Spin-Isospin excitations as quantitative constraint for the Skyrme tensor force

1. Spin-Isospin excitations as quantitative constraint for the Skyrme tensor force Chunlin Bai Department of Physics, Sichuan University Chengdu, China ● Skyrme parameter sets with tensor force ● Tensor effects on the excited states ● GT and SD constraint on the tensor force ● Tests of the constraint ● Recent studies in open-shell nuclei ● Conclusion and outlook KITPC, Jun 14th, 2012

2. Skyrme parameter sets with tensor force The tensor terms postulated by Skyrme: Nucl. Phy. 9, 615(1959) Skyrme parameter sets which include tensor force: Fl. Stancu et. al, PLB68, 108(1977), B. A. Brown et. al, PRC74, 061303(2006) G-Matrix interaction T >0, U>0 G. Colòet. al, PLB644, 227(1977), D. M. Brink et. al, PRC74, 061303(2006) Single-particle energies T >0, U<0 T ±, U ± Ground state properties T. Lesinski et. al. PRC76, 014312(2007) KITPC, Jun 14th, 2012

3. Tensor effects on GT states • Main peak • Low energy tail Bai , Sagawa, Zhang, Zhang, Colò, Xu, Phys. Lett. B675, 28(2009) KITPC, Jun 14th, 2012

4. Tensor effects on Charge-exchange SD Bai, Zhang, Sagawa, Zhang, Colò, Xu, PRL 105,072501(2010) Exp. From T. Wakasa et. al., PRC 84, 014614(2011) In T43, T >0, U<0 In SLy5+Tw, T>0, U>0 The SD 1- state is shifted downward dramatically by the tensor RPA correlations. KITPC, Jun 14th, 2012

5. Tensor effects in M1 excitations Cao, Colò, Sagawa, Bortignon, Sciacchitano, PRC 80, 064304 (2009) KITPC, Jun 14th, 2012

6. GT and SD constraint on the tensor force Bai, Zhang, Sagawa, Zhang, Colò, Xu, PRC83,054316(2011); The exp.main peak energy of SD and GT in 90Zr and 208Pb can be the constraints by requiring the condition ● In TIJ family, only T21, T32, T43, and T54 fulfill the condition; ● SD 1- states strongly constrain the value of T; ● Together with SD, GT main peak can be used to constrain value of U. KITPC, Jun 14th, 2012

7. Tests of the constraints by SD in 16O Bai, Sagawa, Colo, Zhang, Zhang, PRC 84, 044329(2011) KITPC, Jun 14th, 2012

8. Tests of the constraints by IVSM in 90Zr and 208Pb K. Miki et. al., PRL 2012 KITPC, Jun 14th, 2012

9. Recent studies in open-shell nuclei HFB+pnQRPA (canonical basis) calculation details: ● In HFB T=1 pairing is adjusted to reproduce the neutron pairing gap of 120Sn ● In HFB cut-off of the quasi-particle energy: 180 MeV ● In QRPA cut-off neutron states with Choosing of the pairing interaction: HFB pnQRPA The strength of the T=0 pairing is not well evaluated, In N. Vinh Mau, arXiv 0711, 3173 (2007), f=1.36, In our calculation f = 0.0, 0.5, 1, 1.5, 1.7 KITPC, Jun 14th, 2012

10. GT excitations in Sn isotopes T=0 pairing has almost no effect on the main peak energies. KITPC, Jun 14th, 2012

11. GT excitations in Sb isotopes KITPC, Jun 14th, 2012

12. Conclusion and outlook ● Main peak energy of GT and charge-exchange SD transitions in closed shell nuclei can supply good constraint for tensor force; ● In media heavy nuclei such as Sn isotopes, the T=0 pairing force has negligible effects on the main GT peaks; ● GT main peak of media heavy nuclei such as Sn isotopes can also supply good constraint for the tensor force; ●GT excitations in other isotopes and isotonics will be studied; ● Other spin-isospin excitations and the relevant quantities will be studied so as to find constraints for the tensor force. KITPC, Jun 14th, 2012

13. collaborators G. Colò, INFN , Italy K. Miki, RCNP, Japan H. Sagawa, Aizu univ. Japan F. R. Xu, PKU, China H. Q. Zhang, CIAE, China X. Z. Zhang, CIAE, China KITPC, Jun 14th, 2012

14. Many Thanks KITPC, Jun 14th, 2012