Related papers: N* Spectrum using an O(a)-Improved Fermion Action
The electromagnetic, axial and pseudoscalar nucleon to Delta form factors are calculated using dynamical domain wall fermions at a lattice spacing of a = 0.114 fm on a lattice of spatial size 2.74 fm and pion mass of 331 MeV. Pion pole…
We compute the complete O(alpha^2) QED corrections to the electron energy spectrum in unpolarized muon decay, including the full dependence on the electron mass. Our calculation reduces the theoretical uncertainty on the electron energy…
We consider, in a model-independent framework, the potential for observing dark matter in neutrino detectors through the interaction $\bar{f} p \to e^+ n$, where $f$ is a dark fermion. Operators of dimension six or less are considered, and…
The decay Delta^+ --> p gamma is studied in the 1/N_c expansion of QCD. The ratio of the helicity amplitudes is determined to be A_{3/2}/A_{1/2} = \sqrt{3} + O(1/N_c^2). Equivalently, the ratio E2/M1 of the multipole amplitudes is predicted…
We present results on the axial and the electromagnetic form factors of the nucleon, as well as, on the first moments of the nucleon generalized parton distributions using maximally twisted mass fermions. We analyze two N_f=2+1+1 ensembles…
We report our recent effort on the extraction of N*- and Delta*-resonance parameters (pole masses, coupling constants, etc.) through the comprehensive analysis of pion- and photon-induced pi N, eta N, K Lambda, and K Sigma production…
Neutrino oscillation experiments require accurate reconstructions of neutrino energies, which depend in part on a theoretical understanding of the axial $N \rightarrow \Delta$ transition form factors. Lattice QCD studies of this transition…
We present results of a high statistics study of the quenched spectrum using Wilson fermions at $\beta=6.0$ on $32^3 \times 64$ lattices. We calculate the masses of mesons and baryons composed of both degenerate and non-degenerate quarks.…
The coupled pi+N, eta+N, gamma+N systems are described by a K-matrix method. The parameters in this model are adjusted to get an optimal fit to pi+N -> pi+N, pi+N -> eta+N, gamma+N -> pi+N and gamma+N -> eta+N data in an energy range of…
We have determined the spectra of neutrons and protons following the decay of $\Lambda$ hypernuclei through the one- and two-nucleon induced mechanisms. The momentum distributions of the primary nucleons are calculated and a Monte Carlo…
We calculate the low-lying spectra for the positive-parity $\Delta$ and $N$ at two pion masses of 358 and 278 MeV using an isotropic clover action with two degenerate light-quaark and one strange-quark flavors through the application of the…
We calculate the light `glueball' mass spectrum in N_f=2 lattice QCD using a fermion action that is non-perturbatively O(a) improved. We work at lattice spacings a ~0.1 fm and with quark masses that range down to about half the strange…
A lot of progress has been made in the direct determination of nucleon sigma terms. Using similar methods, we consider the sigma terms of the other octet baryons as well. These are determined on CLS gauge field ensembles employing the…
A global study of the negative parity non-strange baryon observables is performed in the frame- work of the 1/Nc expansion. Masses, partial decay widths and photo-couplings are simultaneously analyzed. A main objective is to determine the…
We compute the light hadron mass spectrum in quenched lattice QCD at $\beta = 6.0$ using the Sheikholeslami-Wohlert fermionic action. The calculation is done for several choices of the coefficient $c_{SW}$, including $c_{SW} = 0$ and the…
We extend our calculations with the second-order tree-level and tadpole improved next-nearest-neighbor action to meson-meson systems. Correlation matrices built from interpolating fields representing two pseudoscalar mesons (pion-pion) with…
We present first results for light hadron masses, quark masses and decay constants in the continuum limit using O(a) improved fermions at three different values of the gauge coupling \beta.
The 1/N expansion of QCD can be used to calculate properties of nucleons and Delta baryons, such as masses, magnetic moments, and pion couplings. The predictions of the 1/N expansion are in excellent agreement with the experimental data.…
A covariant spectator quark model is applied to study the gamma N -> N*(1535) reaction in the large Q2 region. Starting from the relation between the nucleon and N*(1535) systems, the N*(1535) valence quark wave function is determined…
We investigate Theta^+ production via photon and nucleon induced reactions. We observe that the positive parity Theta^+ production provides about ten times larger total cross sections than those of the negative parity one in both photon and…