[en] This document presents 2 features of nuclei, first their amazing diversity in terms of structure, shape or stability and secondly the fact that we can create new heavy nuclei through collisions between lighter nuclei. Oganesson is now the heavier element created on earth it is made up of 118 protons and was produced in a particle accelerator at Dubna (Russia) through collisions between impinging ⁴⁸Ca ions on a californium target. The actual quest is to reach a predicted island of stability whose super-heavy elements would have an half-life of at least several years according to Oganessian, Y.. About half a dozen of accelerator facilities in the world are able to produce heavy nuclei. (A.C.)

[en] Emergence of superheavy nuclei and hypernuclei, two fields of intense research in nuclear physics, has made a big impact on the nuclear chart; while the discovery of the superheavy oganesson has completed the seven full rows of the periodic table, discovery of several exotic hypernuclei have added a third dimension, called strangeness, to the existing nuclear chart. Highlights of some recent developments in these two fields are presented. (author)

[en] In nuclear physics, superheavy and hypernuclei are two of the most important fields of research. In the fifties, a new kind of nucleus, called hypernucleus, was discovered. Recent discovery of a strange nucleus, called anti-hypertrion, has enabled extension of the nuclear chart into three dimensions

[en] On December 30, IUPAC issued a statement confirming the discovery of four new elements that make their official entry and complete the seventh row of the periodic table. After reviewing the various scientific papers published between 2004 and 2012 describing these newcomers, IUPAC and its physics equivalent, IUPAP, concluded that the criteria for the discovery of elements 113, 115, 117 and 118 were met. So the periodic table, the superstar of chemistry textbooks that adorns many chemistry lab walls and science classrooms, has changed its face

[en] The discovery of the elements 113, 115, 117 and 118 was announced on december 30. 2015 by the UICPA (International Union of Pure and Applied Chemistry). This announcement was based on the conclusions of an expert group the Joint Working Party (JWP) and became soon polemical as some scientists began questioning the quality of the assessment and the fact that the UIPPA (International Union of Pure and Applied Physics) had not been informed before the announcement. In order to avoid some future misunderstandings, the UICPA and the UIPPA have agreed on a procedure to implement officially any new element. In the new procedure, published in may 2018, the chairmen of UICPA and UIPPA have the possibility of examining the conclusions of the JWP before any announcement, they can also lead their own peer assessment and draw their own conclusions. (A.C.)

[en] The last line of the Mendeleev table is now completed and the last elements that have been discovered are nihonium (Nh), moscovium (Mc), tennessine (Ts) and oganesson (Og) with the following atomic numbers: Z= 113, 115, 117 and 118 respectively. They have been obtained in the collision of 2 heavy ions and have undergone very quick alpha decay. For instance only 3 nuclei of nihonium were obtained during a 550 day-long target bombarding by ions. We are reaching the limits of the present method to produce them but atomic physics considerations foresee the existence of atoms up to Z=172. The article describes the quest for ever heavier elements and shows that the next step will be to optimize the present method by increasing at any stage of the process (ion beam production, ion collision, separation and identification) the number of useful events. The Super Separator Spectrometer: S³, a device designed for experiments with the very high intensity ion beams delivered by the future linear accelerator Spiral2 (at GANIL) will contribute to this quest. (A.C.)

[en] Trans-actinides with Z ≥ 103 are called super-heavy nuclei (SHN). SHN was synthesized in the laboratory by cold or hot fusion reactions. Oganesson is the heaviest element discovered so far and three isotopes of Og with mass number, A=293-295 are known to date. Exploration of the upper limit of the nuclear chart is a great challenge faced by nuclear physicists nowadays. In the present work, we have studied the alpha decay chains of the isotopes of the superheavy element, Oganesson (Og) with Z = 118 using the Effective Liquid Drop model (ELDM). Similar decay chains can be observed for other isotopes. ELDM predicts 2-α-chains whereas, other semi-empirical formulae predicts 3α- chains from ^293-295Og isotopes. Our predictions may help the experimentalists in their further research on the quest for new SHN

[en] Since the discovery of α-decay, it has contributed immensely to the understanding of nuclear physics. Being a dominant mode of decay in superheavy nuclei, α-decay is of pronounced importance for the experimental studies. The heaviest element with proton number Z=118 (²⁹⁷Og) was experimentally synthesized through the α-decay process, and many more efforts are going on along this direction. In this regard, the already known experimental observation of decay chain of ²⁹³Lv and theoretical speculation of α-decay from ²⁹⁷Og by Deng et al. manifest the possibility of detection of nucleus ²⁹⁷Og. In this work, we have probed the α-decay from ²⁹⁷Og by using new modified Horoi formula (NMHF), new modified Sobiczewski formula (NMSF), and new modified Manjunatha formula (NMMF) from the recent work

[en] The α-decay half-lives of synthesized superheavy nuclei (SHN) from seaborgium to oganesson are calculated by employing the generalized liquid-drop model (GLDM), the Royer formula and the universal decay law (UDL) with experimental α-decay energies Q${}_{\mathrm{\alpha <!--\; ??\; -->}}$. For the GLDM, we consider the shell correction. The agreement between the experimental data and the calculations indicates that all the methods we used are successful to reproduce α-decay half-lives of known SHN. The decay-modes of known nuclei on the ${}^{294}$Og decay-chain are also consistent with the experiments. For the unknown nuclei, the α-decay half-lives have been predicted by inputting Q${}_{\mathrm{\alpha <!--\; ??\; -->}}$ values extracted from the newest Weizsäcker-Skyrme-4 (WS4) model. In the GLDM with shell correction, we adopt the constant α-preformation factor P${}_{\mathrm{\alpha <!--\; ??\; -->}}$ as well as P${}_{\mathrm{\alpha <!--\; ??\; -->}}$ extracted by Cluster Formation Model (CFM). To calculate CFM P${}_{\mathrm{\alpha <!--\; ??\; -->}}$ values, we use FRDM binding energies and WS4 mass excess values. The relationship of P${}_{\mathrm{\alpha <!--\; ??\; -->}}$ and Q${}_{\mathrm{\alpha <!--\; ??\; -->}}$ shows that ${}^{294,296,314,316,320}$Og isotopes are relatively stable. The competition between α-decay and spontaneous fission is discussed in detail for ${}^{283-<!--\; ???\; -->339}$Og isotopes. The decay-chains of ${}^{290-<!--\; ???\; -->300}$Og have also been presented. Since the α-decay half-lives of ${}^{283-<!--\; ???\; -->303}$Og isotopes are obviously lower than their spontaneous fission half-lives by more than 6 orders, these isotopes would mainly have α-decay. The ${}^{306-<!--\; ???\; -->334}$Og isotopes may undergo spontaneous fission. The nuclei ${}^{304,305}$Og would have both α-decay and spontaneous fission. By the shell-effect included GLDM with CFM P${}_{\mathrm{\alpha <!--\; ??\; -->}}$, we predict ${}^{295}$Og undergoes α-decay and T${}_{\mathrm{\alpha <!--\; ??\; -->}}^{1/2}$=0.37 ms. The ${}^{296}$Og is also α-decay and has T${}_{\mathrm{\alpha <!--\; ??\; -->}}^{1/2}$=0.40 ms.

[en] The α-decay energies (Q_α) and α-decay half-lives of the odd-even superheavy nuclei (SHN) with Z = 119 within the range 285 ≤ A ≤ 303 have been systematically calculated, and the studies are performed by using 5 mass models and 3 empirical formulas, respectively. The heaviest element known so far is Z = 118 and any further progress in the synthesis of new elements with Z > 118 is not quite evident, even though attempts to synthesize the isotopes ^298,299120 was performed by Oganessian et al. in 2009. As the question on the border of the elements’ existence remain unanswered, the synthesis and identification of new elements remains a hot topic in nuclear physics. the present theoretical study on Z = 119, the most hopeful new element with Z > 118 to be synthesized in the near future, along with our earlier works, ensures the validity of our models, and these findings will provide a new guide for future experiments