Double pion production in NNNN and NˉN\bar{N}N collisions

With an effective Lagrangian approach, we give a full analysis on the $NN \to NN\pi\pi$ and $\bar{N}N\to \bar{N}N\pi\pi$ reactions by exploring the roles of various resonances with mass up to 1.72 GeV. We find large contributions from $\Delta$, $N^*(1440)$, $\Delta(1600)$ and $\Delta(1620)$ resonances. Our calculations also indicate sizeable contributions from nucleon poles for the energies close to the threshold. A good description to the existing data of different isospin channels of $NN\to NN\pi\pi$ and $\bar{N}N\to \bar{N}N\pi\pi$ for beam energies up to 2.2 GeV is reached. Our results provide important implications to the ABC effect and guildlines to the future experimental projects at COSY, HADES and HIRFL-CSR. We point out that the \={P}ANDA at FAIR could be an essential place for studying the properties of baryon resonances and the data with baryon and anti-baryon in final states are worth analyzing.Comment: Invited plenary talk at the 11th International Workshop on Meson Production, Properties and Interaction (MESON2010), 10-15 June, 2010, Krakow, Polan

Potential energy surfaces of actinide and transfermium nuclei from multi-dimensional constraint covariant density functional theories

Multi-dimensional constrained covariant density functional theories were developed recently. In these theories, all shape degrees of freedom \beta_{\lambda\mu} deformations with even \mu are allowed, e.g., \beta_{20}, \beta_{22}, \beta_{30}, \beta_{32}, \beta_{40}, \beta_{42}, \beta_{44}, and so on and the CDFT functional can be one of the following four forms: the meson exchange or point-coupling nucleon interactions combined with the non-linear or density-dependent couplings. In this contribution, some applications of these theories are presented. The potential energy surfaces of actinide nuclei in the (\beta_{20}, \beta_{22}, \beta_{30}) deformation space are investigated. It is found that besides the octupole deformation, the triaxiality also plays an important role upon the second fission barriers. The non-axial reflection-asymmetric \beta_{32} shape in some transfermium nuclei with N = 150, namely 246Cm, 248Cf, 250Fm, and 252No are studied.Comment: 7 pages, 6 figures; invited talk at the International Conference on Nuclear Structure and Related Topics, Jul 02-July 7, 2012, Dubn