PHYSICAL REVIEW C 99, 014614 (2019) N / Z dependence of decay channels in A = 80 compound nuclei Manpreet Kaur, 1 , * BirBikram Singh, 1 , † Sarbjeet Kaur, 1 and Raj K. Gupta 2 1 Department of Physics, Sri Guru Granth Sahib World University, Fatehgarh Sahib 140406, India 2 Department of Physics, Panjab University, Chandigarh 160014, India (Received 26 July 2018; published 16 January 2019) A comparative decay analysis of 80 Zr ∗ , 80 Sr ∗ , and 80 Kr ∗ isobaric nuclear systems formed in 40 Ca + 40 Ca, 16 O + 64 Zn, and 32 S + 48 Ca reactions, respectively, has been conducted to investigate the N/Z dependence of different decay modes within a dynamical cluster-decay model based on the collective clusterization approach of quantum mechanical fragmentation theory. The comparative contributions of the emission of light particles (LPs), intermediate mass fragments (IMFs), and symmetric mass fragments (SMFs) in the total fusion cross- sections, σ fusion , have been calculated. The results show that LPs have a major contribution to σ fusion in the decay of all three compound nuclei (CN). The percentage contribution of LPs is larger for CN with higher N/Z ratio. The IMFs and SMFs cross-section are comparatively low in the total σ fusion but their emissions are in competition in the decay process. The results show that the shape of mass distribution evolves from symmetric to asymmetric with increasing N/Z ratio. The yield around SMFs is greater for the system having the lowest N/Z ratio. This may be attributed to higher P 0 for the symmetric exit channel, particularly at higher ℓ values. The calculated fusion cross-sections for all three CN are in good agreement with the experimental data. DOI: 10.1103/PhysRevC.99.014614 I. INTRODUCTION Heavy-ion reactions are an effective probe to study the nuclear structure and the characteristics of reaction dynamics. The hot and rotating compound nuclei (CN) formed in these reactions are de-excited from the different modes ranging from the evaporation of light particles (LPs) to fission and the intermediate mass fragments (IMFs) in between these two extremes. The study of fragment production is significant due to an increased interest in the production of “exotic” nuclei via the decay of excited CN [1–3]. The formation and decay of a CN into different exit channels is significantly influenced by various degrees of freedom such as beam energy, mass of the projectile and target combination, angular momentum, projectile and target neutron-to-proton (N/Z) ratios, mass asymmetry of the projectile and target combination, etc. The entrance channel mass asymmetry (η) plays a crucial role in the determination of CN formation probability for the synthesis of superheavy elements. Studies of the heavy mass region show that η and the shell structure of the colliding part- ners leading to the same CN strongly affect the competition between fusion and quasifission. It has been observed that, for different mass asymmetric reactions leading to the same CN, there is an increased compound nucleus fusion probability in a mass asymmetric reaction compared to that in a symmetric mass reaction [4,5]. The different mass asymmetric reactions leading to CN with the same Z show that the shape of the mass distribution strongly depends upon the mass asymmetry * Current affiliation: Institute of Physics, Bhubaneswar 751005, India; manpreetphys@gmail.com † birbikramsingh@sggswu.edu.in [6]. Also, the study of an incomplete fusion component is reported to be influenced by mass asymmetry, which rises with increasing η [7]. Another factor that affects the reaction dynamics and the fragment production in the exit channel is the N/Z ratio of CN. Several studies have shown that the fusion process is influenced considerably by the N/Z ratios of colliding nuclei [2,8]. The study of 78,82 Kr + 40 Ca reactions shows that sym- metric splitting yields are about 30% smaller for the neutron- rich system as compared to those for the neutron-deficient system [2]. The staggering in fragment cross-sections σ A , superimposed on mass distribution, depends on the size of the emitter nuclei as well as on the N/Z ratios of the emitter nuclei. The staggering in σ A may be due to the persistence of structure effects in fragment production mechanism. Besides, the neutron contents of emitter nuclei are apparent from the values of the IMFs cross-sections [9]. This raises the question about the N/Z dependence of different decay modes and channels, which is relatively unknown. On the theoretical front, several approaches, such as the Hauser-Feshbach approach, the transition-state model, and the dinuclear system model [10–12], have been developed to understand the various decay modes. These models are based on distinct assumptions and involve nuclear ingredients like fission barrier and level density to study the thermal and col- lective properties, which influence the competition between different decay paths. The neutron-proton compositions of nu- clei significantly affect these quantities [13]. Moreover, some studies near barrier have shown that the fusion mechanism is affected by the internal structures and N/Z contents of the colliding nuclei [8]. Therefore, it is important to explore the decay modes of nuclei at high angular momentum and having different N/Z ratios. Some studies have explored the role 2469-9985/2019/99(1)/014614(7) 014614-1 ©2019 American Physical Society