Magic Nuclei in Superheavy Valley

Abstract

An extensive theoretical search for the proton magic number in the superheavy valley beyond Z =82 and corresponding neutron magic number after N =126 is carried out. For this we scanned a wide range of elements Z = 112 − 130 and their isotopes. The well established non-relativistic Skryme-Hartree-Fock and Relativistic Mean Field formalisms with various force parameters are used. Based on the calculated systematics of pairing gap, two neutron separation energy and the shell correction energy for these nuclei, we find Z =120 as the next proton magic and N=172, 182/184, 208 and 258 the subsequent neutron magic numbers. Keywords:After the discovery of artificial transmutation of elements by Sir Ernest Rutherford in 1919 [1], the search for new elements is an important issue in nuclear science. The existence of elements beyond the last heaviest naturally occurring 238 U, i.e., the discovery of Neptunium, Plutonium and other 14 elements (transuranium elements), which make a separate block in Mendeleev ′ s periodic table was a revolution in the Nuclear Chemistry. This enhancement in the periodic table raises a few questions in our mind:• Whether there is a limited number of elements that can co-exist either in nature or can be produced from artificial synthesis by using modern technique ?• What is the maximum number of protons and neutrons that of a nucleus ?• What is the next double shell closure nucleus beyond 208 Pb ?To answer these questions, first we have to understand the agent which is responsible to rescue the nucleus against Coulomb repulsion. The obvious reply is the shell energy, which stabilises the nucleus against Coulomb disintegration [2]. Many theoretical models, like the macroscopic−microscopic (MM) calculations to explain involve some prior knowledge of densities, single-particle potentials and other bulk properties which may accumulate serious error in the largely extrapolated mass region of interest. They predict the magic shells at Z=114 and N=184 [3,4,5,6] which could have surprisingly long life time even of the order of a million years [7,8,9,5,10]. Some other such predictions of shell-closure for the superheavy region within the relativistic and non-relativistic theories depend mostly on the force parameters [11,12].Experimentally, till now, the quest for superheavy nuclei has been dramatically rejuvenated in recent years owing to the emergence of hot and cold fusion reactions. In cold fusion reactions involving a doubly magic spherical target and a deformed projectile were used by GSI [13,14,15,16,17] to produce heavy elements upto Z = 110−112. In hot fusion evaporation reactions with a deformed transuranium target and a doubly magic spherical projectile were used in the synthesis of superheavy nuclei Z = 112−118 at Dubna [18,19,20,21,22,23,24]. At the production time of Z = 112 nucleus at GSI the fusion cross section was extremely small (1pb), which led to the conclusion that reaching still heavier elements will be very difficult. At this time, the emergence of hot fusion reactions usi...

Structural and decay properties of Z = 132, 138 superheavy nuclei

“…In Refs. [60,61] To analyze the structural properties of these isotopes, we made an attempt using deformed RMF calculations. It is well known that the superheavy nuclei are identified by α-decay in the laboratory followed by spontaneous fission.…”

“…These features are known by bubble, halo and cluster structures of the nuclei and may be observed in light to superheavy nuclei [65,66,67,68,69,70]. Here, we have plotted the density profile for neutron, proton and total matter (neutron plus proton) for some of the predicted closed shell nuclei [60,61] big hump at mid of the centre and the surface. To reveal such type of distribution and to gain an insight into the arrangement of nucleons, we make two-dimensional contour plots for 360 132 and 370 132 with three different shape configurations as given in Figs.…”

A Study of Multi-Λ Hypernuclei Within Spherical Relativistic Mean-Field Approach

“…[43] predicted the nuclear magicity at Z = 114, 120 and N = 172, 184, and 258 and the reconfirmation of closed shells at Z = 120 and N = 172, 184, 258 are given in Ref. [44]. The exhaustive investigations performed within the framework of continuum relativistic Bogoliubov theory [45] [46,47] over a wide range of even-even nuclei within spherical relativistic mean field approaches with semi-realistic interactions (M3Y-P6 and P7 parameter sets)has been made and they choose the proton(neutron) pairing energy correction and suggested the possible magicity features in the region Z = 14, 16,34,38,40,58,46,92,120,124,126 and N = 40, 56, 90, 124, 172, 178, 164, 184 which show remarkable agreements with the results in Refs.…”

Isoscalar giant monopole resonance for drip-line and super heavy nuclei in the framework of relativistic mean field formalism with scaling calculation

“…Thus, it is instructive to know the giant monopole resonance, compressibility modulus, and other related quantities for both drip-lines and super heavy nuclei. In this context, our aim is to study the giant monopole excitation energy and the compressional modulus of finite nuclei near the drip-line [4] as well as for recently discussed super heavy nuclei with proton numbers Z=114 and 120, which are predicted to be the next magic numbers beyond Z=82 with various models [12][13][14]. In addition, the calculations of Refs.…”