energies, the complex nature and behavior of projectile and target nuclei makes it possible to characterize the reaction mechanism and may help to study the possibility of producing superheavy elements (SHE) in the laboratory [1–5]. Recent studies on HI interactions indicate the presence of incomplete fusion (ICF) processes along with the complete fusion (CF) even at low energies ≈4–7 MeV/A [6–12]. In the case of CF, the target hugs the entire projectile with all the incoming partial waves of input angular momenta ℓ<ℓ crit , contributing to the formation of a highly excited composite system. In the case of ICF reactions, the projectile breaks up into fragment(s) and one of the fragment(s) fuses with the target nucleus, whereas the remnant continues to move in the beam direction without any interaction. In such cases, the fu- sion of the entire projectile with the target nucleus is hindered for angular momentum values ℓ>ℓ crit . Experimentally, the analysis of fusion processes in the case of HI reactions is * asnainshariq@gmail.com † bpsinghamu@gmail.com rather delicate due to the competition of other reaction mecha- nisms such as transfer, breakup, preequilibrium reactions, etc. Further, the breakup and the preequilibrium emission may become important [13] at relatively higher energies and has attracted a great deal of interest in recent years [14,15]. In the literature, investigations carried out for HI fusion reactions suggest that the effective potential V eff (r ), which is the sum of nuclear, Coulomb and centrifugal potential, is sensitive around the nuclear surface region and is given as V eff (r ,ℓ) = V nucl (r ) + V Coul (r ) + V cent (r ,ℓ), (1) where the terms V nucl (r ), V Coul (r ), and V cent (r ,ℓ) represents the attractive nuclear, repulsive Coulomb, and repulsive cen- trifugal potentials respectively. A typical variation of effective potential V eff (r ) with relative separation (r ) between projectile and target nucleus for different angular momentum (ℓ) values is shown in Fig. 1. As can be seen from this figure, there is an attractive pocket for lower values of ℓ, which is called the fusion pocket, where the complete fusion of projectile and target nucleus takes place. However, for higher values of ℓ, this pocket starts vanishing and fusion does not occur. Hence, in order to provide sustainable angular momentum for fusion to occur, the projectile may break up into fragments and lead to the ICF process. The presence of ICF reactions in HI collisions at these energies has inspired an interest to 2469-9985/2022/105(1)/014609(9) 014609-1 ©2022 American Physical Society