Two-proton radioactivity with 2p halo in light mass nuclei A = 18–34

Abstract

Two-proton radioactivity with 2p halo is reported theoretically in light mass nuclei A = 18-34. We predict 19 Mg, 22 Si, 26 S, 30 Ar and 34 Ca as promising candidates of ground state 2p-radioactivity with S 2p < 0 and S p > 0. Observation of extended tail of spatial charge density distribution, larger charge radius and study of proton single particle states, Fermi energy and the wave functions indicate 2p halo like structure which supports direct 2p emission. The Coulomb and centrifugal barriers in experimentally identified 2p unbound 22 Si show a quasi-bound state that ensures enough life time for such experimental probes. Our predictions are in good accord with experimental and other theoretical data available so far.

Magicity in the nuclei with N = 32 & 34

“…1 and 2, in which we have plotted potential energy surfaces for N=32 and 34 isotones, respectively, to examine the shapes in ground state as a function of quadrupole deformation β. Here, we have plotted both RMF [24,25] calculations using DD-ME2 [21] and NL3* [22] force parameter and it is noteworthy that both parameters are in good agreement and show reasonably the similar kind of shapes and ground state deformations. In both Figs.…”

Collapse of N$=$28 magicity in exotic $^{40}$Mg -- Probe of deformed halo and 2n-radioactivity at Mg neutron drip-line

“…Table I shows the extremely weak binding in 40 Mg with a small value of positive separation energy, whereas in the case of 42,44 Mg, S 2n < 0 and S n > 0 by most of the theories, which means the emission of two valence neutrons or dineutron is allowed but the sequential emission of one neutron is energetically forbidden indicating 2nradioactivity. A similar process of two proton-radioactivity which occurs when S p > 0 and S 2p < 0, was studied in our recent work [37] where the existence of 2p-halos in 2pemitters and the correlation between the 2p-halo and 2p-emission was shown. However, being close to N=Z line, the proton drip-line is experimentally easily accessible than the neutron drip-line which is why the 2n-emission is a less explored phenomena and reliable theoretical models are desirable.…”

“…We use relativistic mean-field approach (RMF) [29][30][31][32][33][34][35][36][37][38] for the present study where the various parameterizations/variants of the RMF models have been used for the calculations. The first variant of RMF comprises of the following model Lagrangian density with nonlinear terms for the σ and ω mesons [36,[39][40][41];…”

Structural properties and α-decay chains of transfermium nuclei (101≤Z≤110)

“…The calculations in the relativistic mean-field approach [17,[54][55][56][57][58] have been carried out using the model Lagrangian density with nonlinear terms both for the σ and ω mesons along with NL3* parametrization [59]. The corresponding Dirac equations for nucleons and Klein-Gordon equations for mesons obtained with the mean-field approximation are solved by the expansion method on the widely used axially deformed Harmonic-Oscillator basis [60,61].…”