1. Dynamical Anisotropic-Clover Lattice Production for Hadronic Physics C. Morningstar, CMU K. Orginos, College W&M J. Dudek, R. Edwards, B. Joo, D. Richards, C. Thomas, JLab S. Wallace, U. of Maryland N. Mathur, Tata Institute M. Peardon, S. Ryan, Trinity College AHM 2011

2. Anisotropic Lattices for Nuclear Physics Hadronic spectroscopy –Hadron resonance determinations –Exotic meson spectrum and transition form-factors –HadSpec (Richards) Hadronic structure –3-D picture of hadrons from gluon & quark spin+flavor dist. –Ground & excited E&M transition FF-s –E&M polarizabilities of hadrons –HadSpec (Richards), EMC (Walker-Loud) Nuclear interactions –Nuclear processes relevant for stellar evolution –Hyperon-hyperon scattering –3 & 4 nucleon interaction properties –NPLQCD (Savage)

3. N f =2+1 Anisotropic Clover: dynamical generation Current proposal: 40 3 x256 at m ¼ ~ 230 MeV, a s =0.1227fm, a t =0.035fm –Currently running on INCITE@ORNL Extend@ANL: 32 3 £ 256 at m ¼ ~ 230 & 383 MeV Future INCITE+ESP: 48 3 x384 at m ¼ ~ 140 MeV

4. Priorities Current calculations at m ¼ ~ 230 MeV Finite volume effects: –Crucial for resonance/scattering extraction Chiral effects (large pion mass) appear large –Excited resonance: chiral extrap. problematic High statistics important (~10k traj. -> 1000 cfgs) Discretization effects appear small/negligible –Evidence via spectra of Subduced operators Priorities: 1.Physical limit @ 6fm box -> 48 3 x384 2.Second lattice spacing @ ~500MeV pion mass

5. Claim: discretization effects small/negligible Anisotropic gauge (Symanzik) action & fermion (Clover) action: –Fixed Clover coefficients c t and c s (Chen): –Bare gauge ° g fermion ° f anisotropy & bare quark mass m 0 Impose PCAC & rotational symmetry via SF techniques (m q = 0) O(a) effects in spectrum eliminated via on-shell improvement Discretization effects gggg 175 MeV 0 MeV ffff 175 MeV 0 MeV Anisotropies

6. Claim: discretization effects small/negligible No dimension 5 rotation breaking terms –Also true for anisotropic actions Rotation breaking pushed to O(a 2 ) –True for both spectrum and wave-function (operator) overlaps Discretization effects

7. Claim: discretization effects small/negligible In fact, rotation breaking negligible: Discretization effects arXiv:1104.5152 Basis of 3-quark ops with continuum J P Mix in lattice irreps Tiny off-diagonal mixing

8. Claim: discretization effects small/negligible No discernible rotation breaking Discretization effects arXiv:1104.5152 Basis test: restrict operators Remarkable realization of rotational symmetry Determine J=7/2 for first time

9. Scattering processes: range of interaction Volume effects: two varieties: exp(-m ¼ *L) effects [NPLQCD: 1104.5152] Accessible momentum effects: –Determine partial-wave phase shifts ± L (E) vs. E(k 2 ) –Critical component in resonance determinations Volume effects 1011.6352 I=2 ¼¼ L=0 & 2 scattering phase shift ± 0 (E) & ± 2 (E) First ever L=2 phase shift 24 3 20 3 16 3

10. Extract resonance mass Can then chiral extrapolate Obviously want light pion masses Perilous waters: the excited J P = ½ + “Roper” Resonance mass and chiral extrapolations 1104.5152 Four-fold degeneracy Big discrepancy: operator basis! Need ops featuring orbital structure & multi-particle ops

11. Spin identified Nucleon & Delta spectrum 11 arXiv:1104.5152 m ¼ ~ 520MeV

12. Spin identified Nucleon & Delta spectrum 12 Mass and overlaps: assign into multiplets arXiv:1104.5152 453123 2 1 221 1 1 SU(6)xO(3) counting No parity doubling m ¼ ~ 520MeV

13. Current plans Gauge production: –Emphasis on hadronic and nuclear physics –ORNL: INCITE time for 40 3 £ 256, m ¼ ~230MeV –ANL: extend 32 3 £ 256 ensembles Distillation(+variants) + subduction –Flexible: framework useful for 2-pt and 3-pt –In-place: multi-particle ops & annihilation diagrams Role expanding for GPU-s –Powerful resource for inversions –ECC+double precision -> handle contractions –Major software focus

14. Backup

15. Spectroscopy: exotic mesons