High spin physics- achievements and perspectives S. Frauendorf IRP, Research Center Dresden-Rossendorf, Germany and Department of Physics University of Notre Dame, USA

The frontiers fission 1)Path to fission I 3)Isospin multiplets 6)The future p-dripline 5) Weak symmetry breaking A=130 SHE A 2) Triaxiality 4) Bands and isomers around A=250 N-Z n-dripline Terra incognita

1)Path to fission New shells: TSD Triaxial Strongly deformed Symmetries decide: irregularbandsspin-parity sequence

Disappearance and recurrence of rotational bands Courtesy M. Riley

Courtesy M. Riley E.Paul et al. PRL 98, 012501 (2007)

First evidence for hyperdeformation?

wobblers the Z=70,71 N=94,97 gaps Courtesy M. Riley

p-h excitation Why are they different? no wobbling wobbling

2) Triaxiality

Spectroscopy of fragments From spontaneous Cf fission X.Y. Luo et al., PLB, in review I. Stefanescu et al., NPA, in press

p=- chiral p=+ wobbler

Consequence of chirality: Two identical rotational bands.

Best case of chirality so far: chiral vibrations in S. Zhu et al. Phys. Rev. Lett. 91, 132501 (2003) 15

Chiral vibrations in 135-Nd TAC+RPA calculations Mukhopadhyay, Almehed et al. PRL 99, 172501 (2007) Phonon is mainly orientation fluctuations Same inband transition rates - Good agreement with experiment 16

135-Nd Transition rates in-band cross band 17

3)Isospin multiplets

4) Bands and isomers around A=250 Pretty robust

Condensation of Octupole phonons + Two phonon - One phonon + 27 X. Wang, R.V.F. Janssens, I. Wiedenhoever et al. to be published. Preliminary + 27

5) Weak symmetry breaking Chiral vibrations Rotation induced condensation of octupole phonons Tidal waves How does the nucleus rotate?

Rotation induced condensation of octupole phonons S. Frauendorf Phys. Rev. C 77, 021304 (07) Two components: Quadrupole +Octupole 23

Weak coupling + Two phonon - One phonon + 27 X. Wang, R.V.F. Janssens, I. Wiedenhoever et al. to be published. Preliminary + 27

Intermediate coupling missing 27

Strong coupling 28

1.Weakly oriented nuclei – tidal waves S. Frauendorf, Y. Gu, arXiv 0709.0254, PRL, in preparation Mean field: rigid spherical soft rigid deformed -condensation of quadrupole phonons -very soft rotor Tidal wave 4 Yrast line irregular multi p-h regular w weakly increases with I regular w proportional to I

How does orientation come about? Orientation of the gyroscopes Deformed density / potential Nucleonic orbitals – gyroscopes Deformed potential aligns the partially filled orbitals Partially filled orbitals are highly tropic Nuclus is oriented – rotational band Well deformed 5

How does the nucleus rotate? Angular momentum is generated by alignment of the spin of the orbitals with the rotational axis Gradual – rotational band Abrupt – band crossing, no bands Moments of inertia for I>20 (no pairing) differ strongly from rigid body value Microscopic cranking is the way to calculate the response of the gyros. Quantization of spin of orbits responsible for difference. Microscopic cranking Calculations do well in reproducing the moments of inertia. With and without pairing. 7 M. A. Deleplanque et al. Phys. Rev. C69, 044309 (2004)

What have we learned? Liquid drop + shell structure in rotating WS – like potential account for energies and lifetimes. Time-odd terms of the mean field? Deviations from classical droplet are dramatic. Symmetries of the mean field play a central role Dynamical (weak) symmetry breaking is common.

6)The future Combination of large Gamma ray arrays with stable and radioactive beams

The challenges (incomplete) fission Map out the new shells I Rotation induced T=0 pairing? Ergodic bands (Mottelson, Matsuo,Yoshida) p-dripline Cold proton emission from high spin states Dynamics of angular momentum reorientation A=130 SHE A Increased stability of High spin isomers N-Z n-dripline Terra incognita Decoupling of mass from charge Increased stability of K-isomers Single particle states from isomers