Cluster decay half-lives of Ba112-122 isotopes from the ground state and intrinsic excited state using the relativistic mean-field formalism within the preformed-cluster-decay model

• Main Authors: Majekodunmi, Joshua T., Bhuyan, Mrutunjaya, Jain, D., Anwar, K., Abdullah, N., Kumar, Raj
• Format: Article
• Published: American Physical Society 2022
• Subjects: QC Physics
• Online Access: http://eprints.um.edu.my/42267/

Background: The cluster radioactivity from the neutron-deficient trans-tin region of the nuclear landscape has given immediate attention in the nuclear structure studies. Recent prediction of the emitting clusters from the ground and intrinsic excited states of proton-rich Ba isotopes opens the direction to explore the corresponding decay characteristics. A theoretical probe is necessary for understanding the cluster decays of Ba isotopes. Purpose: In the present study, cluster-decay half-lives are calculated and their decay characteristics are investigated for even-even Ba112-122 isotopes in both ground and intrinsic excited states along the proton drip line. Method: The preformed-cluster-decay model (PCM) is employed for estimating the decay half-lives. The preformation probability (P-0) of the cluster decay from the parent nuclei is calculated by using the well-known phenomenological formula of Blendowske and Walliser Phys. Rev. Lett. 61, 1930 (1988)], supplemented with the newly proposed Q-value-based preformation factor for the cluster with mass A(c) > 28. The penetration probability is calculated from the interaction potential using the Wentzel-Kramers-Brillouin (WKB) approximation. The nucleon-nucleon (NN) potential and individual binding energy (BE) of the cluster and daughter nuclei are estimated from the microscopic relativistic mean-field formalism (RMF) and compared with those from experiments and the finite-range-droplet model for the estimation of the Q values of the cluster decays. The nonlinear RMF Lagrangian from which the effective relativistic R3Y NN potential is derived using the NL3* parameter set is employed for the calculation of the nuclear matter densities. The R3Y and well-known M3Y potential are employed to obtain the cluster-daughter interaction potential using the double-folding procedure along with their corresponding RMF densities. The total potential along with their respective cluster decay Q values are used as input in the PCM to obtain the half-lives (T-1/2) of Ba112-122 isotopes in their ground and intrinsic excited states. Results: The calculated half-lives (T-1/2) for relativistic R3Y NN potential and Q values are found to deviate slightly compared to the ones from the M3Y due to the difference in their barrier characteristics. We notice that at elongated neck configuration a minimum neck-length parameter Delta R = 1.0 fm is required for R3Y potential due to its repulsive nature, whereas the value is 0.5 fm is suitable for the M3Y case. However, the estimated decay half-lives for both the potentials are in reasonably good agreement with the experimental lower limit of 114Ba. In contrast with the ground-state decays, the inclusion of intrinsic excitation reduces the corresponding half-life values considerably but does not rule out the role of magicity. Conclusions: The sensitivity of the decay half-lives to Q values and neck-length parameter has also been demonstrated. The decay half-lives are predicted for various cluster decays from neutron-deficient Ba isotopes. Since none of the experimental half-lives for the examined clusters is precisely known yet, further studies with available observed half-lives will be needed to substantiate our findings.