ab-initio alpha-alpha scattering

Transcription

1 ab-initio alpha-alpha scattering Elhatisari et al., Nature 528, 111 (215)

2 S2n (MeV) The frontier: neutron-rich calcium isotopes probing nuclear forces and shell structure in a neutron-rich medium 52 Ca mass TITAN@TRIUMF Gallant et al, PRL 19, 3256 (212) AME23 TITAN K Ca Sc Neutron Number N 54 Ca S 2n (MeV) Ca: 2 protons, 34 neutrons Experiment ISOLTRAP NN+3N (MBPT) CC (Hagen et al.) KB3G GXPF1A ISOLTRAP@CERN Wienholtz et al, Nature (213) 54 Ca mass Neutron number N CC theory Hagen et al., PRL19, 3252 (212) RIBF@RIKEN Steppenbeck et al Nature (213)

3 Anomalous Long Lifetime of 14 C Determine the microscopic origin of the suppressed β-decay rate: 3N force.29 Maris et al., PRL 16, 2252 (211) GT matrix element N3LO NN only N3LO + 3NF (c D = -.2) N3LO + 3NF (c D = -2.) s p sd pf sdg pfh sdgi pfhj sdgik pfhjl configuration space Dimension of matrix solved for 8 lowest states ~ 1 9 Solution took ~ 6 hours on 215, cores on Cray XT5 Jaguar at ORNL

4 ORNL, University of Tennessee, Michigan State University, Chalmers University of Technology, TRIUMF, Hebrew University, Technical University Darmstadt, University of Oslo, University of Trento

5 Fusion of Light Nuclei Computational nuclear physics enables us to reach into regimes where experiments and analytic theory are not possible, such as the cores of fission reactors or hot and dense evolving environments such as those found in inertial confinement fusion environment. Ab ini+o theory reduces uncertainty due to conflic+ng data NIF The n- 3 H elastic cross section for 14 MeV neutrons, important for NIF, was not known precisely enough. Delivered evaluated data with required 5% uncertainty and successfully compared to measurements using an Inertial Confinement Facility First measurements of the differential cross sections for the elastic n- 2 H and n- 3 H scattering at 14.1 MeV using an Inertial Confinement Facility, by J.A. Frenje et al., Phys. Rev. Lett. 17, (211)

6 Configuration interaction techniques light and heavy nuclei detailed spectroscopy quantum correlations (lab-system description) Input: configura+on space + forces NN+NNN interac+ons Matrix elements figed to experiment Renormaliza+on Method Diagonaliza+on Trunca+on+diagonaliza+on Monte Carlo Observables Direct comparison with experiment Pseudo-data to inform reaction theory and DFT

7 Average one-body Hamiltonian 12 Sn Unbound states Coulomb barrier Discrete (bound) states ε F ε F Surface region n p A i=1 Flat bottom H ˆ = h i, h i = 2 2M 2 i +V i h i φ k ( i) = ε k φ k i ( )

8 ˆ H = t i i Nuclear shell model v ij = (t i +V i ) i, j i i j + $ & & % ' V ) i ) i ( 1 2 v ij i, j i j One-body Hamiltonian Construct basis states with good (J z, T z ) or (J,T) Compute the Hamiltonian matrix Diagonalize Hamiltonian matrix for lowest eigenstates Number of states increases dramatically with particle number Full fp shell for 6 Zn : J z states 5,53,594 J =,T = states 81,84, 784 J = 6,T =1 states Can we get around this problem? Effective interactions in truncated spaces (P-included, finite; Q-excluded, infinite) Residual interaction (G-matrix) depends on the configuration space. Effective charges Breaks down around particle drip lines Residual interactioni P + Q =1

9 Microscopic valence-space Shell Model Hamiltonian Energy (MeV) Coupled Cluster Effective Interaction (valence cluster expansion) CCEI 4 + Exp. 22 O USD G.R. Jansen et al., Phys. Rev. Lett. 113, (214) Energy (MeV) In-medium SRG Effective Interaction O 4 + MBPT IM-SRG NN+3N-ind IM-SRG NN+3N-full 4 + (4 + ) ( ) ( ) Expt. S.K. Bogner et al., Phys. Rev. Lett. 113, (214)

10 Diagonalization Shell Model (medium-mass nuclei reached;dimensions 1 9!) Honma, Otsuka et al., PRC69, (24) Martinez-Pinedo ENAM 4

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