The Vacuum Polarization: Power Corrections beyond OPE ?
We compute the vacuum polarization on the lattice using non-perturbatively O(a) improved Wilson fermions. The result is compared with the operator product expansion (OPE).
hep-lat↗
arXiv subjects
W. Kurzinger
Publications and source records attributed to W. Kurzinger.
A lattice calculation of the nucleon's spin-dependent structure function g_2 revisited
Our previous calculation of the spin-dependent structure function g_2 is revisited. The interest in this structure function is to a great extent motivated by the fact that it receives contributions from twist-two as well as from twist-three operators already in leading order of 1/Q^2 thus offering the unique possibility of directly assessing higher-twist effects. In our former calculation the lattice operators were renormalized perturbatively and mixing with lower-dimensional operators was ignored. However, the twist-three operator which gives rise to the matrix element d_2 mixes non-perturbatively with an operator of lower dimension. Taking this effect into account leads to a considerably smaller value of d_2, which is consistent with the experimental data.
hep-lat↗
Four-quark operators in hadrons
We present calculations of matrix elements of 4-quark operators in the pion and in the nucleon extracted from quenched Monte Carlo simulations at beta = 6.0 using Wilson fermions. These operators are relevant for higher-twist effects. We are particularly careful to avoid mixing with lower-dimensional operators by choosing appropriate flavour structures.
hep-lat↗
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}^MSbar(μ=2 GeV) = 4.4(2) MeV, m_s^MSbar(μ=2 GeV) = 105(4) MeV when using r_0 to set the physical scale.
hep-lat↗