Non-perturbative renormalisation and improvement of the local vector current for quenched and unquenched Wilson fermions

Abstract

By considering the local vector current between nucleon states and imposing charge conservation, we determine its renormalisation constant and quark mass improvement coefficient for Symanzik $O(a)$ improved Wilson fermions. The computation is first performed for quenched fermions (and for completeness also with unimproved fermions) and compared against known results. The two-flavour unquenched case is then considered.

Comments: 15 pages, 5 figures, Latex, Final version