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

Light quark masses for dynamical, non-perturbatively O(a) improved Wilson fermions

We present results for the light quark masses in lattice QCD with two degenerate flavours of dynamical fermions. We used configurations generated by the UKQCD and QCDSF collaborations at six different combinations of #beta# and #kappa#"s"e"a. (orig.)Available from TIB Hannover: RA 2999(00-152) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Improved quenched QCD on large lattices - first results

Continuing our investigations of quenched QCD with improved fermions we have started simulations for lattice size 32"3 x 64 at #beta# = 6.2. We present first results for light hadron masses at #kappa# = 0.13520, 0.13540, and 0.13555. Moreover we compare our initial experiences on the T3E with those for APE/Quadrics systems. (orig.)Available from FIZ Karlsruhe / 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

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

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

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

O(a) improvement of nucleon matrix elements

We report on preliminary results of a high statistics quenched lattice QCD calculation of nucleon matrix elements within the Symanzik improvement programme. Using the recently determined renormalisation constants from the alpha collaboration we present a fully non-pertubative calculation of the forward nucleon axial matrix element with O(a) lattice artifacts completely removed. Runs are made at #beta# = 6.0 and #beta# = 6.2, in an attempt to check scaling and O(a"2) effects. We shall also briefly describe results for left angle x right angle, the matrix element of a higher derivative operator. (orig.)SIGLEAvailable from FIZ Karlsruhe / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Higher-twist corrections to nucleon structure functions from lattice QCD

A genuinely non-perturbative evaluation of higher-twist contributions to the structure functions of the nucleon, with all mixing effects and renormalon ambiguities taken care of, is presented. Higher-twist corrections turn out to be significant at moderate values of q"2. (orig.)6 refs.Available from TIB Hannover: RA 2999(99-069) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman