1. Nuclear moments of excited states. Recent results, developments and perspectives. Nuclear moments of isomeric states – results ~ N=40 from projectile-fragmentation reactions (GANIL and MSU); How to reach the short-lived (<50 ns) isomers? transfer reactions (Orsay) developments deep-inelastic/multi-nucleon transfer regime – experiment to be performed soon in LNL What about the picoseconds states? High-Velocity Transient Field (HVTF) at GANIL on the 2 + in 72 Zn – work in progress Can LNS contribute to the TF measurements? Summary and perspectives

2. G. Georgiev, CSNSM, Orsay Introduction Nuclear moments and their sensitivities: magnetic dipole moments single-particle structure – proton/neutron character, active orbitals, spin-flip contributions to the wave function electric quadrupole moments collective properties and nuclear deformation Experimental methods and requirements Time-Dependent Perturbed Angular Distribution (TDPAD) initial spin-aligned ensemble external field for perturbation change in the angular distribution Transient Field method extremely high magnetic fields – many kTesla (provided by the movement of the ions through a ferromagnetic host) Coulomb excitation with a particle-gamma correlations observed change in the angular distribution

3. G. Georgiev, CSNSM, Orsay N=40 shell closure? High 2 + energy (R. Broda et al., PRL 74 868 (95)) Low B(E2) (0+  2+) value (O. Sorlin et al. PRL 88, 92501 (2002)) Mass-measurements and S 2n values show no kink at N=40 (C. Guenaut et al., PR C75, 44303 (07)) Increased collectivity with addition of just two particles. (O. Perru et al. PRL 96, 232501 (2006)) Our approach – probing the purity of the wave functions and the deformation through nuclear moment measurements

4. G. Georgiev, CSNSM, Orsay TDPAD on 67 Ni and 69 Cu @ GANIL 1999 g( 69 Cu) exp. = 0.225(25) g( 67 Ni ) exp. = 0.125(6) low signal-to-noise ratio First measurement in projectile fragmentation G. Georgiev et al., JP G28, 2993 (2002)

5. G. Georgiev, CSNSM, Orsay Magnetic and quadrupole moments of 61m Fe g( 61 Fe,9/2 + ) =-0.229(2) I.Matea et al., PRL 93, 142503 (2004) 654 keV 207 keV |Q s ( 61 Fe,9/2 + )| = 0.41(6) b N. Vermeulen et al., PR C75, 51302 (2007) First Q moment measurement in projectile fragmentation

6. G. Georgiev, CSNSM, Orsay Beyond N=40 – 70 Ni at MSU g ( 70 Ni) exp. = -0.320 (15) 76 Ge beam @ 130 MeV/u 9 Be target A1900 fragment separator ~90% beam purity 4 SeGA detectors data for 70 Ni taken during ~12 hours

7. G. Georgiev, CSNSM, Orsay 65 Ni in transfer reaction - Orsay Ge BaF 2 g( 65 Ni) exp. = - 0.296(3) G. Georgiev et al., EPJ A30, 351 (2006) (d,p) reaction 2 Ge and 2 BaF 2 detectors enriched 64 Ni/ 62 Ni (ferromagnetic) target

8. G. Georgiev, CSNSM, Orsay Comparison experiment vs. theory LSSM calculations using 48 Ca core and free-nucleon g factors: very good agreement with 63 Ni, 65 Ni significant contributions from proton excitations across Z=28 61 Fe – less well reproduced 63 Ni, 65 Ni, 70 Ni and 61 Fe fitting well in the g 9/2 g-factor systematics in the region S.Lunardi et al., PR C76, 34303 (2007) N.Hoteling et al., PR C77, 44314 (2008) g factors Vermeulen et al., PR C75, 51302 (2007) Q moment LSSM calculations with canonical effective charges reproduce well the experimentally determined Q moment Two possible scenarios in mean-field calculations K = 1/2 or K = 9/2 with very similar quadrupole moments Q s = -0.36 b vs. Q s = -0.46 b Q exp. = |0.41(6)| b Spectroscopic studies of the isomeric band point towards prolate defformation

9. G. Georgiev, CSNSM, Orsay How to reach the shorter-lived isomers? E. Fiori, M.Sc. Thesis, Univ. Camerino Spin alignment in deep-inelastic reactions previously observed T. Pawlat et al., LNL Ann. Rep. (1994) 8 Spin alignment in deep-inelastic reactions previously observed T. Pawlat et al., LNL Ann. Rep. (1994) 8 32 S beam on 40 Ca target well above the CB 32 S beam on 40 Ca target well above the CB for 43m Sc strong alignment observed for 43m Sc 335 MeV 76 Ge on 70 Zn target 335 MeV 76 Ge on 70 Zn target (Ni or Au backing) 4 Ge detectors in a horizontal plane 4 Ge detectors in a horizontal plane electromagnet electromagnet (0.05 – 0.7 T) Experiment to be performed at LNL within the next few months

10. G. Georgiev, CSNSM, Orsay g factors of 2 + states around N=40 – what can we learn? Ni (Z=28) – semi-magic nuclei Zn (Z=28+2) Z/A up to N=40 for the 2 + Ge (Z=28+4) – consistent with Z/A line Theories (Strasbourg-Madrid; M. Hjorth-Jensen; B.A. Brown et al.) predict a deviation from Z/A – can it be observed experimentally and where? g factors of 2 + states – a measure for the interplay between the single-particle and collective properties in the nuclei

11. G. Georgiev, CSNSM, Orsay The TF method A.E. Stuchbery, PR C69, 64311 (2004) beam ++ -- ±±  B ext Larmor frequency  /g = (  N ·B·t eff ) /ħ Precession angle:  =  L t eff G att. – empirical att. factor B 1s = 16.7*K*Z 3 Tesla q 1s - H-like fraction p 1s  ???

12. G. Georgiev, CSNSM, Orsay Experimental setup determination of θ angular distribution particle detector 3°<α<5.5° mask target beam (10 5 p/s) 25° 125° 155° -60° 90° -25° -125° -155°

13. G. Georgiev, CSNSM, Orsay 72 Zn and 76 Ge – work in progress θ Ge = 11 ± 5 mradθ Zn = 16 ± 5 mrad g(2 +, 72 Zn) – very similar to the one of 76 Ge B(HVTF) of Zn/Ge in Gd – 5 times smaller than expected (cause p 1s ) B(HVTF) of Zn/Ge in Fe – no effect observed

14. G. Georgiev, CSNSM, Orsay TF and LNS? @LNS A systematic study of B tf as a function of Z and v ion is of crucial importance

15. G. Georgiev, CSNSM, Orsay Summary and perspectives g factors - very sensitive probes for small admixtures in the nuclear wave functions g factors - very sensitive probes for small admixtures in the nuclear wave functions g(2 + ) fingerprint of the interplay between collective and single-particle properties g(2 + ) fingerprint of the interplay between collective and single-particle properties Q moments – direct information on the deformation Q moments – direct information on the deformation Developments are on the way and still more need to be done in order to reach more and more exotic nuclei Developments are on the way and still more need to be done in order to reach more and more exotic nuclei

16. G. Georgiev, CSNSM, Orsay Collaborations CSNSM, Orsay, France E. Fiori, R. Lozeva, S. Cabaret University of Camerino, Camerino, Italy and INRNE, BAS, Bulgaria* D.L. Balabanski*, G. Lo Bianco, A. Saltarelli CE Bruyères le Châtel, France J.M. Daugas, G. Belier, V. Meot, O. Roig The Weizmann Institute of Science, Israel M. Hass, G. Goldring, N.S. Bondilli, V. Kumar GANIL, Caen, France E. Clement, G. De France, F. De Oliveira Santos, S. Grevy, M. Lewitowicz, C. Stodel Department of Nuclear Physics, ANU, Canberra, Australia A. Stuchbery Dep. Física Teórica, Univ. Autónoma de Madrid, Spain A. Jungclaus, V. Modamio, J. Walker CENBG, Bordeaux-Gradignant, France I. Matea, M. Tarisien IKS, KU Leuven G. Neyens, N. Vermeulen, D. Yordanov IPN, Orsay, France S. Franchoo, F. Ibrahim, F. Le Blanc, B. Mouginot, L. Perrot, O. Sorlin, I. Stefan, M. Stanoiu, D. Verney NSCL, MSU, USA P. Mantica, W. Mueller, T. Ginter, M. Hausman, A. Stolz FLNR, JINR, Dubna, Russia S. Lukyanov, Yu. Penionzhkevich, Yu. Sobolev ISK, Universitaet Bonn, Germany K.H. Speidel, J. Leske IKS, Univ. Cologne, Germany A.Blazhev University of Sofia, Bulgaria M. Danchev Univ. Ioannina, Greece T. Mertzimekis

17. G. Georgiev, CSNSM, Orsay

18. Experimental conditions Snow at GANIL in April???