Presentation on theme: "ISOL Radioactive beams J Fragmentation beams E* Stable beams E* Time Out of the box?"— Presentation transcript:
ISOL Radioactive beams J Fragmentation beams E* Stable beams E* Time Out of the box?
Accuracy Précision I) Are nuclei at the limits of particle stability, beyond what can be measured today going to answer THE questions* ? How much beyond do we need to go and why ? Are there “ key “ nuclei? How much are we hampered by lack of P and A in the measurements ? Will looking at high precision data and detailed information help? Do we need to measure all observables measured using stable beams with Nuclei far from stability ? Do we have enough data today to look at in a consistent manner already to address THE questions* ? Did we fully exploit the data that we already have ? II) Are there new experimental methods that we need to invent ? What do you dream of measuring but cannot today? Is 10 days the maximum we can invest in an experiment today? How compelling is our need a next generation ISOL facility ? III) Do we need to understand (dynamics) - the beauty of the reaction mechanism Should we differentiate between authors/acknowledgment or go the Particle Physics way *THE questions
Summary: Status and perspectives * Multipole response of nuclei -Not much information for unstable nuclei so far -PDR problem, no GDR systematics, no GQR, no GMR -In principle, experimental techniques have been developed, need beams and investment ! --> RIBF, FAIR FRIB * EoS of asymmetric matter -Many attempts and constraints already; relation of observables to symmetry energy: model dependencies -> many methods? better theory? Changes along isotopic chains ?) -Heavy ion collisions with n-rich beams might provide info for higher densities how large is model dependence ? * Single-particle structure and correlations -How can we understand the quenching of s.p.-strength as a function of Sn-Sp ? -Can give QFS cross sections reliable information ? -Observables directly related to tensor/short-range correlations ? -E.g. experiments like p,2pn with radioactive beams * Drip line -Elaborated experimental techniques available -Haloes and states beyond drip line can be studied with high precision up to Z=8 now -Heavier haloes at RIKEN, later FIR and FRIB (starting 2020) * Stable nuclei -Many open questions even for stable nuclei, precision experiments needed, -also important to pursue with RIB experiments and interpretation * Reaction Theory ! Ab initio theory cross sections
Conclusions-Nasser Many-body theories have come a long way. These days, they can work with chiral nuclear forces as well. 3NF should be better understood though. New reaction theories based on these new developments should now be worked on. Light hadron scattering can be used at low momentum transfers to probe fundamental properties of nuclei such as density distributions, compressibility and in general collective properties, beta-decay rates etc. Equation of state of asymmetric matter is highly desired. Electron scattering from radioactive nuclei sheds light on charge-density distribution at low momentum transfers. BE(2) can be studied in several cases. Magnetic properties and QFS will prove to be very difficult with the present intensities. NOTE: This is only a subset of all nuclear-structure activities around the world.
Other questions Evolution of nuclear properties as fn of J,T Large acceptance spectrometer +next gen Gamma-arrays Spectroscopy of fission fragments Fission new variables (on the dynamics of fission) Tunnelling at the femtometer scale Pairing transfer reactions + Np pairing Experimental signatures for change of pairing as a function of isospin. Will the Search for new shell closures help inverse the problem to better define the interaction ?
Summary of talks Symmetry energy and skins (isovector) (e.g PDR …) difficulties to be overcome, complementary to HIC Drip line and beyond neutron unbound states …. Neutron radioactivity ? Nucleon –nucleon correlations Clustering e.g tetra n …, gaint halos’s (?) Single particle strengths quenching of spectroscopic factors … Electron scattering --> charge density distributions, BE(2) values if the intensities allow and then to more difficult channels (like magnetic properties or spectral functions) but then you really need high intensities. Low-q: matter density distributions, Giant resonances, Gamow-Teller resonances Need for 3NF ?
Where does the nuclear chart end? Is the concept of magicity still useful in SHN? How strong and localized are shells, e.g. N = 162, 184? Experimental confirmation of Z/A-assignment of SHN (Z=114-118) How to best produce more neutron-rich SHN? Are SHN formed in stellar nucleosynthesis? Key questions in SHN research Key Questions in SHN research (Micheal Bloch)
Cw accelerator for high-intensity stable beams (>10 14 /s) (thin) targets that can stand high-intensity (cw) beams sufficient material for additional actinide targets ( 254 Es, 251 Cf, …) Compact recoil separator to access short-lived SHN high-intensity radioactive beams (>10 10 /s) with good beam quality macroscopic amounts of transactinde elements Experimental challenges in SHN research
+ What happens when an exotic nuclei undergoes fast rotation The next Frontier of Nuclear Physics ? AIP Conf. Proc. 1498, 84 (2012 ) pn pn
EoS of asymmetric nuclear matter… time matters… Measure observables with high resolution + compare to models Space-time probes: Imaging at “femtoscopic scale”? “when” and “where” particles are produced? Clusterization + resonances at low ρ Dynamics & Spectroscopy - Clusters (multi-alpha,…) and unbound states affect EoS (Khan) - Spectroscopy? “in-medium” vs “free”? (ex. BE) Nucleon-nucleon interaction (2&3-Body forces, etc.) study also dynamics! Neutron Stars, Supernovae II (neutrinosphere, nucleosynthesis) Projectile Target Pre-equilibrium Fragmentation Resonance decays Clusters Large (N-Z) 2 (RIBS and Stable!) WHY? Asy-EoS: E(ρ n, ρ p,T)
Will the concept of single particle state picture fail at some stage ? Go towards heavy Nuclei Heavy nuclei below U Transfer reactions with high statistics ‘get the whole strength in a consistent way (Structure and reaction in the same frame work)?’ (extrapolated towards the drip line) Heavy nuclei below U Will there be a diminishing role of 2 body interaction and just be manifestions of manybody effects Role of 3 (4) body forces in destroying gaps ? Will Shell structure evolve to clusterization and fnally band structure of nuclei!!!! 10 to 30 MeV/u
large small matter overlap Coherent superposition Compound nucleus Quantum Decoherence ? Nuclear collisions – isolated, no external environment – internal environment from many complex excitations while merging M. Schlosshauer, Decoherence and the quantum to classical transition, Springer (2007) Dasgupta et al ANU Fusion cross- section (mb) System “ entangled ” with environment Loss of coherence in smaller system system Complex environment Sub-system Larger system Sub-system “entangled” with rest of system Exploring Quantum mechanics at the femtometer scale Decoherence, Tunneling of composite objects Is there anything new to learn ? Specaility of a nuclear system Strong interplay of many open and virtual channels This could be one way of looking at this
Questions about Pairing in weakly bound systems Matsuo PRC 73 (2006)044309 Separation Effects on Two-neutron transfer reactions (t,p) and (p,t) reactions in reverse kinematics. Do we expect an enhancement of the cross-section ? Skin Di-neutrons Correlation Length N. Pillet et al. PRC 76 (2007)024310 Role of isoscalar (T=0) and isovector (T=1) pairing Does isoscalar pairing give rise to collective modes? Direct reactions are unique tools in our experimental study of exotic nuclei Two particle transfer reactions provide specific tools to probe the amplitude of pairing collective modes Heavy Ion Transfer. Josephson effect?
in a phenomenological approach, one gets an enhancement factor significantly larger than usual for pure neutron transfer the Total Kinetic Energy Loss distributions show a concentration of strength close to the ground to ground state transitions The 60 Ni+ 116 Sn system - Transfer reactions studied at far sub-barrier energies with the PRISMA Spectrometer D.Montanari et al., INPC2013 and Fusion2014
To look for new Phenomena High spin Isospin weak binding (neutron rich not dripline) High Spin and High Isospin Technology +stable beams Excited states of of 400 Nuclei M,Z at one go AGATA_0.71 +VAMOS+++ Prompt spectroscopy of fission fragments will help us to probe excited states at BOTH relative high spin and isospin in heavier nuclei