CANADA’S NATIONAL LABORATORY FOR PARTICLE AND NUCLEAR PHYSICSOwned and operated as a joint venture by a consortium of Canadian universities via acontribution through the National Research Council Canada

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’unecontribution administrée par le Conseil national de recherches Canada

Theory Group Plans and Highlights

Achim Schwenk

Theory Group Leader, TRIUMF

Affiliate Prof. University of Washington, Joint Institute for Nuclear Astrophysics (JINA)

2009 March 13 ACOT Meeting 2

Group overviewpresently 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 2010-2015 in nuclear theory (astro/symmetries)→ research in nuclear (4) and particle (3) theory

successful RAsJ. Braun → 6-year position at U of Jena; S. Baroni → joint INT, now Seattle4 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 3

Recent successesorganization of workshops in 2008TeV-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 nucleiTRIUMF-GSI/FAIR workshop on future collaborations (J. Dilling and A.S.)

unique training/research experience for students in Canadaco-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/workshopsincludes plenary talks at ENAM08 and PANIC08

part of major international initiatives: JINA, UNEDF

2009 March 13 ACOT Meeting 4

Plansnext exciting era with D. Morrissey and new hireensure 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 theoryincrease number of students to 1-2 per scientist

exploit more synergies with experimental program

establish Theory Group as center of activity for the broaderCanadian subatomic theory communityplenary 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 5

Recent highlightsnuclear forces and the renormalization group:universal low-momentum interactions, among top 5 cited papers in nuclearstructure/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 projectto 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 6

The nuclear forces frontierdevelopment of systematic effective field theory for nuclear forcesand renormalization group evolution to apply to all nucleiEFT/RG interactions: top workhorses in nuclear theory, connected to QCD

advance EFT/RG for 3N forcesfirst evolution of 3N forces E. Jurgenson et al., in prep.

NN 3N 4NAV18

N3LO

universallow-momentuminteractionsBogner, Kuo, Schwenk,Furnstahl,… (2003-…)need smaller basis

2009 March 13 ACOT Meeting 7

The structure of neutron-rich nucleievolution to the neutron drip-line: limits of existence and shell structureThe oxygen-fluorine anomaly? Why no Borromean oxygen nuclei?

first results with 3N interactions3N fits to E(3H), 4He radius

J. Holt (RA)Otsuka, Suzuki, Holt, Schwenk, Akaishi, in prep.

OF

Nature (2007)

theory without 3N interactions

2009 March 13 ACOT Meeting 8

Advancing theory for nuclear massesstart from chiral EFT and RG evolutionnuclear matter converged at ≈ 2nd order, 3N drives saturation,weak cutoff dependence, improved by 3N fits to 4He radius

exciting: empirical saturation within theoretical uncertaintieslow-momentum interactions key to develop a universal density functionalfrom fundamental interactions (unedf.org)

empirical

Bogner, Schwenk, Furnstahl, Nogga (2005)and improvements in prep.

2009 March 13 ACOT Meeting 9

Advancing theory for nuclear massesimpact of 3N interactions on neutron matter, K. Hebeler (RA)symmetry energy, density dependences

developed density-dependent NN interactionsto include 3N effects in mass calculations

empirical

Hebeler, Schwenk, in prep.

3N

2009 March 13 ACOT Meeting 10

Nuclear theory for fundamental symmetriesEFT/RG: more accurate with higher orders andcutoff variation estimates theoretical uncertaintiesgoal: apply to pivotal matrix elements needed to constrainbeyond Standard Model physics

isospin-symmetry breaking correctionsfor superallowed beta decayinitial steps: Miller, Schwenk (2008)

Towner-Hardy formalism violatesisospin commutation relationscannot separate ISB corrections intoradial wf + SM space parts

TRIUMF workshop on ISB, fall 2009G. Grinyer (NSCL) and A.S.

+3N

6Lifrom Nogga

from Grinyer

new 2008 Towner-Hardy calculationof ISB corrections (~enlarged model space)3.1σ shift in the world-average Ft, 1.5σ in Vudlargest changes in 20 years

2009 March 13 ACOT Meeting 11

Neutrino rates for supernovaeneutrinos play crucial role for physics of stellarcollapse, supernova explosions, neutron stars,…

first chiral EFT results for neutrino ratesinvolving two nucleons S. Bacca and K. Hallye.g. key for muon and tau neutrino production and their spectra

unified framework, determined by spin relax rate ~Cσ Lykasov, Pethick, Schwenk (2008)

spin relaxation rate to N3LOBacca, Hally, Pethick, Schwenk (2008)

leading order = one-pion exchange(standard used in SN simulations)

two-pion exchange contributionsand shorter-range noncentral forcesreduce neutrino rates significantly

more to come!

Crab pulsar SN1987a

2009 March 13 ACOT Meeting 12

Fermi systems with population imbalanceMIT-Rice discrepancies in phase structure and critical polarizationZwierlein et al., Shin et al. (MIT, 2006), Partridge et al. (Rice, 2006)

MIT Rice

partial solution: finite particle number andtrap-geometry effects M. Ku, J. Braunlower particle numbers, more elongated traps:energy of normal state increases → superfluidextends to larger population imbalances, Pc

Are spin skins similar to neutron skins?

Ku, Braun, Schwenk (2008)

2009 March 13 ACOT Meeting 13

Summaryadvances on many frontsnuclear forces, structure, fund symmetries, neutrino rates for astro,universal nuclear/cold atom physics

low-momentum interactions enable a unified descriptionfrom light to heavy nuclei and matter in astrophysics

towards a predictive theory with theoretical uncertainties

three-nucleon forces: a frontier for neutron-rich nucleihalo nuclei, spin-orbit effects, location of the drip line, evolution ofshell structure, symmetry energy, density dependences

universal many-body techniques (CC, DFT, RG,…)for nuclear, atomic, chemical systems, new materials,…

2009 March 13 ACOT Meeting 14

Advancing theory for nuclear massesfirst DFT results with microscopic pairing functionalfrom Vlow k + Coulomb interaction Lesinski, Duguet, Bennaceur, Meyer (2008)

improvements to include induced interactions, 3N forces: S. Baroni (RA)