Volume 82, Number 1, April 2008
Article Number 12001
Number of page(s) 6
Section Nuclear Physics
Published online 13 March 2008
EPL, 82 (2008) 12001
DOI: 10.1209/0295-5075/82/12001

Evolution of nuclear shell structure due to the pion exchange potential

WenHui Long1, 2, Hiroyuki Sagawa2, Jie Meng1, 3 and Nguyen Van Giai4, 5

1  School of Physics, Peking University - 100871 Beijing, China
2  Center for Mathematical Sciences, University of Aizu - Aizu-Wakamatsu, 965-8580 Fukushima, Japan
3  Department of Physics, University of Stellenbosch - Stellenbosch, South Africa
4  CNRS-IN2P3, UMR 8608 - F-91406 Orsay Cedex, France, EU
5  Université Paris-Sud - F-91405 Orsay, France, EU

received 1 October 2007; accepted in final form 12 February 2008; published April 2008
published online 13 March 2008

The evolution of nuclear shell structure is investigated for the first time within density-dependent relativistic Hartree-Fock theory and the role of $\pi $-exchange potential is studied in detail. The energy differences between the neutron orbits $\{\nu 1h_{9/2}, \nu 1i_{13/2}\}$ in the N=82 isotones and between the proton ones $\{\pi 1g_{7/2}, \pi 1h_{11/2}\}$ in the Z=50 isotopes are extracted as a function of neutron excess N - Z. A kink around Z=58 for the N=82 isotones is found as an effect of pion correlations. It is shown that the inclusion of $\pi $-coupling plays a central role to provide substantial isospin dependence of the energy differences. In particular, the tensor part of the $\pi $-coupling has an important effect on the characteristic isospin dependence observed in recent experiments.

21.30.Fe - Forces in hadronic systems and effective interactions.
21.60.Jz - Nuclear Density Functional Theory and extensions (includes Hartree-Fock and random-phase approximations).
24.10.Cn - Many-body theory.

© EPLA 2008