Lawrence Livermore National Laboratory Nuclear Structure and ISOL - PowerPoint PPT Presentation

Lawrence Livermore National Laboratory Nuclear Structure and ISOL Facilities Erich Ormand Nuclear Theory & Modeling Group Lawrence Livermore National Laboratory, P. O. Box 808, L-414, Livermore, CA 94551 This work performed under the auspices of the U.S. Department of Energy by UCRL-PRES- 400431 Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344

Low-Energy Nuclear Physics Research  Overarching goal: To arrive at a comprehensive and unified microscopic description of all nuclei and their low-energy reactions from the basic interactions between the constituent protons and neutrons This is a lofty and ambitious goal that has been a “Holy Grail” in • physics for over fifty years “Unified” does not mean that there is a single theoretical method that • will work in all cases − Self-bound, two-component quantum many-fermion system − Complicated interaction with at least two- and three-nucleon components − We seek to describe the properties of “nuclei” ranging from the deuteron to super-heavy nuclei and neutron stars Symbiosis between theory and experiment • − Experiment without theory is just a collection of information − Theory without experiment is just playing around Lawrence Livermore National Laboratory 2 UCRL-PRES- 400431

Nuclear physics and the fate of the Universe  Nuclear reactions are amongst the Supernova 1987A most important in the universe • They are responsible for all the matter we can see in the universe  Big bang Nothing much heavier than • lithium  Star formation • Fusion of light-ions can make elements up to Iron Triple-alpha reaction to make • “How were the elements from iron to ow were the elements from iron to 12 C uranium made? uranium made?” -- one of the -- one of the ‘Eleven leven  Supernovae (?) Science Questions for the N Science Questions for the New ew • Rapid neutron capture to make Century Century’ [ Connecting Quarks with the all elements up to Uranium Cosmos , Board on Physics and Astronomy, National Academies Press, 2003] Lawrence Livermore National Laboratory 3 UCRL-PRES- 400431

Physics of exotic nuclei and the formation of the elements  Rapid neutron capture followed by beta decay to the valley of stability  But much is unknown Masses • Beta-decay lifetimes • Neutron capture rates • Heavy elements are made with with − Density of states neutron capture − Gamma strength functions  Big question question Where does the r-process • Nuclear properties are occur? important in determining the fate of the universe Lawrence Livermore National Laboratory 4 UCRL-PRES- 400431

The evolution of shell structure Our concept shell closures is Experimental excitation Shell gaps and nucleosynthesis energies for 2 + states probably not as universal as we once thought Dobaczewski et al., PRC 53, 2809 (1996) Dip at N=82, why? RIB facilities will help determine the RIB facilities will help determine the properties of shell structures, but properties of shell structures, but theory is essential. theory is essential. Lawrence Livermore National Laboratory 5 UCRL-PRES- 400431

What do we need?  More experimental data and better theories Structure Theory • − Masses − Beta-decay lifetimes − Level densities − Shell structures Reaction Theory • − Optical potential − Multi-step direct reactions theory − Break up − Surrogates − Pre-equilibrium emission  Experiment can’t do it all, and theory can’t do it without experiment to validate the theories Lawrence Livermore National Laboratory 6 UCRL-PRES- 400431

Tools of the future - Experiment  New RIB facilities RIKEN • GSI FAIR • EURISOL • GANIL • ISAC-TRIUMF • FRIB (aka RIA) •  Capabilities Re-accelerated beams • Fast beams • Lawrence Livermore National Laboratory 7 UCRL-PRES- 400431

Tools of the future - Theory  Moore’s law is a theorist’s best friend Name # Procs Mem/proc Tflops BlueGene/L (1) 65536 256MB 367 Purple (6) 12288 4GB 93 Atlas (19) 9216 2GB 44 Jaguar (2) 23016 2GB 119 High-performance computing is giving us a tool that can revolutionize our approach to theoretical physics Lawrence Livermore National Laboratory 8 UCRL-PRES- 400431

Nuclear Many-Body Problem Energy, Density, Complexity Sea of Ignorance Sea of Ignorance heavy heavy nuclei nuclei few few body body quarks quarks gluons gluons vacuum vacuum quark-gluon quark-gluon many body systems many body systems nucleon few body systems few body systems nucleon soup soup effective NN force effective NN force free NN force QCD QCD free NN force QCD QCD Lawrence Livermore National Laboratory 9 UCRL-PRES- 400431

The Beginning - The Interaction quarks quarks gluons gluons Lawrence Livermore National Laboratory 10 UCRL-PRES- 400431

The Beginning - The Interaction Effective-field theory (EFT)  Inter-nucleon potentials Paris, Argonne, • Bonn, etc. − Potentials with parameters fit to scattering and 9 parameters bound state data Effective-field theory • − Guided by QCD 2 parameters with pion exchange with parameters fit to data − Order-parameter, (Q/ Λ ) n - N n LO 24 parameters 0 parameters EFT- two-body N 3 LO, χ 2 / ν ~ • V low-k 1: Entem et al., PRC68, 041001 (2003) Lawrence Livermore National Laboratory 11 UCRL-PRES- 400431

The Beginning - The Three-body Interaction N 2 LO 3-body C E C D  Also Illinois potential GFMC - S. Pieper & • B. Wiringa Question:  Can it solve the A y • puzzle? Is the NNN • interaction the origin Preference is C D ~ -1 - 0 of spin-orbit physics But, C D and C E are note well determined at N 2 LO in nuclei? Lawrence Livermore National Laboratory 12 UCRL-PRES- 400431

Ab initio descriptions of light nuclei few few body body quarks quarks gluons gluons Lawrence Livermore National Laboratory 13 UCRL-PRES- 400431

Can we get around this problem? Effective interactions  � Choose subspace of for a calculation ( P -space) n • Include most of the relevant physics • Q -space (excluded - infinite)  Effective interaction: Q P H eff ˆ � i = E i ˆ P P � i − Bloch-Horowitz 1 ˆ ˆ ˆ ˆ H P H P H Q H P = + ˆ eff E Q H � i − Lee-Suzuki: H eff H eff = = P P X X H H X X -1 -1 P P Q X X H H X X -1 -1 P P=0 =0 Q Lawrence Livermore National Laboratory 14 UCRL-PRES- 400431

Deficiency of the NN interaction! 10 B is one of the most important tests as all realistic N is one of the most important tests as all realistic NN- 10 interactions fail to give the correct ground state interactions fail to give the correct ground state Lawrence Livermore National Laboratory 15 UCRL-PRES- 400431

Three-body to the rescue  Spin-orbit physics is coming from  While the contact terms prevent collapse Binding Energy (MeV) Exp: -64.7507(3) Thy: -64.03* * Convergence study not completed Level ordering is in overall agreement with experiment. Level ordering is in overall agreement with experiment. 12 C to to 16 O use ~ 6 use ~ 6000 CPU hours with 3-body! 000 CPU hours with 3-body! 12 To be consistent we need to go to N To be consistent we need to go to N 3 LO? O? Lawrence Livermore National Laboratory 16 UCRL-PRES- 400431

The three-body interaction and level ordering  No-core Shell Model (NCSM) Oscillator basis N max h � • Effective interaction with Okubo-Lee-Suzuki transformation • Computationally challenging with three-body • − N max =6; N basis ~ 32M; 700M NNN m.e.; 6TB; 90TF; N max =8 → 1.5 PF Lawrence Livermore National Laboratory 17 UCRL-PRES- 400431

The three-body interaction and transitions  M1 and Gamow-Teller are sensitive to the three-body interaction Lawrence Livermore National Laboratory 18 UCRL-PRES- 400431

Reactions with the No-core Shell Model  Light-ion fusion reactions  First generation method Not fully ab initio • Compute radial-cluster overlaps with • NCSM Woods-Saxon potential to fix Navratil, et al. PRC73, • 065801 (2006) asymptotic behavior and resonant state Resonating group method (RGM)  P 3/2 Fully ab initio • P 1/2 S 1/2 Lawrence Livermore National Laboratory 19 UCRL-PRES- 400431

Experiments to refine ab initio pictures  Three-body interaction is poorly constrained Masses and structure of drip-line nuclei are needed to help • constrain the isospin structure of the three-body interaction Gamow-Teller and M1 transitions to constrain the spin-orbit • components of the three-nucleon interaction Lawrence Livermore National Laboratory 20 UCRL-PRES- 400431

Beyond Light Nuclei heavy heavy nuclei nuclei few few body body quarks quarks gluons gluons Lawrence Livermore National Laboratory 21 UCRL-PRES- 400431