Theory Group Plans and Highlights

Transcription

1 CANADA S NATIONAL LABORATORY FOR PARTICLE AND NUCLEAR PHYSICS Owned and operated as a joint venture by a consortium of Canadian universities via a contribution through the National Research Council Canada Theory Group Plans and Highlights Achim Schwenk Theory Group Leader, TRIUMF Affiliate Prof. University of Washington, Joint Institute for Nuclear Astrophysics (JINA) LABORATOIRE NATIONAL CANADIEN POUR LA RECHERCHE EN PHYSIQUE NUCLÉAIRE ET EN PHYSIQUE DES PARTICULES Propriété d un consortium d universités canadiennes, géré en co-entreprise à partir d une contribution administrée par le Conseil national de recherches Canada

2 Group overview presently 3 scientists: J. Ng, R. Woloshyn, A. Schwenk D. Morrissey starting fall 2009 (particle phenomenology) search in nuclear theory/astro (committee recommendation made) will bring group size back to 2005 need to replace B. Jennings position + 1 position in in nuclear theory (astro/symmetries) research in nuclear (4) and particle (3) theory successful RAs J. Braun 6-year position at U of Jena; S. Baroni joint INT, now Seattle 4 new RAs this fall: D. Mohler (Graz), A. Spray (Cornell), S. Tulin (Caltech), hopefully E. Jurgenson (OSU) increase in students (6 from SFU, UBC, Acadia, ) M. Ku (M.Sc. 2009) MIT, K. Hally (B.Sc. 2009) Tomlinson Fellowship 2009 March 13 ACOT Meeting 2

3 Recent successes organization of workshops in 2008 TeV-scale neutrino physics (J. Ng et al.) interdisciplinary INT program on coupled cluster theory (50 years of CC) TSI on modern methods and challenges in the physics of nuclei TRIUMF-GSI/FAIR workshop on future collaborations (J. Dilling and A.S.) unique training/research experience for students in Canada co-op/undergrad positions most popular in summer program since 2006, opens new horizons for students from small Canadian universities invited talks at main and most conferences/workshops includes plenary talks at ENAM08 and PANIC08 part of major international initiatives: JINA, UNEDF 2009 March 13 ACOT Meeting 3

4 Plans next exciting era with D. Morrissey and new hire ensure their successful start and help/support in all possible ways need to improve computing: dedicated theory cluster, essential for successful research program of new hire and RAs training future leaders in subatomic theory increase number of students to 1-2 per scientist exploit more synergies with experimental program establish Theory Group as center of activity for the broader Canadian subatomic theory community plenary talk at CAP09, invited talks APS NW (at UBC), TC5, sabbatical of S. Godfrey, NP Joint Positions Task Force improve Theory Group web presence run 3 workshops (LHC theory, lattice QCD, isospin-sym breaking) 2009 March 13 ACOT Meeting 4

5 Recent highlights nuclear forces and the renormalization group: universal low-momentum interactions, among top 5 cited papers in nuclear structure/reactions theory since 2002, used by >15 groups worldwide three-nucleon forces and neutron-rich nuclei: helium halo nuclei (talk by S. Bacca), location of the neutron drip line advances in nuclear matter theory: first direct convergence, provides key guidance for 15M$ US SciDAC project to construct a universal energy density functional for nuclei (unedf.org), first DFT results with microscopic pairing functional strongly-interacting matter in the cosmos: first neutrino rates for supernovae based on chiral effective field theory, light nuclei in supernovae and proto-neutron-star atmospheres nuclear theory impact on other fields: universal properties at the interface of nuclear physics and ultracold atoms 2009 March 13 ACOT Meeting 5

6 The nuclear forces frontier development of systematic effective field theory for nuclear forces and renormalization group evolution to apply to all nuclei EFT/RG interactions: top workhorses in nuclear theory, connected to QCD NN 3N 4N AV18 N 3 LO universal low-momentum interactions Bogner, Kuo, Schwenk, Furnstahl, (2003- ) need smaller basis advance EFT/RG for 3N forces first evolution of 3N forces E. Jurgenson et al., in prep March 13 ACOT Meeting 6

7 The structure of neutron-rich nuclei evolution to the neutron drip-line: limits of existence and shell structure The oxygen-fluorine anomaly? Why no Borromean oxygen nuclei? Nature (2007) O F theory without 3N interactions first results with 3N interactions 3N fits to E( 3 H), 4 He radius J. Holt (RA) Otsuka, Suzuki, Holt, Schwenk, Akaishi, in prep March 13 ACOT Meeting 7

8 Advancing theory for nuclear masses start from chiral EFT and RG evolution Bogner, Schwenk, Furnstahl, Nogga (2005) and improvements in prep. nuclear matter converged at 2nd order, 3N drives saturation, weak cutoff dependence, improved by 3N fits to 4 He radius exciting: empirical saturation within theoretical uncertainties low-momentum interactions key to develop a universal density functional from fundamental interactions (unedf.org) empirical 2009 March 13 ACOT Meeting 8

9 Advancing theory for nuclear masses impact of 3N interactions on neutron matter, K. Hebeler (RA) symmetry energy, density dependences developed density-dependent NN interactions to include 3N effects in mass calculations 3N Hebeler, Schwenk, in prep. empirical 2009 March 13 ACOT Meeting 9

10 Nuclear theory for fundamental symmetries EFT/RG: more accurate with higher orders and cutoff variation estimates theoretical uncertainties from Nogga 6 Li goal: apply to pivotal matrix elements needed to constrain beyond Standard Model physics +3N isospin-symmetry breaking corrections for superallowed beta decay initial steps: Miller, Schwenk (2008) Towner-Hardy formalism violates isospin commutation relations cannot separate ISB corrections into radial wf + SM space parts TRIUMF workshop on ISB, fall 2009 G. Grinyer (NSCL) and A.S. from Grinyer new 2008 Towner-Hardy calculation of ISB corrections (~enlarged model space) 3.1σ shift in the world-average Ft, 1.5σ in V ud largest changes in 20 years 2009 March 13 ACOT Meeting 10

11 Neutrino rates for supernovae neutrinos play crucial role for physics of stellar collapse, supernova explosions, neutron stars, first chiral EFT results for neutrino rates involving two nucleons S. Bacca and K. Hally e.g. key for muon and tau neutrino production and their spectra unified framework, determined by spin relax rate ~C σ Lykasov, Pethick, Schwenk (2008) spin relaxation rate to N 3 LO Bacca, Hally, Pethick, Schwenk (2008) leading order = one-pion exchange (standard used in SN simulations) two-pion exchange contributions and shorter-range noncentral forces reduce neutrino rates significantly more to come! Crab pulsar 2009 March 13 ACOT Meeting 11 SN1987a

12 Fermi systems with population imbalance MIT-Rice discrepancies in phase structure and critical polarization Zwierlein et al., Shin et al. (MIT, 2006), Partridge et al. (Rice, 2006) MIT Rice partial solution: finite particle number and trap-geometry effects M. Ku, J. Braun lower particle numbers, more elongated traps: energy of normal state increases superfluid extends to larger population imbalances, P c Are spin skins similar to neutron skins? Ku, Braun, Schwenk (2008) 2009 March 13 ACOT Meeting 12

13 Summary advances on many fronts nuclear forces, structure, fund symmetries, neutrino rates for astro, universal nuclear/cold atom physics low-momentum interactions enable a unified description from light to heavy nuclei and matter in astrophysics towards a predictive theory with theoretical uncertainties three-nucleon forces: a frontier for neutron-rich nuclei halo nuclei, spin-orbit effects, location of the drip line, evolution of shell structure, symmetry energy, density dependences universal many-body techniques (CC, DFT, RG, ) for nuclear, atomic, chemical systems, new materials, 2009 March 13 ACOT Meeting 13

14 Advancing theory for nuclear masses first DFT results with microscopic pairing functional from V low k + Coulomb interaction Lesinski, Duguet, Bennaceur, Meyer (2008) improvements to include induced interactions, 3N forces: S. Baroni (RA) 2009 March 13 ACOT Meeting 14