Comment on "Nucleon form factors and a nonpointlike diquark"

Authors of Phys. Rev. C 60, 062201 (1999) presented a calculation of the electromagnetic form factors of the nucleon using a diquark ansatz in the relativistic three-quark Faddeev equations. In this Comment it is pointed out that the calculations of these form factors stem from a three-quark bound state current that contains overcounted contributions. The corrected expression for the three-quark bound state current is derived.Comment: 6 pages, 1 figure, revtex, eps

In-matter three-body problem

We formulate three-dimensional equations for the finite temperature in-matter three-body problem. Our approach takes into account the full infinite series for the effective pair-interaction kernel, so that all possible two-body sub-processes allowed by the underlying Hamiltonian are retained.Comment: 5 pages, contribution to The 16th National Congress 2005 - Australian Institute of Physic

Few-Body Descriptions of the piNN System in Three and Four Dimensions

We summarise the recent theoretical progress in few-body descriptions of the piNN system. Previous descriptions, both three- and four-dimensional, are shown to possess serious theoretical inconsistencies. We illustrate how three-dimensional approaches suffer from renormalisation problems, and how four-dimensional descriptions contain both overcounting and undercounting of diagrams. We then show how such theoretical problems have been recently overcome, leading to new practical few-body equations for the piNN system.Comment: LaTeX, epsf, 8 pages + 6 figures (appended as uuencoded PS-files), invited talk at Symposium on Meson-Nucleon Physics..., Blaubeuren, Germany, July, '95. Shortened version with minor correction

On the Wilsonian renormalization group equation for nuclear current operators

We present the solution to the recently derived Wilsonian renormalization group (RG) equation for nuclear current operators. In order to eliminate the present ambiguity in the RG equation itself, we introduce a new condition specifying the cutoff independence of the five point Green function corresponding to the two-body propagator with current operator insertion. The resulting effective current operator is then shown to obey a modified Ward-Takahashi identity which differs from the usual one, but that nevertheless leads to current conservation.Comment: 12 page