Terrence Draper

Glueball spectrum and matrix elements on anisotropic lattices

The glueball-to-vacuum matrix elements of local gluonic operators in scalar, tensor, and pseudoscalar channels are investigated numerically on several anisotropic lattices with the spatial lattice spacing ranging from 0.1-0.2 fm. These matrix elements are needed to predict the glueball branching ratios in J/{psi} radiative decays which will help identify the glueball states in experiments. Two types of improved local gluonic operators are constructed for a self-consistent check and the finite-volume effects are studied. We find that lattice spacing dependence of our results is very weak and the continuum limits are reliably extrapolated, as a result of improvement of the lattice gauge action and local operators. We also give updated glueball masses with various quantum numbers.

Decuplet baryon structure from lattice QCD

The electromagnetic properties of the SU(3)-flavor baryon decuplet are examined within a lattice simulation of quenched QCD. Electric charge radii, magnetic moments, and magnetic radii are extracted from the {ital E}0 and {ital M}1 form factors. Preliminary results for the {ital E}2 and {ital M}3 moments are presented, giving the first model-independent insight to the shape of the quark distribution in the baryon ground state. As in our octet-baryon analysis, the lattice results give evidence of spin-dependent forces and mass effects in the electromagnetic properties. The quark charge distribution radii indicate these effects act in opposing directions. Some baryon dependence of the effective quark magnetic moments is seen. However, this dependence in decuplet baryons is more subtle than that for octet baryons. Of particular interest are the lattice predictions for the magnetic moments of {Omega}{sup {minus}} and {Delta}{sup ++} for which new recent experimental measurements are available. The lattice prediction of the {Delta}{sup ++}/{ital p} ratio appears larger than the experimental ratio, while the lattice prediction for the {Omega}{sup {minus}}/{ital p} magnetic moment ratio is in good agreement with the experimental ratio.

Study of pentaquarks on the lattice with overlap fermions

We present a quenched lattice QCD calculation of spin-

Baryon octet to decuplet electromagnetic transitions.

1/2

Strangeness and charmness content of the nucleon from overlap fermions on 2+1-flavor domain-wall fermion configurations

five-quark states with

Lattice study of light scalar tetraquarks with I=0,2,1/2,3/2: Are \sigma and \kappa tetraquarks?

uudd\overline{s}

Low-dimensional long-range topological structure in the QCD vacuum☆

quark content for both positive and negative parities. We do not observe any bound pentaquark state in these channels for either

Recent developments in weak matrix element calculations

I=0

π N and Strangeness Sigma Terms at the Physical Point with Chiral Fermions

or

The pion form factor in lattice QCD

I=1