Nuclear structure and dynamics at the limits

1. Nuclear structure and dynamics at the limits Reiner Krücken for the NuSTAR collaboration Physik Department E12 Technische Universität München & Maier-Leibnitz-Laboratory for Nuclear and Particle Physics

2. RISING to the Challenges Bill Gelletly for the Surrey nuclear physics group Centre for Nuclear and Radiation Physics Physics Department University of Surrey UWS -08/05/2008

3. Nuclear structure and dynamics at the limits Introduction The NuSTAR facility at the Super-FRS Modification of shell structure Soft modes, nuclear EOS and neutron skins Conclusions

4. Long Standing Questions of Nuclear Structure Physics • What are the limits for existence of nuclei? • Where are the proton and neutron drip lines situated? • Where does the nuclear chart end? • How does the nuclear force depend on varying proton-to-neutron ratios? • What is the isospin dependence of the spin-orbit force? • How does shell structure change far away from stability? • How to explain collective phenomena from individual motion? • What are the phases, relevant degrees of freedom, and symmetries of the nuclear many-body system? • How are complex nuclei built from their basic constituents? • What is the effective nucleon-nucleon interaction? • How does QCD constrain its parameters? • Which are the nuclei relevant for astrophysical processes and what are their properties? • What is the origin of the heavy elements?

5. Towards a predictive (and unified) description of nuclei • Mean Field Models • DFT • RMF Shell Model w/ configuration interaction • Ab initio • GFMC • NCSM • CC • Effective interactions • Vlow-k, VUCOM, G-matrix (+3N) • Realistic interactions • AV18, CD Bonn + 3N • cEFT

6. Superheavy elements Neutron skins 2n New shell gaps through residual interaction Shell quenching by diffuse surface 9Li 11Li harmonic oscillator + spin-orbit +centrifugal diffuse surface neutron rich + spin-orbit New shell gaps through residual interaction Soft collective modes Halos Nuclear Structure at the extremes

7. Primary Beams • 1012/s; 1.5-2 GeV/u; 238U28+ • Factor 100-1000 over present in intensity Secondary Beams Storage and Cooler Rings • Broad range of radioactive beams • up to 1.5 - 2 GeV/u; • up to factor 10 000 in intensity over present • Antiprotons • Radioactive beams • e- - A and Antiproton-A collider FAIR: Facility for Antiproton and Ion Research Future Facility SIS 100/300 GSI today SIS 18 UNILAC ESR 100 m HESR Super FRS RESR CR NESR

8. Primary Beams Superferric Multiplet • 1012/s; 1.5-2 GeV/u; 238U28+ • Factor 100-1000 3 x 9.75° SC Dipole Unit Secondary Beams • up to factor 10 000 SUPERconducting FRagment Separator

9. Decay spectroscopy (DESPEC) Laser spectroscopy (LASPEC) Precision mass measurements (MATS) Gas stopping cell In-flight spectroscopy (HISPEC) Energy buncher / spectrometer Experiments with slowed and stopped beams

10. High Energy BranchReactions with Relativistic Radioactive Beams (R3B) Reactions in complete kinematics

11. Ring Branch

12. Modification of shell structure Reduction of Spin-orbit splitting ? Role of the tensor interaction ?

13. Shell modification through softer potential ? T.R. Werner, J. Dobaczewski, W. Nazarewicz, Z. Phys. A358 (1997) 169 Possible signatures:  reduction of spin-orbit splitting in neutron-rich nuclei  new shell gaps (e.g. N=70 in 110Zr)  increased neutron skin

14. How to find a shell gap: Sn values Neutron separation energies Pairing Pb Isotopes Shell closure Neutron dripline Neutron number N

15. Q-values from b-decay (DESPEC)  Shortest half-lives, production rates << 1 min-1

16. 1.5 d 1.0 <r 2 > Isotope shifts (fm 0.5 2 ) 0.0 Laser spectroscopy and precision masses (MATS &LASPEC)  highest precision masses 25  Spins, Moments  isotope shifts Rb 20 (MeV) 2-neutron separation energy 15 2n S 10 40 45 50 55 60 65 D. Lunney et al. Rev. Mod. Phys. 75 (2003) 1021 N ( Z = 37)

17. time Schottky Mass Spectrometry 4 particles with different m/q Y. Litvinov

18. Sin(w1) Sin(w2) w4 w3 w2 w1 Sin(w3) time Sin(w4) Schottky Mass Spectrometry Fast Fourier Transform Y. Litvinov

19. Schottky Frequency in Storage Ring (ILIMA)

20. ILIMA mass measurements mass surveys

21. b-decay Q-value:  130Cd less bound  Quenching of N=82 shell I. Dillmann, PRL91 (2003) 162503 N=82 Probing shell closures: Decay Spectroscopy (DESPEC) • no shell quenching • information on excited states needed !! A. Jungclaus et al., PRL 99, 132501 (2007)

22. j’> j’< j> neutrons j< protons T. Otsuka et al., PRL 95 (2005) 232502 11/2- 7/2+ Reduced spin-orbit or tensor force? 1h11/2 protons 1g7/2 protons Z=51 Sb isotopes RIB beams J.P. Schiffer et al., PRL 92 (2004) T. Otsuka et al., PRL 97 (2006) 162501 1h11/2 neutrons

23. DL=3 DL=1 f 5/2 p 1/2 p 3/2 DL=1 x GXPF1A x PRELIMINARY 56Ti Single-particle structure from direct reactions g (HISPEC, R3B) • Knock-out reaction • Peripheral collision • Possible with few particles/s P|| Momentum distribution: - L of knocked-out particle A. Gade • Cross sections: • exclusive for excited states via gamma-decay ( AGATA) •  spectroscopic factors P. Maierbeck et al.,GSI-FRS + MINIBALL

24. Soft modes, nuclear EOS and neutron skins

25.  probe bulk properties of nuclei in-medium modification of NN interaction symmetry energy compressibility New soft modes Giant resonances Radioactive beams allow study of isospin dependence

26. Dipole Excitations of Neutron-Rich Nuclei- Symmetry Energy, Neutron Skin, and Neutron Stars - P. Ring et al. Photoabsorption LAND collaboration A. Klimkiewicz, PRL subm. P. Adrich, PRL 95 (2005) 124Sn Coulomb excitation 130Sn 132Sn neutron skin  core vibration

27. Rn-Rp δr Dipole Excitations of Neutron-Rich Nuclei- Symmetry Energy, Neutron Skin, and Neutron Stars - Neutron-skin thickness excitation of the neutron skin Properties of Neutron Stars

28. Neutron skins Alternative access to asymmetry parameter M. Bender, et al. RMP 75 (2003) • established methods for charge radii • neutron radii difficult to measure

29. Electron Ion Collider (ELISe) to FLAIR from RESR • charge densities from (e,e) scattering • collective modes via (e,e’) scattering • single-particle structure from (e,e’N) reactions

30. The EXL experiment RIB‘s from the Super-FRS Electron cooler Inelastic a scattering  Isoscalar Giant Monopole resonance  isospin dependence of incompressibility Elastic proton scattering  Matter distribution

31. p A A-1 Neutron skins from Antiprotons Antiproton Ion Collider (AIC) EXOpbar • annihilation cross-section at high energies proportional to mean square radius • count surviving A-1 nuclei •  Proton and neutron radii in the same experiment M. Wada, Y.Yamazaki • antprotons on atomic orbits • annihilation on tail of density distribution •  Halo or Skin ? H. Lenske, P. Kienle PLB647 (2007) 82 P. Kienle, NIM B 214 (2004) 193

32. 205Pb Neutron skins  Deeply bound pionic states Pion-Nucleus Optical potential related to neutron skin  In medium modification of pion decay constant  In medium modification of quark condensate Kolomeitsev et al. PRL90 (2003) 092501

33. The aims of NUSTAR @ FAIR • Nuclear Structure Physics: • Isospin dependence of effective nuclear interaction • Modification of shell structure far off stability • New effects near the driplines (halos, skins, soft modes, …) • Relevant symmetries, structural evolution, role of phase transitions • Nuclear Astrophysics Studies: • Understand the origin of the heavy elements • K.H. Langanke • Nuclear Reaction studies • Investigate reaction dynamics for RIB production, spallation, ADS • Dynamics in systems with weakly bound nucleons (halos, correlations, continuum)  Towards a unified description of nuclear structure and dynamics