Truncated partial-wave analysis in pion-electroproduction

Abstract

Numerical and pseudo data for pion electroproduction from four reaction channels, p(γ*, π 0)p, p(γ*, π +)n, n(γ*, π− )p, and n(γ*, π 0)n, from threshold up to W = 1.575 GeV are used to perform a single energy partial wave analysis. As a constraint, higher partial waves are taken from the MAID07 model and lower partial waves are fitted. It is demonstrated that truncated partial wave analysis in a full isospin can be obtained with this procedure. The results for photon virtuality Q 2 = 0.5 GeV2 are presented. Electromagnetic Eℓ± , Mℓ± , and longitudinal Lℓ± multipoles are presented and discussed. In the first step, numerical data are generated, and the optimal number of lower partial waves required for a good data fit is determined. In the second step, the same procedure is applied using generated pseudo data.