Theory Challenges at the Spiral2 horizon. Denis Lacroix. Outline:

Transcription

1 Theory Challenges at the Spiral2 horizon Denis Lacroix Outline: Experimental context Improvement of the description of nuclear reaction phenomena Emergent aspects in weakly bound systems Open questions and future of low energy nuclear physics.

2 (H. Savajols) Nuclear Physics within 10 years Nuclei at the frontiers Spiral 1 upgrade (P. Delahaye) Nuclei at the extreme of mass Physics along N=Z Proton rich nuclei Neutron rich nuclei

3 Progress in Nuclear reaction Theory at the SPIRAL2 Horizon (H. Savajols) Exotic nuclei production Proton rich nuclei Super-heavy Elements Low energy beam (E/A < 10 MeV) Competition between transfer reaction, Deep inelastic, fusion, quasi-fission and fission Some recent theoretical progress

4 Dynamical description of superfluid nuclei Recent progress Nuclear motion of superfluid nuclei on a mesh (3 groups in the world) time Applied to a number of physical process Vibrations Fusion/Transfert 48 Ca 40 Ca Scamps, Tanimura, Lacroix ( ) Fission time

5 Recent progress on fission Role of superfluidity 258 Fm Scamps Simenel, Lacroix, PRC 92 (2015) Tanimura, Lacroix, Scamps, PRC 92 (2015) 1 zs = s

6 relative yield Combining microscopic approach and phase-space exploration V) relative yield relative yield TKE (MeV) Lacroix, Ayik, EPJA (Review) 50 (2014) Experience vs Theory (a) Qini 2 = 160 b 125 b expt. TDDFT (a) Q 2 ini = 160 b 125 b expt. Tanimura, Lacroix, Ayik, submitted to PRL Constrains: -Generates a sample of microscopic trajectories (typically 300) -Each trajectory is 8-10 days CPU time (b) TKE (MeV) TDDFT A H /A TKE (MeV) fragment mass (b)

7 Progress in Nuclear reaction Theory at the SPIRAL2 Horizon (H. Savajols) Exotic nuclei production Proton rich nuclei Super-heavy Elements Physics of exotic nuclei New phenomena Few challenges for nuclear structure theory For the next 10 years

8 Binding energy The physics of exotic nuclei Weakly bound neutron rich nuclei How organizes neutron and proton matter in neutron rich systems? What we know/expected: Continuum Nombre de neutrons Stable Nuclei can have anomalous Extension: Exotic New excitation modes can emerge (?) New excitation modes Soft mode

9 The physics of exotic nuclei Weakly bound neutron rich nuclei How organizes neutron and proton matter in neutron/proton rich systems? What if we directly access the neutron density? Quantum droplet physics PRL 2016 Neutron star physics From A. Brown Gives direct information on the isospin properties of nuclei Physics of systems at anomalously large scattering length (close to unitary regime) Systems at very low density Pairing effects, continuum and other correlations

10 The physics of exotic nuclei Resonantly interacting systems and new radioactivity? From bound to unbound systems (passing the emission threshold) Correlation effect Quantum Chaos Statistical mechanics and level density in stable and unstable nuclei Resonance and correlations Minimal Cooper pair Quantum Order Exotic Physics at or below the Particle emission threshold Physics of deeply bound state at very large asymmetry Neutron rich Proton rich

11 Quantum Chaos -Yes- The physics of exotic nuclei Resonantly interacting systems and new radioactivity? From bound to unbound systems (passing the emission threshold) Correlation effect Can new radioactivity exists? Quantum Order Exotic Minimal Cooper pair 2p-radioactivity Search for the existence of new radioactivity? 2 neutron radioactivity? Multi-neutron radioactivity? Requires dedicated approaches in the continuuum (Gamow technique, Berggren technique, ) Kisamori et al PRL 116 (2016)

12 The physics of exotic nuclei Proton rich side Resistance of spin-isospin symmetry in nuclei SU(4) p n p n Symmetry destroyed by Coulomb Spin-orbit And tensor Coexistence of particle like and neutron-proton pairing in nuclei? p p Gezerlis et al, PRL 106 (2011) Competition with quarteting? p n p n Origin of clustering in nuclei? n n

13 The physics of exotic nuclei Exploring the transition from liquid nuclei to quasi-molecular states Extended Ikeda diagram W. von Oertzen, EPJA (2001) Deformed systems J.-P. Ebran et al, Nature 487 (2012) Experiments Low density systems Hoyle state Borderie et al PLB (2016) Girod, Schuck, PRL111 (2013)

14 The physics of exotic nuclei Fermi liquid versus quasi-molecular states: some present and future questions Clustering versus shape coexistence Heyde & Wood Rev. Mod. Phys. 83 (2011) 1467 Clarify the link between clusters and shape coexistence Competition between Pairing and quarteting in nuclei Organization of matter: Coexistence between incompressible liquid, aggregates in nuclei and neutron gas New symmetries and quantum correlations: Direct observation Yannouleas et Lanzman, Rep. Prog. Phys. (2007)

15 Binding Energy Nuclear physics today Emerging phenomena and theoretical challenges Correlated system VS Independent Particles system Exotic nuclei challenging theoretical physics Open mesoscopic systems Enhanced effect of correlations and continuum Continuum state Neutron number Stable In medium interaction Exotic

16 Traditional single-particle Shell picture Nuclear physics today Shell structure and Nuclear interactions Breakdown of magicity Competing effects close to drip-line Spin-orbit Tensor interaction (B. Sherrill, Ecole Joliot Curie 2011) Role of 3-body interaction unbound

17 Nuclear physics today Towards less-empirical approach to low energy nuclear physics Starting point : Chiral Lagrangian Epelbaum et al, arxiv: Feynman diagrams Direct link to QCD (chiral) Systematic Constructive method Consistent NN, 3N, 4N

18 Nuclear physics today Towards less-empirical approach to low energy nuclear physics Can we probe sub-nucleonic degrees of freedom with low energy nuclear data? Neutron matter EOS Symmetric matter EOS Increased complexity Low energy constant? Fit on nuclei Convergence And power counting Drischler, Hebeler, and Schwenk Phys. Rev. C 93 (2016)

19 Nuclear physics today Towards less-empirical approach to low energy nuclear physics Can we probe sub-nucleonic degrees of freedom with low energy nuclear data? Increased complexity Low energy constant? Fit on nuclei ( 16 O added for the fit) Convergence And power counting Identify key experiments What about the unification of theory for nuclei?

20 Summary Improvements of relevant reaction mechanisms: fusion, fission, transfert, Progress in the understanding of low energy small and large amplitude dynamics -Isospin effects, high neutron concentration, weak binding, Probing sub-nucleonic degrees of freedom with low energy nuclear data? Understanding the interaction between nucleons from first principle How organizes neutron and proton matter in neutron rich systems? Physics of systems at anomalously large scattering length (close to unitary regime) Systems at very low density Pairing effects, continuum and other correlations Coexistence of particle like and neutron-proton pairing in nuclei, quarteting and origin of clustering in nuclei? Search for the existence of new radioactivity?