13 research outputs found
Exploring the Nucleon Structure from First Principles of QCD
Quantum Chromodynamics (QCD) is generally assumed to be the fundamental
theory underlying nuclear physics. In recent years there is progress towards investigating the
nucleon structure from first principles of QCD. Although this structure is best revealed in Deep
Inelastic Scattering, a consistent analysis has to be performed in a fully non-perturbative scheme.
The only known method for this purpose are lattice simulations. We first sketch the ideas of
Monte Carlo simulations in lattice gauge theory. Then we comment in particular on the issues
of chiral symmetry and operator mixing. Finally we present our results for the Bjorken variable
of a single quark, and for the second Nachtmann moment of the nucleon structure functions
Non-perturbative renormalization of three-quark operators
High luminosity accelerators have greatly increased the interest in
semi-exclusive and exclusive reactions involving nucleons. The relevant
theoretical information is contained in the nucleon wavefunction and can be
parametrized by moments of the nucleon distribution amplitudes, which in turn
are linked to matrix elements of local three-quark operators. These can be
calculated from first principles in lattice QCD. Defining an RI-MOM
renormalization scheme, we renormalize three-quark operators corresponding to
low moments non-perturbatively and take special care of the operator mixing.
After performing a scheme matching and a conversion of the renormalization
scale we quote our final results in the MSbar scheme at mu=2 GeV.Comment: 49 pages, 3 figure
Measuring the renormalized charge in QED
Horsley R, Gockeler M, Laermann E, Rakow PEL, Schierholz G. Measuring the renormalized charge in QED. 1990
Exploring the Nucleon Structure from First Principles of QCD
Quantum Chromodynamics (QCD) is generally assumed to be the fundamental
theory underlying nuclear physics. In recent years there is progress towards investigating the
nucleon structure from first principles of QCD. Although this structure is best revealed in Deep
Inelastic Scattering, a consistent analysis has to be performed in a fully non-perturbative scheme.
The only known method for this purpose are lattice simulations. We first sketch the ideas of
Monte Carlo simulations in lattice gauge theory. Then we comment in particular on the issues
of chiral symmetry and operator mixing. Finally we present our results for the Bjorken variable
of a single quark, and for the second Nachtmann moment of the nucleon structure functions