We perform a high-statistics precision calculation of nucleon matrix elements using an open sink method allowing us to explore a wide range of sink-source time separations. In this way the influence of excited states of nucleon matrix elements can be studied. As particular examples we present results for the nucleon axial charge gA and for the first moment of the isovector unpolarized parton distribution <x>u−d. In addition, we report on preliminary results using the generalized eigenvalue method for nucleon matrix elements. All calculations are performed using Nf=2+1+1 maximally twisted mass Wilson fermions.
Cite
@article{arxiv.1112.2931,
title = {Excited State Effects in Nucleon Matrix Element Calculations},
author = {Constantia Alexandrou and Martha Constantinou and Simon Dinter and Vincent Drach and Karl Jansen and Theodoros Leontiou and Dru B. Renner},
journal= {arXiv preprint arXiv:1112.2931},
year = {2011}
}
Comments
7 pages, 4 figures. Talk given at the XXIX International Symposium on Lattice Field Theory - Lattice 2011, Lake Tahoe, California, USA