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Nuclear structure and dynamics at the limits

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 & DFG Cluster of Excellence Origin and Structure of the Universe.

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Nuclear structure and dynamics at the limits

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  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 & DFG Cluster of Excellence Origin and Structure of the Universe

  2. 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

  3. 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?

  4. Towards a predictive (and unified) description of nuclei Vlow-k, VUCOM (+3N) AV18, CD Bonn + 3N cEFT

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

  6. How do stars explode? 15 Msun A. Marek & H.-Th. Janka • 2D phenomena essential – post-shock convection • Shock revival by delayed neutrino heating • Onset of explosion fostered by standing accretion shock instability (SASI) Next steps: • Modeling nucleosynthetic output of the explosions • extending models to more massive stars • towards 3D models • nuclear physics input for nucleosynthesis

  7. CS22892-052 (Sneden et al. 2003) solar r abundance log(X/H)-12 element number Explosive nucleosynthesis runs through exotic nuclei • Nuclear shell structure • Defines r-process path • Imprinted in abundance pattern • maybe modified for exotic nuclei Pfeiffer et al. r - process • Fission may fill the holes • Depends on shell structure as well • (need info on fission barriers  LMU) G. Martinez-Pinedo et al.

  8. 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

  9. Transmission SUPERconducting FRagment Separator

  10. 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

  11. High Energy BranchReactions with Relativistic Radioactive Beams (R3B) RIB Reactions in complete kinematics High Resolution measurement • Target • Tracker • Calorimeter Neutrons Protons Heavy fragments Large acceptance dipole

  12. Ring Branch

  13. Topic 1:Modification of shell structure Reduction of Spin-orbit splitting ? Role of the tensor interaction ?

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

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

  16. Q-values from b-decay (DESPEC) • Shortest half-lives, production rates << 1 min-1 • low precision

  17. 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)

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

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

  20. Schottky Frequency in Storage Ring (ILIMA)

  21. ILIMA mass measurements mass surveys

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

  23. 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

  24. g P|| A. Gade 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 (HISPEC, R3B) • Knock-out reaction • Peripheral collision • relativistic energies • Possible with few particles/s • Momentum distribution: • L of knocked-out particle • Cross sections: • exclusive for excited states • via gamma-decay ( AGATA) •  spectroscopic factors P. Maierbeck (TUM) et al.,GSI-FRS + MINIBALL

  25. Topic 2:Soft modes, nuclear EOS and neutron skins

  26.  probe bulk properties of nuclei symmetry energy compressibility effective NN interaction Giant resonances Radioactive beams allow study of isospin dependence New:  Soft Modes

  27. 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

  28. Pygmy strength Asymmetry a4 [MeV] Dipole Excitations of Neutron-Rich Nuclei- Symmetry Energy, EOS and Neutron Stars - excitation of the neutron skin RQRPA N. Paar

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

  30. Electron Ion Collider (ELISe) e-LINAC from RESR NESR • charge densities from (e,e) scattering • multipolarities of collective modes via (e,e’) scattering • single-particle structure from (e,e’N) reactions

  31. The EXL experiment RIB‘s from the Super-FRS Electron cooler Inelastic a scattering (worldwide unique)  Isoscalar Giant Monopole Resonance  Isospin dependence of incompressibility Elastic proton scattering  Matter distribution

  32. 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

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

  34. The aims of NuSTAR @ FAIR Nuclear Structure, Astrophyiscs, and Reactions • 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 • Nuclear Reaction studies • Investigate reaction dynamics for RIB production, spallation, ADS • Dynamics in systems with weakly bound nucleons (halos, correlations, continuum, low density nuclear matter)  Towards a unified description of nuclear structure and dynamics

  35. Thank you for your attention!!

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