Hadron masses and decay constants in quenched QCD

We present results for the mass spectrum and decay constants using non-perturbatively O(a) improved Wilson fermions. Three values of #beta# and 30 different quark masses are used to obtain the chiral and continuum limits. Special emphasis will be given to the question of taking the chiral limit and the existence of non-analytic behavior predicted by quenched chiral perturbation theory (q#chi#PT). (orig.)Available from TIB Hannover: RA 2999(99-131) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

A lattice determination of light quark masses

A fully non-perturbative lattice determination of the up/down and strange quark masses is given for quenched QCD using both, O(a) improved Wilson fermions and ordinary Wilson fermions. For the strange quark mass with O(a) improved fermions we obtain m_s"M"S (#mu# = 2 GeV) = 105(4) MeV, using the interquark force scale r_0. Due to quenching problems fits are only possible for quark masses larger than the strange quark mass. If we extrapolate our fits to the up/down quark mass we find for the average mass m_l"M"S (#mu# = 2 GeV) = 4.4(2) MeV. (orig.)23 refs.Available from TIB Hannover: RA 2999(99-097) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Towards a lattice calculation of #DELTA#q and #delta#q

Within the framework of lattice QCD a high statistics computation of the nucleon axial and tensor charges is given. Particular attention is paid to the chiral and continuum extrapolations. (orig.)9 refs.SIGLEAvailable from TIB Hannover: RA 2999(99-064) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Light quark masses from the lattice

A completely non-perturbative estimate is given for the u/d and strange quark masses in quenched QCD using O(a) improved fermions and, for comparison, Wilson fermions. For improved fermions we find m_u_/_d"M"S(#mu#=2 GeV)=4.4(2) MeV, m_s"M"S(#mu#=2 GeV)=105(4) MeV when using r_0 to set the physical scale. (orig.)Available from TIB Hannover: RA 2999(99-114) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Nucleon form factors and O(a) improvement

Nucleon form factors have been extensively studied both experimentally and theoretically for many years. We report here on new results of a high statistics quenched lattice QCD calculation of vector and axial-vector nucleon form factors at low momentum transfer within the Symanzik improvement programme. The simulations are performed at three #kappa# and three #beta# values allowing first an extrapolation to the chiral limit and then an extrapolation in the lattice spacing to the continuum limit. The computations are all fully non-perturbative. A comparison with experimental results is made. (orig.)6 refs.SIGLEAvailable from TIB Hannover: RA 2999(98-124) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Resolving exceptional configurations in quenched lattice QCD

Quenched lattice QCD calculations with Wilson-type fermions at small quark masses are impeded by exceptional configurations. We show how this problem can be resolved in a practicable way without changing the physics in the chiral limit. (orig.)Available from TIB Hannover: RA 2999(98-146) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Mass spectrum and decay constants in the continuum limit

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#. (orig.)Available from TIB Hannover: RA 2999(98-153) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman