Progress in resolving charge symmetry violation in nucleon structure

Recent work unambiguously resolves the level of charge symmetry violation in moments of parton distributions using 2+1-flavor lattice QCD. We introduce the methods used for that analysis by applying them to determine the strong contribution to the proton-neutron mass difference. We also summarize related work which reveals that the fraction of baryon spin which is carried by the quarks is in fact structure-dependent rather than universal across the baryon octet.Comment: 8 pages, 4 figures; presented at "The Seventh International Symposium on Chiral Symmetry in Hadrons and Nuclei", BeiHang Univ. Beijing, Chin

Updated Analysis of the Mass of the H Dibaryon from Lattice QCD

Recent lattice QCD calculations from the HAL and NPLQCD Collaborations have reported evidence for the existence of a bound state with strangeness -2 and baryon number 2 at quark masses somewhat higher than the physical values. A controlled chiral extrapolation of these lattice results to the physical point suggested that the state, identified with the famed H dibaryon, is most likely slightly unbound (by 13 $\pm$ 14 MeV) with respect to the $\Lambda--\Lambda$ threshold. We report the results of an updated analysis which finds the H unbound by 26 $\pm$ 11 MeV. Apart from the insight it would give us into how QCD is realized in Nature, the H is of great interest because of its potential implications for the equation of state of dense matter and studies of neutron stars. It may also explain the enhancement above the $\Lambda--\Lambda$ threshold already reported experimentally. It is clearly of great importance that the latter be pursued in experiments at the new J-PARC facility.Comment: Invited presentation at APPC12 (12th Asia Pacific Physics Conference), July 14-19, 2013, Chiba, Japa

Sigma terms from an SU(3) chiral extrapolation

We report a new analysis of lattice simulation results for octet baryon masses in 2+1-flavor QCD, with an emphasis on a precise determination of the strangeness nucleon sigma term. A controlled chiral extrapolation of a recent PACS-CS Collaboration data set yields baryon masses which exhibit remarkable agreement both with experimental values at the physical point and with the results of independent lattice QCD simulations at unphysical meson masses. Using the Feynman-Hellmann relation, we evaluate sigma commutators for all octet baryons. The small statistical uncertainty, and considerably smaller model-dependence, allows a signifcantly more precise determination of the pion-nucleon sigma commutator and the strangeness sigma term than hitherto possible, namely {\sigma}{\pi}N=45 \pm 6 MeV and {\sigma}s = 21 \pm 6 MeV at the physical point.Comment: 4 pages, 4 figure

Large-scale Monte Carlo simulations of the isotropic three-dimensional Heisenberg spin glass

We study the Heisenberg spin glass by large-scale Monte Carlo simulations for sizes up to 32^3, down to temperatures below the transition temperature claimed in earlier work. The data for the larger sizes show more marginal behavior than that for the smaller sizes, indicating the lower critical dimension is close to, and possibly equal to three. We find that the spins and chiralities behave in a quite similar manner.Comment: 8 pages, 8 figures. Replaced with published versio

Single spin- and chiral-glass transition in vector spin glasses in three-dimensions

Results of Monte Carlo simulations of XY and Heisenberg spin glass models in three dimensions are presented. A finite size scaling analysis of the correlation length of the spins and chiralities of both models shows that there is a single, finite-temperature transition at which both spins and chiralities order.Comment: 5 pages, 5 figures. Replaced by published versio

LIVE HOG AND PORK IMPORTS: PAST AND PROJECTED CONSEQUENCES FOR THE U.S. PORK SECTOR

The U.S. pork sector is modeled to simulate the effects of alternative import levels on prices, production, consumption, farm receipts, and consumer expenditures. Over the 1983-1985 period, producers annually received $600 million less due to increasing imports than if imports had remained at the 1979-1982 average. Farm prices and slaughter were lower by$2.21 per hundredweight and .1 million head annually, respectively. Four simulations reflecting alternative import paths over the period 1986-1992 were examined. With lower imports (relative to current levels), production and farm prices rise significantly in the long run; consumers purchase less and pay more.International Relations/Trade,