PartialWave Analysis of SinglePion Production Reactions.pdfVIP

Partial-Wave Analysis of Single-Pion Production Reactions ∗ ∗ ∗ ∗ R.A. Arndt , W.J. Briscoe , I.I. Strakovsky and R.L. Workman ∗ Center for Nuclear Studies, Department of Physics, The George Washington University, Washington, D.C. 20052, USA 6 0 0 Abstract. We present an overview of our efforts to analyze pion-nucleon elastic scattering 2 data, along with data from related photo- and electroproduction reactions, in order to study l the baryon spectrum. We then focus on the ∆(1232) resonance. Fits to pion photo- and u electroproduction data have been used to extract values for the REM = E2/M1 and RSM = J 2 S2/M1 ratios as functions of Q . These results are compared to other recent determinations. 0 1 Keywords: Partial-Wave Analysis PACS: 14.20.Gk, 11.80.Et, 13.30.Eg 1 v 7 Many of our fits to scattering data have been motivated by ongoing studies 1 of the N ∗ properties [1]. Most of these require, as input, amplitudes extracted 0 7 from elastic pion-nucleon scattering data [2]. Our pion photoproduction multipoles 0 6 0 / h t - l c u n : v i X r FIGURE 1. ∆ multipoles from analysis of scattering data − a Road Map. a are determined using a K-matrix formalism, based upon pion-nucleon partial-wave amplitudes [3]. The electroproduction analysis is similarly anchored to our Q2 = 0 photoproduction results, with additional factors intended to account for the Q2