Electromagnetic form factors with FLIC fermions

The fat-link irrelevant clover (FLIC) fermion action provides a new form of nonperturbative O(a) improvement and allows efficient access to the light quark-mass regime. FLIC fermions enable the construction of the nonperturbatively O(a)-improved conserved vector current without the difficulties associated with the fine tuning of the improvement coefficients. The simulations are performed with an O(a"2) mean-field improved plaquette-plus-rectangle gluon action on a 20"3 x 40 lattice with a lattice spacing of 0.128 fm, enabling the first simulation of baryon form factors at light quark masses on a large volume lattice. Magnetic moments, electric charge radii and magnetic radii are extracted from these form factors, and show interesting chiral nonanalytic behavior in the light quark mass regime. (orig.)SIGLEAvailable from TIB Hannover: RA 2999(03-157) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Electromagnetic form factors wih FLIC fermions

The Fat-Link Irrelevant Clover (FLIC) fermion action provides a new form of nonperturbative #sigma#(a) improvement and allows efficient access to the light quark-mass regime. FLIC fermions enable the construction of the nonperturbatively #sigma#(a)-improved conserved vector current without the difficulties associated with the fine tuning of the improvement coefficients. The simulations are performed with an #sigma#(a"2) mean-field improved plaquette-plus-rectangle gluon action on a 20"3 x 40 lattice with a lattice spacing of 0.128 fm, enabling the first simulation of baryon form factors at light quark masses on a large volume lattice. Magnetic moments, electric charge radii and magnetic radii are extracted from these form factors, and show interesting chiral nonanalytic behavior in the light quark mass regime. (orig.)Available from TIB Hannover: RA 2999(03-210) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Precise determination of the strangeness magnetic moment of the nucleon

By combining the constraints of charge symmetry with new chiral extrapolation techniques and recent low mass lattice QCD simulations of the individual quark contributions to the magnetic moments of the nucleon octet, we obtain a precise determination of the strange magnetic moment of the proton. The result, namely G"s_M = -0.051 #+-# 0.021 #mu#_N, is consistent with the latest experimental measurements but an order of magnitude more precise. This poses a tremendous challenge for future experiments. (orig.)Available from TIB Hannover: RA 8919(04-075) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Systematic uncertainties in the precise determination of the strangeness magnetic moment of the nucleon

Systematic uncertainties in the recent precise determination of the strangeness magnetic moment of the nucleon are identified and quantified. In summary, G_M"s=-0.046 #+-# 0.019 #mu#_N. (orig.)SIGLEAvailable from TIB Hannover: RA 2999(05-014) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman