Effect of tensor on halo and subshell structure in Ne, O and Mg isotopes Chen Qiu Supervisor: Prof. Xian-rong Zhou Xiamen University April. 13, 2012

Content Introduction Theoretical Framework Result and discussion Summary

The shell structure of nuclei has formed a fundamental basis for understanding their properties. O, Ne and Mg has abundance of orbit near drip line. Tensor correlation plays an important role on the properties of finite nuclei. Introduction

Why consider tensor force ? Theoretical framework G.Colo, H.Sagawa et.al,PLB,646,(2007)227

June 9 th 2009, Japan RIKEN center found halo structure of 31 Ne Introduction

Theoretical framework Hartree-Fock equation Skyrme interaction Tensor force

Hartree-Fock theory Skyrme-Hartree-Fock equation: Theoretical framework Slater determinant 1-body density matrix The unknown exact energy is set equal (ansatz!) to a much simpler expectation value on a Slater determinant.

The energy density founctional for centeral exchange and tensor part ： is the spin density Theoretical framework Tensor Force:

Numerical detail Apply harmonic oscillator basis to solve equation Given pairing force:V 0 = -410MeV Use different skyrme parameter sets Theoretical framework Skyrme force para. sets with tensorwithout tensor SLy5+TSLy5 T31,T41SLy4 T24,T44SGII ……

Results and discussion Bulk properties of Ne isotopes Halo structure in 31 Ne Density distribution of Ne isotopes Shell structure of N=16 Result and discussion

Ne isotopes(deformation value:beta) SLy5 and SLy5+T both give spherical shape at 30 Ne 34 Ne is drip line nucleus Result and discussion

Ne isotopes Di-neutron separation energy can fit experimental data well except for SGII Calculated Result is between the error range of Japan RIKEN Result and discussion

Ne isotopes (radii) Slope of neutron radius changes steep at 18 Ne --- Shell effect Slope of neutron radius changes steep at 30 Ne ---halo ??? Result and discussion

Ne isotopes (neutron density distribution) Neutron density has no abnormal changes at r axis. Neutron density has significant dispersion at z axis Result and discussion

Binding energy per A of O and Mg Result and discussion Calculation of Mg can fit experiment data well. Calculation of O is over experimental data.

Mg isotopes Odd-even difference is well reproduced. Curve steep changes at N=16 with tensor. Result and discussion

O isotopes Calculation with tensor can fit experimental data at N=16 to N=18 perfect. Result and discussion

Summary: Calculation obtains unstable 31 Ne halo structure. Calculation reveals that 31 Ne is prolate deformation. N=16 could be a subshell between N=8 and N=20 Summary