Nuclear structure notes on element 115 decay chains

Abstract

The nuclear matrix elements for neutrinoless double beta decay AIP Conf. Proc. 942, 77 (2007) Abstract. Hitherto collected data on more than hundred α-decay chains stemming from element 115 are combined to probe some aspects of the underlying nuclear structure of the heaviest atomic nuclei yet created in the laboratory.

Decay studies of heavy and superheavy nuclei

“…Two experiments were performed recently, one at GSI and a second at LBNL, using the 48 Ca+ 243 Am reaction to create isotopes of element-115, notably 288 115 via the three-neutron evaporation channel. Combining the results from the two experiments, more than seventy chains of decays were observed and assigned to the decay of this isotope [6][7][8]10]. It was already known that there was a fine structure observed in the decay [11] indicative of it passing through both the ground states and excited states in daughter isotopes belonging to these chains.…”

“…It is well known that the hindrance factor [27] arising from the odd particle, whether proton or neutron, is typically of the order of 10 3 to 10 5 . There are very few cases where the odd-odd neighbour has a useful value, or limit, placed on the fission hindrance arising from the two odd particles, but it seems reasonable to expect that the effect of each odd particle is to contribute such that the odd-odd character would result in hindrances of ∼10 8 . One then can suggest that it would be reasonable to expect a fission hindrance for a two quasiparticle high-K state to be about 10 3 relative to the ground state.…”

“…2 of Ref. [8] to see the spectra and their interpretations). The fact that there is no apparent X-ray spectrum observed is important since it indicates that many transitions identified in these nuclei are not highly converted and most likely have electric dipole character.…”

“…First, I briefly discuss the latest -ray spectroscopy of the decay chains of 288 115 [6][7][8], and the implications that such studies have on the knowledge of single-particle states. This leads on to a more general discussion of the predictions of theoretical models, especially concerning the occurrence and extent of a e-mail: rmclark@lbl.gov Comparison of Theories NL1 NL1*Meff Mic-Mac Figure 1.…”

First Study on Nihonium (Nh, Element 113) Chemistry at TASCA

“…Nh isotopes for chemistry studies can be produced as decay products following nuclear fusion reactions between 48 Ca and 243 Am or 249 Bk targets resulting in the production ofisotopes of Mc (element 115) and Ts (element 117) isotopes, respectively ( Oganessian and Utyonkov, 2015 ). The nuclear reaction 243 Am ( 48 Ca,3n) 288 Mc has a higher cross section of about 10 pb ( Oganessian et al, 2013 ; Rudolph et al, 2013 ; Rudolph et al, 2014 ; Gates et al, 2015 ; Rudolph et al, 2015 ; Forsberg et al, 2016 ). The second member of the decay chain, 284 Nh, is accessible for chemical studies after an α -decay of the short-lived mother nuclide 288 Mc.…”