Decay of superheavy nuclei based on the random forest algorithm

How nuclides decay in the superheavy region is key information for investigating new elements beyond oganesson and the island of stability. The Random Forest algorithm is applied to study the competition between different decay modes in the superheavy region, including $\alpha$ decay, $\beta^-$ decay, $\beta^+$ decay, electron capture and spontaneous fission. The observed half-lives and dominant decay mode are well reproduced. The dominant decay mode of 96.9 % nuclei beyond $^{212}$Po is correctly described. $\alpha$ decay is predicted to be the dominant decay mode for isotopes in new elements $Z = 119 - 122$, except for spontaneous fission in some even-even ones because of the odd-even staggering effect. The predicted half-lives show the existence of a long-lived spontaneous fission island at the southwest of $^{298}$Fl caused by the competition of nuclear deformation and Coulomb repulsion. More understanding of spontaneous fission, especially beyond $^{286}$Fl, is crucial to search for new elements and the island of stability.

[1]  C. Yuan,et al.  Investigation of $$\beta ^-$$ β - -decay half-life and delayed neutron emission with uncertainty analysis , 2023, Nuclear Science and Techniques.

[2]  J. Gheller,et al.  Observation of a correlated free four-neutron system , 2022, Nature.

[3]  JiangJun He,et al.  Shell-model study on properties of proton dripline nuclides with Z, N = 30–50 including uncertainty analysis , 2022, Chinese Physics C.

[4]  W. Nazarewicz,et al.  Machine Learning in Nuclear Physics , 2021, 2112.02309.

[5]  J. Gu,et al.  Improved effective liquid drop model for α-decay half-lives , 2021, Nuclear Physics A.

[6]  Xiaopeng Dong,et al.  Novel Bayesian neural network based approach for nuclear charge radii , 2021, Physical Review C.

[7]  C. Nithya,et al.  Decay modes of superheavy nuclei using a modified generalized liquid drop model and a mass-inertia-dependent approach for spontaneous fission , 2021 .

[8]  P. K. Sharma,et al.  A new empirical formula for α-decay half-life and decay chains of Z = 120 isotopes , 2021, Physica Scripta.

[9]  Z. Zhang,et al.  Ion-optical design and multiparticle tracking in 3D magnetic field of the gas-filled recoil separator SHANS2 at CAFE2 , 2021, Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment.

[10]  F. Kondev,et al.  The NUBASE2020 evaluation of nuclear physics properties , 2021, Chinese Physics C.

[11]  H. Sagawa,et al.  Calculation of nuclear charge radii with a trained feed-forward neural network , 2020 .

[12]  S. Patra,et al.  Search for the stable isotopes for Z = 119 and 121 superheavy elements using relativistic mean field model , 2020, Physica Scripta.

[13]  Alessandro Pastore,et al.  Trees and Forests in Nuclear Physics , 2020, Journal of Physics G: Nuclear and Particle Physics.

[14]  B. Hu,et al.  Ab initio no-core Gamow shell-model calculations of multineutron systems , 2019, Physical Review C.

[15]  Z. Niu,et al.  Comparative study of radial basis function and Bayesian neural network approaches in nuclear mass predictions , 2019, Physical Review C.

[16]  A. Soylu.  Search for decay modes of heavy and superheavy nuclei , 2019, Chinese Physics C.

[17]  W. Nazarewicz,et al.  Colloquium : Superheavy elements: Oganesson and beyond , 2019, Reviews of Modern Physics.

[18]  H. Ramalingam,et al.  Search for possible fusion reactions to synthesize the superheavy element Z=121 , 2018, Physical Review C.

[19]  Jun Su,et al.  Predictions for the synthesis of superheavy elements Z=119 and 120 , 2018, Physical Review C.

[20]  W. Nazarewicz.  The limits of nuclear mass and charge , 2018, Nature Physics.

[21]  Toshio Suzuki,et al.  Evolution of shell structure in exotic nuclei , 2018, Reviews of Modern Physics.

[22]  David J. Schwab,et al.  A high-bias, low-variance introduction to Machine Learning for physicists , 2018, Physics reports.

[23]  Z. Niu,et al.  Nuclear mass predictions based on Bayesian neural network approach with pairing and shell effects , 2018, 1801.04411.

[24]  X. Bao,et al.  Predictions of decay modes for the superheavy nuclei most suitable for synthesis , 2017 .

[25]  Wei-Chia Chen,et al.  Nuclear charge radii: density functional theory meets Bayesian neural networks , 2016, 1608.03020.

[26]  H. B. Prosper,et al.  Nuclear mass predictions for the crustal composition of neutron stars: A Bayesian neural network approach , 2015, 1508.06263.

[27]  H. Sagawa,et al.  Nuclear ground-state masses and deformations: FRDM(2012) , 2015, 1508.06294.

[28]  Jinhu Dong,et al.  Competition between α-decay and spontaneous fission for superheavy nuclei , 2015 .

[29]  P. Möller,et al.  Fission barriers at the end of the chart of the nuclides , 2015 .

[30]  J. Meng,et al.  Surface diffuseness correction in global mass formula , 2014, 1405.2616.

[31]  F. Hessberger,et al.  Discovery of the heaviest elements. , 2013, Chemphyschem : a European journal of chemical physics and physical chemistry.

[32]  Z. Ren,et al.  Stability of superheavy nuclei against α-decay and spontaneous fission , 2013 .

[33]  M. Kortelainen,et al.  The limits of the nuclear landscape , 2012, Nature.

[34]  Gaël Varoquaux,et al.  Scikit-learn: Machine Learning in Python , 2011, J. Mach. Learn. Res..

[35]  Stefan M. Wild,et al.  Nuclear Energy Density Optimization , 2010, 1005.5145.

[36]  K.Heyde,et al.  Shell evolution and nuclear forces , 2010, 1002.1006.

[37]  K. Santhosh,et al.  Semi-empirical formula for spontaneous fission half life time , 2010 .

[38]  Toshio Suzuki,et al.  Novel features of nuclear forces and shell evolution in exotic nuclei. , 2009, Physical review letters.

[39]  C. Asawatangtrakuldee,et al.  Microscopic mechanism of charged-particle radioactivity and generalization of the Geiger-Nuttall law , 2009, 0909.4495.

[40]  R. Liotta,et al.  Universal decay law in charged-particle emission and exotic cluster radioactivity. , 2009, Physical review letters.

[41]  Z. Ren,et al.  Competition between α decay and spontaneous fission for heavy and superheavy nuclei , 2008 .

[42]  J. Suhonen.  From Nucleons to Nucleus: Concepts of Microscopic Nuclear Theory , 2007 .

[43]  Z. Ren,et al.  Spontaneous fission half-lives of heavy nuclei in ground state and in isomeric state , 2005 .

[44]  L. Breiman.  Random Forests , 2001, Encyclopedia of Machine Learning and Data Mining.

[45]  G. Royer.  Alpha emission and spontaneous fission through quasi-molecular shapes , 2000 .

[46]  Z. Niu 牛,et al.  Research on α-decay for the superheavy nuclei with Z= 118–120 , 2022 .

[47]  F. Kondev,et al.  The AME 2020 atomic mass evaluation (II). Tables, graphs and references , 2021, Chinese Physics C.